Global Warming
Difference in average global temperature surface compared to the 1961-1990 average, over the period 1880-2009. The global warming , also known as global warming or global warming is a phenomenon of increasing the temperature average of oceans and the atmosphere , around the world for several years. In its common, this term is applied to a trend of global warming observed over the last decades of the xx th century . An Intergovernmental Panel on Climate Change (IPCC) is developing a scientific consensus on this issue. His last and fourth report , which was attended by over 2500 scientists from 130 countries 1 , says that global warming since 1950 is most likely c 1 from human, that is to say human. These conclusions were endorsed by more than 40 scientific societies and academies of science, including all national academies of science of the major industrialized countries 2 . Projections of climate models presented in the latest IPCC report indicate that the surface temperature of the globe is likely to increase from 1.1 to 6.4 ° C during the additional xxi th century . The differences between the projections from the use of models with different sensitivities to the concentration of greenhouse gases and using different estimates for future emissions . Most studies focus on the period up to 2100. However, warming is expected to continue beyond that date even if emissions stop because of the large heat capacity of the oceans and the life of the carbon dioxide in the atmosphere. This implies Relevant Life Policies strong the human and environmental medium to long term. Uncertainties about the increase in temperature overall average remaining due to the precision of Wire Cart Covers the models used, and state and individual behaviors present and future. The economic, political, social, environmental, or moral, is the major, they give rise to many debates, internationally, as well as controversy .
Climatic cycles Main article: Climate Change . The global climate of the Earth is experiencing changes more or less cyclical warming alternating with chills that differ in duration (a few thousand to several million years) and their amplitude. For 60 million years the Earth experienced a general cooling, with the appearance of the Antarctic ice sheet there are 35 million years and the ice cap in the northern hemisphere there are 4 million years 3 . From 800,000 years, Earth’s climate are several cycles of glaciation and warming of about 100 000 years each. Each cycle begins with a sudden warming followed by a warm period from 10 000 to 20 000 years ago, called interglacial period . This period is followed by a gradual cooling and installation of an ice age . At the end of glaciation, an abrupt warming begins a new cycle. We are living for more than 10 000 years in an interglacial period ( see figure ), and the current climate change is placed in relation to the natural warming after the last glaciation. Through the study of ice cores and specifically the analysis of the composition isotope of oxygen trapped in the ice, the air temperatures of glacial cycles of the Quaternary period have been reconstructed 4 . The deepest ice core was drilled in the Epica project in Antarctica , more than 3500 meters deep and can be traced back the history of climate in Antarctica until 800 000 years 5 . The ice cores contain air bubbles and guidance on the gas content of the atmosphere of yesteryear. Some believe that this shows that global temperatures are related to the amount of greenhouse gas (GHG) emissions in the atmosphere but we must be careful not to confuse cause and effect. Indeed, 90% of the greenhouse effect is produced by water vapor and clouds, this does not prove that CO 2 has a significant influence on the climate. [ref. needed] . Climate variations are correlated with those of the insolation , the parameters Milankovic , the albedo , the solar cycles and concentrations in the atmosphere gas greenhouse effect as carbon dioxide and aerosols . [ref . required] Amplitudes of climatic variations
Changes in the global climate since 540 million years. During the Quaternary , the amplitude of the temperature was around 10 ° C , but with increases in temperature never exceeded by more than 4 ° C mean annual temperature of the end of the xx th century. In contrast to earlier cycles, like during the Permian , the average global temperature reached 22 ° C or 8 ° C higher compared to the average current, as shown on the graph against. During the warm periods that lasted tens of millions of years, the Earth was devoid of polar ice caps . Historical times
Detailed explanation of the graph ( in ) . The reconstructions are made from the dendrochronology , measures in the glaciers and more. Within the large terrestrial climatic fluctuations, variations are shorter and more limited in intensity. Thus, during the last millennium, has appeared in Western Europe a warm period between the x th century [ref. needed] 6 and the xiii th century century, called “ Medieval Warm Period “is the time when browsers Vikings discovered and named the Greenland (literally “Green Country”) and established colonies in the far south of the island. Similarly, the era of modern times (1550-1850) went through a cooling period that historians call the “ little ice age “characterized by very cold winters, the terrible winter of 1708 – 1709 . That year, grain failed in most of France, and only Normandy, Perche and the coasts of Britain were able to produce enough grain to ensure the seeds. In the Paris region, the 
price of bread reached in June 1709, 35 in the nine books instead of seven as usual. San Diego Homes For Rent Many trees froze to the sapwood, and the vine disappeared from many parts of France, the lowest temperatures are reached between 10 and 21 January 7 . According to reconstructions 8 temperatures produced by climate scientists, the last decade of the xx th century and beginning of the xxi th century is the warmest period of the last two millennia (see chart). Our time would be a little hotter (a few tenths of degrees) than was the Medieval Warm Period . Observations linked to global warming today
Several changes were observed in the world that led to finding a global warming. In France, a national observatory on the effects of global warming (ONERC), established in 2001, coordinates the observations. Temperature changes
Average surface temperature between 1856 and 2009. The drop-off in 1992-1993 is attributed to aerosols released during the eruption of Pinatubo in 1991. The ground temperature measurements made during the xx th century show a rise in average temperature. This warming would have two phases, the first from 1910 to 1945, the second from 1976 to today. These two phases are separated by a period of slight cooling. This global warming seems more correlated with a sharp increase in atmospheric concentrations of several greenhouse gases , including carbon dioxide , the methane and nitrous oxide 9 . The 10 warmest years between 1880 and 2010 10 Years Deviations from the average for 1961-1990 A 1998 0.52 ° C 2 2010 0.50 ° C 3 2005 0.47 ° C 4 2003 0.46 ° C 5 2002 0.46 ° C 6 2009 0.44 ° C 7 2004 0.43 ° C 8 2006 0.43 ° C 9 2007 0.40 ° C 10 2001 0.40 ° C The rise in average global temperature between 1906 and 2005 is estimated at 0.74 ° C (plus or minus 0.18 ° C near), a rise of 0.65 ° C during the period 1956-2006 only 11 , 12 . Analysis of the Goddard Institute for Space Studies (GISS) at NASA showed that the average global temperature of surface air between 1997 and 2008 was 0.44 ° C above the world average established between 1951 1980 and 13 . free ipad According to the same institute in 2010 was the warmest year 14 (tied with 2005, the free auto insurance quotes average global temperature), and marks the end of the decade and a series of 30 years most warmest recorded by the weather, despite a net cooling of certain areas of the northern hemisphere by La Niña 15 , and despite the effects of low solar activity . The global warming has continued without interruption from 1980 to 2010, over 30 years, no time generally regarded as sufficient by meteorologists as a trend in the short term 16 . Among the ten warmest years in a century, nine post-2000. The fourth report of the IPCC estimated as very probable that average temperatures in the northern hemisphere were higher during the second half of the xx th century than during any other period of fifty years during the last five centuries, and probable that they were the highest since at least 1300 years has a . Precipitation The fourth IPCC report, the distribution of rainfall has changed during the xx th century. In particular, precipitation would have increased significantly in eastern North America and South America, northern Europe and northern and central Asia, while they declined in the Sahel, Mediterranean, southern Africa and parts of South Asia has one . Other experts believe the current data, however, too few and incomplete to a tendency to increase or decrease in rainfall could be reached on areas of this magnitude 17 . There is also since 1988 a significant reduction in spring snow cover in mid-latitudes of the northern hemisphere. This decline is of concern because the snow cover contributes to soil moisture and water resources 11 . Melting of the ice
In 2005 and 2007 have been achieved the record minimum extent of sea ice Arctic. Several studies indicate that the ice floes are being reduced. The area of sea ice Storage Bins has experienced very rapid decline from 8.5 electronic cigarette million km 2 during the period 1950-1975 to 5.5 million km 2 in 2010 3 . The dedicated satellite CryoSat-2 was launched into orbit in April 2010 18 after the failure of the first satellite CryoSat in 2005. It should provide more precise information on the quantities of polar ice 19 . In Arctic Satellite observations show that the ice floes of the area lost in the Arctic Ocean 20 . In addition, thinning of the ice floes, especially around the north pole, was observed 21 . The average age of the ice over the period 1988-2005, from over six years to less than three years 22 . The reduction in the average range of Arctic sea ice since 1978 is about 2.7% per decade (plus or minus 0.6%), its extent in late summer minimum declining by 7.4% decade (plus or minus 2.4%) 11 . The warming in this region is of the order of 2.5 ° C 23 (instead of 0.7 ° C on average over the planet), and the average thickness of ice has lost 40% of its value between periods 1958-1976 and 1993-1997 24 . 2007 marks a minimum of sea ice in summer 25 . That year, the satellite observations find an accelerated melting of Arctic sea ice, with a loss of 20% of the area of summer sea ice in a year 26 . The observations carried out during the expedition Tara led under the aegis of the European Damocles (Arctic Modelling and Observing developping Capabillities for Long-term Environmental Studies) 27 September 2006 to December 2007 indicate that the changes initiated in the Arctic Ocean are deep and irreversible 28 . In addition, the Greenland has seen its glaciers shrink from 230 to 80 billion tons per year from 2003 to 2005, contributing 10% of current 3 mm annual rise in sea level 29 . A recent study shows an anticorrelation and a bipolar switching between the temperatures of the poles: when a pole warms, cools the other, and the stages of heating / cooling are cycled through a few decades 30 . The link between the two poles would be the Atlantic Ocean . The authors argue that “the recent acceleration of Arctic warming caused by positive reinforcement of the warming trend (due to increased greenhouse gases and other forcings possible) by the phase warming due to multi-decadal climate variability (due to changes in the circulation of the Atlantic Ocean ” . In Antarctica In Antarctica, satellite measurements, made since 1979 show no decrease of surface current, unlike the Arctic ice pack 31 . However, there are a number of exceptional phenomena. Thus, 3 500 km 2 of Larsen B ice (the equivalent of two-thirds the surface of a French department) were fragmented in March 2002, the first cracks appeared in since 1987. This ice was considered stable since 10 000 years 32 . In April 2009, the plate Wilkins, which was once the area of 16 000 km 2 also separated 33 . Polar caps The balance of polar ice caps of Antarctica and Greenland is negative over the last ten years, although some areas of Antarctica thickened due to increased snowfall. The mass loss occurs in coastal areas due to the rapid flow of glaciers into the ocean 3 . Melting permafrost There is a warming and a partial melting of permafrost Arctic. Between one third and half of the permafrost of Alaska is now only one degree of temperature thawing. In Siberia , lakes from melting permafrost are formed, causing significant releases of methane . The release of methane is about 14 to 35 million tons per year on all arctic lakes. The analysis of carbon-14 methane proves that it was frozen for thousands of years 34 . Retreat of mountain glaciers Main article: Retreat of glaciers since 1850 .
A map of the change in thickness of mountain glaciers since 1970. Decrease in orange and red, thickening in blue.
Change in the accumulation of snow at the top of Kilimanjaro : first photo taken Feb. 17, 1993, second February 21, 2000. Kilimanjaro has lost 82% of the glacier during the xx th century and it could be gone by 2020 according to an article in the journal Science in 2002 35 . With few exceptions a note , most mountain glaciers studied are on the decline. Continental glacier retreat is observed an almost generalized from 3 to 4 decades, with a marked increase over the last 20 years 3 . Many studies note 2 document this decline and seek to explain. Such a decline seems quite consistent with a warming climate, however, this assumption is not certain, some glaciers have started to decline in the middle of the xix th century, b 1 , after the Little Ice Age . The advance or retreat of glaciers are recurrent and associated with many factors, including rainfall or phenomenon El Niño are important. For example, the current decline of the Mer de Glace in Chamonix discovered human remains from the Middle Ages 36 , showing that the glacier has chiropractic marketing retreated more than it is today close to a historical period.
The decline of mountain glaciers, notably in western North America, Asia, the Alps, Indonesia, pikalainaa Africa (including Kilimanjaro), and in tropical and subtropical regions of South America, was used as qualitative evidence of rising Plastic Containers global temperatures since the late xix th century by the IPCC in its 2001 report 37 , 38 . The causes of glacier retreat of Kilimanjaro in Africa wedding ring are discussed and are a good example of the complexity of global warming and the caution necessary in the analysis. For some climatologists, the decline is due to a decrease in snowfall since the xix th century, 39 , 40 . For others, global warming is concerned, the fact that tropical glaciers are in the process of regression around the world and the ice of Kilimanjaro have resisted a long drought 4000 years ago 41 . With regard to the Himalayan glaciers, it should be noted the limited data. For example, reliable data are only available for 50 glaciers in India, over 9500 42 . A report by the Indian electronic cigarettes Ministry of Environment, the glaciers of the Himalayas which are the sources of e cigarette the major Asian rivers – Ganges , Indus , Brahmaputra , Yangtze , Mekong , Salween and Huang He – are down. However, this report is cautious in the conclusions 43 : “It is premature to state that the Himalayan glaciers retreating abnormally because of global warming. A glacier is influenced by a variety of physical factors and a complex interconnection of climatic factors. ” Increased runoff seasonality of Himalayan glaciers led to increased agricultural production in northern India during the xx th century 44 . Temperatures in this region increased by 0.15 ° C to 0.6 ° C every 10 years over the last 30 years. Agricultural practices The climate, particularly temperature, have an effect on the date of agricultural crops. In many cases, dates of harvest are regularly advanced, as in Burgundy, 45 , 46 , 47 . Moreover, these phenomena can be described over several decades because the harvest dates were recorded and archived in the past. Such documents are used to determine the temperatures at Denver Divorce Attorney times when the thermometer did not exist or were inaccurate. Global warming since the xx th century is clearly established by the study of these records (for example, the start date of the harvest in Châteauneuf-du-Pape has advanced in fifty years one month 48 ). Fauna and Flora At sea, many species of fish back to the poles. On Earth, there is also a change in the range of different plant and animal species. This change is complex and heterogeneous. In some cases, species and ecosystems face the receding desertification weight loss pills or salinization . Limits of range rising higher elevations, particularly when the range of the species are moving north (or south in the southern hemisphere), which should not hide the fact that Indeed, at least locally, the optimum for a species was down sharply in altitude (where the media are more humid). For example, in California , for 64 plant species whose range was monitored from 1930 to 2010 , the area of climatic optimum of these plants decreased by 80 meters on average 49 . In all these cases, global warming is often suggested as explaining the changes. Paradoxically, locally, due to cold currents resulting from the accelerated melting of the ice cap, winter chills can affect wildlife. So in early February 2011, 1,600 green turtles (endangered species) numb by unusually cold water were stranded on and around South Padre Island (Texas) 50 denver personal injury lawyer . They are more vulnerable to collisions locksmith with boats, their predators and strandings (the first 860 turtles recovered by volunteers, 750 survived and have been subsequently released) 50 . In January 2010, over 4,600 turtles were stranded in Florida 50 . This also applies to terrestrial wildlife. For example, the current extension of the range of the caterpillar pine processionary , which reached Orleans in 1992 and Fontainebleau in 2005, could be due to global warming 51 . The National Museum of Natural History has set up several years of monitoring of species. Time tracking Chicago Criminal Defense Lawyer of common birds (STOC) 52 shows that in twenty years, for example, bird communities in France have generally moved from 100 km to the north 53 . These elements can be of great importance for the strategies of protection and restoration of biodiversity Bankruptcy and green and blue for their travel (including climate corridors where applicable). Thus the national parks primarily positioned in the mountains may not be enough to consider a discrete but important phenomenon of descent of the “optimum” of certain plants 49 which often extend over urban areas and agriculture. Global warming has also resulted in the narrowing of the size of the living species, such as that which occurred Maximum heat Paleocene-Eocene transition . The increase in temperature causes the depletion of oxygen dissolved in water, drought or increased metabolism of ectotherms , such that the vast majority of organizations seems to fit with a lower growth, by an effect shrinkage cascade (the primary producers to consumers ) following a drop of food resources in the food chain 54 . Tropical cyclones
Evolution of tropical storms (blue), hurricanes (green) and major hurricanes ( Category 3 ) (red) in the North Atlantic. Main article: Tropical Cyclone . The scientific consensus in the IPCC 2007 report is that the intensity of tropical cyclones is likely to increase (with a probability greater than 66%). A study published in 2005 , challenging for a second study indicates an overall increase in the intensity of cyclones between 1970 and 2004, the total number of cyclones is decreasing during the same period 55 , 56 , 57 . The number of cyclone intensity 4 and 5 almost doubled in number and proportion between 1970 and 2004 58 . In this study, it is possible that this increase in intensity is related to global warming, but the observation period is too short and the role of cyclones in atmospheric and oceanic flows is not sufficiently known that this relationship can be ascertained. The second study published a year later showed no significant increase in hurricane intensity since 1986, 59 , 60 . Ryan Maue, of the University of Florida , in an article entitled Northern Hemisphere tropical cyclone activity , for its part noted a marked decrease in hurricane activity since 2006 in the northern hemisphere over the last thirty years 61 . He added that the decline is probably more pronounced, action dating back thirty years did not detect the lowest activities, that allow actions today. For Maue is possibly a lower fifty years that we observe in terms of hurricane activity. Furthermore, computer simulations do not allow the current state of knowledge to predict significant changes in the number of cyclones linked to a warming of 1 . Ocean warming and rising sea levels
Rising sea level 62 . There is a warming of the oceans, which decreases with depth. The temperature rise since 1960 is estimated at 0.6 ° C for surface water, and 0.04 ° C for the ocean as a whole 63 . It is estimated that the oceans have absorbed to date from 80 to 90% of the heat added to the climate system 11 , 63 . This warming is contributing 30% to a rise in sea level from thermal expansion, 60% of this rise being due to the melting of continental ice (half of which comes from the melting polar ice caps) and 10% to a flow of inland waters to the oceans 63 . Data are from tide gauges in place since the end of the xix th century, aided in the 1990s by satellite altimetry. Their analysis suggests that the sea level rose during the xx th century a few Cell Phone Accessories tens of centimeters, and continues to rise steadily. It is estimated that sea level has risen 1.8 mm per year between 1961 and 2003 was 2 , 64 and 3.4 mm per year since 1993 63 , 3 . This rise in sea level can also be observed indirectly through its impact on the environment, as is the case in New Brunswick 65 . Main article: Rising sea level . As part of the ARGO system , automatic 3000 tags were distributed in all oceans in 2007 and will monitor the temperature and salinity of the oceans up to 2000 meters. North Atlantic, researchers at Ifremer Brest confirmed warming trends in the surface layers 66 . The curve of the estimated amount of heat in the oceans is updated regularly by the U.S. Weather NOAA 67 Causes
Assuming an additional greenhouse effect
Temperature variation, solar activity and concentration of CO 2 Main article: Greenhouse . The greenhouse effect is a natural phenomenon: some of the radiation infrared emitted from the Earth to the atmosphere is trapped by gases called “greenhouse” , increasing the temperature of the lower atmosphere ( troposphere ). These gases are mainly of water vapor and carbon dioxide. About a third of it was produced by the man 68 . Without this, the surface temperature of Earth would average 33 ° C or below -19 ° C Note 3 , 69 , 70 , 71 The increase in current observed quantities of greenhouse gases such as CO 2 , strengthens the greenhouse effect. Current concentrations of CO 2 in the atmosphere far exceed the rates of 650 000 years. They increased from 280 ppm in 1970 to 379 ppm in 2005, and those of methane increased from 715 ppb to 1774 ppb to 3 . Moreover, the growth rate of the rate of CO 2 in the atmosphere also increases, from 1.5 ppm per year from 1970 to 2000, 2.1 ppm per year between 2000 and 2007 72 . It has been proven by studying isotope of carbon in the air that increased quantities of greenhouse gases is due for more than half of the burning material fossil carbon 11 , e 1 , the other part being mainly due to massive deforestation 3 . The fourth IPCC report has four , 49 billion tons of CO 2 are emitted annually by human activities, as follows: the part due to the energy sector is 25.9%; followed by industry at 19.4%; the forestry sector to 17.4%; agriculture 13.5%; transportation to 13.1%; homes to 7.9%; waste and wastewater to 2.8%. The hypothesis of a link between global mean temperature and the rate of carbon dioxide in the atmosphere has been formulated for the first time in 1895 by the Nobel Prize in Chemistry Svante Arrhenius . Svante Arrhenius showed that increasing the concentration of CO 2 in the atmosphere could increase very significantly the temperature of the planet. He had calculated that a doubling of the CO 2 could cause a warming of 4 to 6 ° C , values consistent with the modeling of the xxi th century . This item shows the length of a scientific theory of global warming 73 . In 1938, the British engineer Guy Callendar , and in 1956 the American physicist Gilbert Plass established and theorized the relationship between the increase in industrial emissions of CO 2 and the first observations of global warming [ref. needed] . In this context, in 1957, the Americans have set up measures of the concentration of CO 2 from the atmosphere in Hawaii . This allowed the American climate scientist Charles Keeling vps hosting in 1961 to produce a first curve confirming a steady increase in the denver martial arts concentration of CO 2 74 , 75 . From 1965 , scientific advisers to the White House warned President Lyndon B. Johnson that the warming could have serious consequences for the United States [ref. needed] . In 1970, the Massachusetts Institute of Technology (MIT) put global warming among the environmental problems of the future the most serious [ref. needed] . But only in 1979 , during the first world conference on climate in Geneva , has been put forward publicly for the first time the international event of the impact of human activity on climate 76 . The increase of the spa covers greenhouse effect induced by the greenhouse gas emissions is estimated at 2.3 W / m 2 . The variations of energy radiated by the Sun during its cycle of activity is ten times lower. The possible influence on cloud formation of galactic cosmic rays modulated by the solar wind is currently under review 3 . Article controversy on global warming hypothesis explains the fluctuations in solar activity Validation of the hypothesis
The supercomputer Earth Simulator has helped to study the origin of global warming. According to the findings of the 2001 scientists of the IPCC , the most likely cause of this warming in the second half of the xx th century would be the “anthropogenic forcing”, that is to say the increase in the atmosphere of greenhouse gas emissions resulting from human activity 77 . The degree of certainty was increased in the 2007 IPCC report, which classifies as very likely that global warming is due to human activity c 1 . According to current forecasts, global warming would continue during the xxi th century , but its amplitude is discussed: according to the assumptions and models used, the forecast for the next 50 years range from 1.8 to 3.4 ° C . Scientific method: modeling
Comparison of changes casino in temperature, observed and simulated with and without anthropogenic factors (relative to the average for the period 1901-1950).
Their conclusions are drawn from the results of experiments with models Digital 78 , e 2 . These models take into account two types of mechanisms 3 : those who are sufficiently well understood to be translated into equations. This is essentially the movement of the atmosphere, radiative phenomena, and hydrodynamics of the ocean circulation. The accuracy of predictions based on these mechanisms is limited by the limitation statiale and time due to computer power and effectiveness of the algorithms used; those whose model is empirical. This is particularly the effect of clouds, the mesh size of the current models do not do to treat them only in a statistical aspect. It is the same for the albedo of the vegetation, which is deducted from compliance measures. Hypotheses to be tested The numerical models were used to estimate the relative importance of various natural and human factors through simulations carried out on supercomputers , to identify the factors behind the sudden rise in temperature. Several hypotheses were tested: cyclical fluctuations of solar activity ; retention of heat by the atmosphere, amplified by the gas greenhouse ; changing the reflectivity of the Earth’s surface – the albedo – the deforestation , expanding deserts, agriculture, the decline of the ice, snow and glaciers, but also by artificial cirrus clouds created by the contrails of airplanes and urban sprawl; emissions volcanic . Some of these causes are of human origin, such as deforestation and the production of carbon dioxide by burning fossil fuels. Some are natural, such as solar activity or volcanic emissions. Results The simulations show that climate warming observed from 1910 to 1945 can be explained only by changes in solar radiation (see Climate Change ) [ref. needed] . However, for the observed warming from 1976 to 2006 (see graph) shows that we must take into account the emission of greenhouse gases of human origin. The models made from 2001 estimate that the anthropogenic radiative forcing is ten times the radiative forcing due to variations of solar activity , although the aerosol forcing is negative. The key point is that the net radiative forcing is positive 11 . In particular, the increase in global average temperature since 2001 is consistent with the predictions made by the IPCC since 1990 on global warming induced by greenhouse gases. Finally, only a warming due to solar activity would not explain why the troposphere would increase its temperature and not that of the stratosphere 11 . Scientific consensus Main article: Positioning of the scientific community to global warming .
A positive radiative forcing is a strengthening of the greenhouse effect and global warming, a negative radiative forcing causes cooling (increasing the albedo ). This corresponds to calculations taking into account the concentrations in the atmosphere has 5 . In its 2001 report, the IPCC concluded that greenhouse gas anthropogenic “play an important role in global warming” 79 . In 2003, the American Geophysical Union states that “natural influences can not explain the rapid rise in surface temperatures of the earth” 80 . On June 7, 2005, the science academies of the countries of G8 note 4 and those of the three largest countries in the developing oil-consuming note 5 have signed a joint declaration to London , saying the talks by some to doubt the place climate change no longer justifies inaction on the contrary, we must “immediately initiate” a global action plan to counter this global threat 81 . Finally, in 2007, the fourth IPCC report , said that the probability that global warming is due to human activities is greater than 90% c 1 . Many scientists even believe that this report is not clear enough and should now an international program to reduce drastically the two main sources of greenhouse gas emissions, road transport and coal 82 . Critics of the hypothesis of human origin Controversy on global warming Although there is a strong consensus in the scientific community on the predominant role of human activity in global warming of the last half-century personalities contesting all or part of this thesis and attribute the warming to causes natural 83 , for example related to the natural activity of the Sun. This assumption is not adopted by the Academy of Sciences French 3 . In addition, reviews and controversy also address the consequences of global warming (see Further warming below) and actions to fight against him (see States’ response below). Projections
The IPCC distinguishes the predictions of climate projections climate. Climate forecasts are the result of an attempt to estimate the actual evolution of the climate in the future (at time scales seasonal, interannual or long-term, for example), and are generally of a probabilistic nature. Climate projections are based on climate models and respond to various scenarios of greenhouse gas emissions, based on assumptions about economic and technological developments to come. However, these assumptions can be realized or not, the projections are subject to considerable uncertainty was 6 . Climate models The projections by scientists of the future climate is possible through the use of mathematical models treated by computer on supercomputers 84 . These models, known as general circulation , based on the general laws of thermodynamics and simulate the movement and temperature of air masses and ocean. Latest also take into account other phenomena such as the carbon cycle . These models are considered valid by the scientific community when they hcg diet plan are capable of simulating known climate variations such as seasonal variations, the phenomenon El Niño , or the North Atlantic Oscillation . The latest models adequately simulate temperature variations during the xx th century. In particular, the simulations conducted on the climate of the xx th century without integrating human influence do not account for global warming, while those including this effect are in agreement with observations 11 . Computer models simulating climate are then used by scientists to develop scenarios of future climate, but also to identify the causes of global warming today, comparing the observed climate changes with the changes induced in these models by different causes natural or human. These models are subject to uncertainties which mathematics, computer science, physics, etc.. The three main sources of uncertainty identified by climatologists are: modeling of clouds ; simulation of phenomena of smaller scale , such as cell thunderstorm , or the effect of terrain on atmospheric circulation; modeling of the interface between ocean and atmosphere. More generally, these models are limited in part by the capabilities of computers today, and know their designers on the other hand, the climate and the phenomena to be modeled is highly complex. The scale of investment necessary budget are an important aspect of research in the field of global warming. Despite these limitations, the IPCC considers climate models as tools to provide relevant writers of useful changes in climate. Continued global warming
For climatologists grouped within the IPCC , the increase in temperatures is expected to continue during the xxi th century . The magnitude of the expected warming is most likely to 1.8 to 3.4 ° C . The magnitude of warming is uncertain, the simulations take into account: uncertainties related to the models (see above); t shirt printing uncertainties in the behavior of mankind in the xxi th century . To take into account this parameter in their projections, the IPCC climate scientists have used a family of 40 emission scenarios of greenhouse gas emissions detailed in the report Special Report on Emissions Scenarios (SRES) 85 . In some scenarios, the growth of human population and economic development are strong, while the energy sources are mainly fossil. In other scenarios, one or more of these parameters are modified, resulting in consumption of fossil fuels and production of greenhouse gases reduced. The scenarios used as a working hypothesis for the development of the third IPCC report (2001) do not take into account the possibility of an intentional change in emissions of greenhouse gases worldwide. Uncertainties related to the operation of the models are measured by comparing the results of several models for the same scenario, and comparing the effects of small changes in emission scenarios in each model. Variations in climate simulations are causing a dispersion of forecasts of around 1.3 to 2.4 ° C , for a scenario (demographic growth, “global energy mix,” etc. .) given. The type of scenario has an impact of about 2.6 ° C global warming simulated by these models and explains much of the uncertainty existing as to the magnitude of future warming. Projections of temperature increase for the year 2100 given by the IPCC (SPM report of 2007) range from 1.1 to 6.3 ° C . IPCC experts are refining their projections giving values considered “best estimates”, which reduces the range of 1.8 to 4.0 ° C . And eliminating the A1F1 scenario, considered unrealistic, the temperature increase would be between 1.8 and 3.4 ° C . The four families of scenario 86 , 87 , 88 of the fourth report and forecast increases in global average temperatures in 2100 Source: IPCC 89 More cost objectives Environmental objectives more Globalization (World homogeneous) A1 rapid economic growth (groups A1T/A1B/A1Fl) 1.4 to 6.4 ° C B1 Global Environmental Sustainability 1.1 to 2.9 ° C Regionalization (World heterogeneous) A2 Economic Development with a regional focus from 2.0 to 5.4 ° C B2 Local Environmental Sustainability 1.4 to 3.8 ° C IPCC scientists believe that these scenarios are the best projections currently available, but they are always subject to adjustments or challenged in as and scientific advances. They consider it necessary to obtain more realistic models and better understanding of weather and associated uncertainties. However, many climatologists believe that the short-term improvements made to the climate models do not fundamentally alter the results, namely that global warming will continue and that its magnitude will be more or less depending on the amount of greenhouse gas gases emitted by human activities during the xxi th century , and that due to the inertia of the climate system on a global scale. Some scientific papers show that 1998 was the warmest in the history of meteorology note 6 , that the warming is accelerating – 0.8 ° C in a century, of which 0.6 ° C of the thirty recent years – but also from the analysis of marine sediments, the heat current is at the top of the temperature scale since the beginning of the Holocene , that is to say, since 12 000 years 90 . Predicted environmental consequences
The models used to predict future global warming can also be used to simulate the effects of global warming on other physical parameters of the Earth, such as ice sheets, precipitation and sea levels. In this area, a number of consequences of global warming are the subject of a consensus among climate scientists. Rising waters One of the consequences of global warming on which scientists agree is a rise in sea levels . Two phenomena generate this elevation: increasing the volume of water due to its warming ( thermal expansion ); the additional water from melting of continental glaciers and ice caps. This phenomenon has a long-term glacier melt is measured across several decades, and the polar ice caps over centuries or millennia b 2 . As for temperatures, uncertainties in sea level are related to models on the one hand, and future emissions of greenhouse gases, on the other. The increase between 1993 and 2003 is estimated at 3.1 mm per year (plus or minus 0.7 mm ) 11 , 63 . The projected rise in sea level in 2100 is from 18 to 59 cm , according to the fourth report of the IPCC was 7 . This is probably a minimum estimate because the predictions of the IPCC are based solely on future warming of the ocean and melting of mountain glaciers expected, excluding the phenomena related to a possible instability of the polar caps, recently emphasized 63 . A rise in the water a few inches is not very visible impact on the rocky shores, but can have very significant effects on the coastal flat sediment dynamics: in these regions, which are in dynamic equilibrium, the rising waters builds the capacity erosion of the sea, and so overall balance moves towards a resumption of the erosion that is pushing the ribs. The rise in average sea level has much larger effects than the simple translation of the coastline to the contours. Precipitation According to the latest report of the IPCC , increased precipitation at high latitudes is very likely while in the subtropics, is expected to decline, continuing a trend already noted e 3 , although other experts temper this, saying data too scarce and incomplete in order to identify a trend upward or downward 17 . Studies indicate that by 2025, one third of the world population could be in a state of water stress 91 ; warming would sometimes a positive, sometimes negative effect, the balance between the two depending in the counting mode adopted 92 . Thermohaline circulation The thermohaline circulation refers to the movement of cold water and salt to the ocean floor that take place at high latitudes of the northern hemisphere. This would, with others, responsible for the renewal of deep ocean and the relative mildness of the climate in Europe. In case of global warming, the engine that drives the ocean currents would be threatened. Indeed, the current gain their kinetic energy in the deep water cold and salty and therefore dense in the depths of the Arctic Ocean. However, the increase in temperature should increase evaporation in the tropics and rainfall in the regions of higher latitude. The Atlantic Ocean, warming, would receive more rain, and in parallel the ice cap could melt partially (see Heinrich Event ) 93 . In such circumstances, a direct result would be a massive influx of fresh water around the poles, resulting in decreased marine salinity and thus the density of surface waters. This may prevent them from diving in the ocean depths. Thus, the currents like the Gulf Stream could slow or stop, and do not provide current heat exchange between the best web hosting equator and the temperate zones. For the xxi th century , the IPCC in its 2007 report considered as a likely slowdown of the thermohaline circulation in the Atlantic, but very unlikely that a sudden change in circulation was 8 . Potential disruption of the Gulf Stream Main article: Disruption of the Gulf Stream . One theory is a possible shutdown of the Gulf Stream, due to global warming, could lead to a iphone ringtones significant drop in temperature or an ice age in Europe and in regions at high latitudes. Indeed, Europe is at the same latitude as Quebec, and Detlef Quadfasel study published in Nature in December 2005 shows that part of the climate difference seems to lie in the fact that Europe benefits from the “heat input of the Gulf Stream 94 . The equator, in contrast, accumulate while the heat thus stimulating the formation constant of hurricanes causing extensive rainfall. This hypothesis of a cooling of Europe that would follow Unlock iPhone global warming is not validated. Indeed, there is no evidence that the Gulf Stream is the only cause mild winters in Europe. Thus, Richard Seager published in 2002 a scientific study on the influence of the Gulf Stream on the climate 95 . His conclusions are clear: the effect of the Gulf Stream is, he says, a myth and has a minor effect on the climate in Europe. The difference in winter temperatures between North America and Europe is due to the prevailing winds (continental cold north wind on the east coast of North America and oceanic wind from the west in Europe) and the configuration of the Rocky Mountains . Ice and snow cover Scientists from the IPCC provide for the xxi th century a decrease in snow cover, and removal of ice shelves . The glaciers and ice sheets of the Northern Hemisphere should also continue to decline, glaciers located within 3400 m of altitude that can be brought to disappear for two . However, the evolution of the ice sheet Antarctic in the xxi th century is more difficult to predict. In 2006 a team of American researchers has identified a link between human activity and the collapse of platforms of ice in Antarctica 96 . The local warming are due to a change in prevailing wind direction, this change is itself due to the increase of the concentration of the air in greenhouse gas emissions and the degradation of the ozone layer in Antarctica because of the CFC of human origin 97 . However, a letter to the journal Nature , the warming observed only locally. Indeed, the Antarctic climate is in general colder and ice coverage is expanding, the temperature increases in these areas very cold be conducive to increased snowfall thus ultimately to increased volumes of ice 98 . However, the amount of Antarctic ice dumped into the seas rose 75% during the ten years prior to 2008 98 . This phenomenon is likely to increase due to the disappearance of the ice which then ceases to oppose an obstacle to the discharge of glaciers into the ocean 32 . Abrupt or irreversible consequences, and prospective According to the IPCC, “anthropogenic warming of the planet could cause certain effects that are abrupt or irreversible, depending on the rate and magnitude of climate change” is 9 . It is expected an increase in sea level of several tens of centimeters by 2100, but over the centuries and millennia following the partial melting of polar ice caps could raise several meters sea level, flooding low lying coastal areas Some low-lying islands and deltas to 9 . Approximately 20-30% of species assessed so far are likely to be exposed to increased risk of extinction if the increase in global average warming exceed 1.5 to 2.5 ° C (from 1980 to 1999) . With an increase in average global temperature higher by about 3.5 ° C , model projections indicate extinctions (40 to 70% of species assessed) around the world a 9 . In May 2008, the U.S. scored the Polar Bears of Alaska on the endangered species list 99 . Warming could lead to a rebound effect irreversible on a human scale of time if it starts forest fires [ref. needed] and an important degassing of methane from permafrost and the seabed. The amount of methane being released from the permafrost melting is about 14 to 35 million tonnes per year. It is estimated that this amount will rise by 100 to 200,000,000 tons per year by 2100, leading in itself to a temperature rise of about 0.3 ° C. Over the next few centuries, 50 billion tons of methane could be released by the lakes thaw Siberia 34 . Indirect effects on the soil and subsoil, including collapse of underground cavities ( career (geology) s , old dugouts, saps of war, marl pits , etc..) are expected (3000 municipalities are subject to this risk in France, excluding risk of “ mining subsidence “according to INERIS 100 . A “Plan cavities” (about the cna certification risks or not climate change) is being considered in France as INERIS. The water is warmer and more acidic, and more intense winter rains, as well as thermal shock and movement of groundwater may exacerbate this risk increased by the end of the century. Some, including climatologist James Hansen, believe that “Earth may have exceeded the danger of CO 2 , and the sensitivity of global carbon dioxide is much greater than that used in models 101 . ” Optimistic and forward-looking visions coexist less optimistic in 2009: some insist that technical solutions exist, and it only remains to apply (the houses could be isolated, and scrabble word finder they produce more electricity n ‘consume, transport control, the cities could be more independent and clean up the air 102 ). Others – while inviting to apply these
solutions as quickly or even decline, user-friendly sustainable – réalertent , found that of 1990 to 2009 , the trend has been the realization of the high ranges of emission of greenhouse gases, leading disaster scenarios, the IPCC 103 , and consider that it is time to stop talking about “change” to describe a catastrophe 104 . Very long-term phenomena The majority of climatologists believe that the phenomena caused by the emission of greenhouse gases will continue and grow. The third report of the IPCC focuses in particular on the following: Some greenhouse gases have a long life expectancy, and therefore influence the greenhouse effect long after they are issued (lifetime in the atmosphere about 100 years for CO 2 105 ); by the inertia of the climate system, global warming will continue after the stabilization of the concentration of greenhouse gas emissions. This warming, however, should be slower; inertia, even greater mass that rising ocean sea levels will continue even after the stabilization of global mean temperature. The melting of ice caps, like that of Greenland , are phenomena that take place Judaica Bat Mitzvah Gifts over hundreds or pro flight simulator even thousands of years b 2 . Recent observations in the Arctic under the aegis of the European Damocles (Arctic Modelling and Observing developping Capabillities for Long-term Environmental Studies) have created a surprise in the scientific world. Indeed, they show a significant difference with the predictions from different models and which are based on the findings of the IPCC : this results in a marked acceleration effects due to the increase in greenhouse gas emissions in the Arctic ( complete melting of sea ice in summer by in 2020) 106 , 107 . Feedback The scientists call feedback actions back on the climate system itself. These feedbacks are positive when the global warming induced phenomena contributing themselves to increasing global warming, and negative when the induced phenomena contribute to reducing global warming. Such feedbacks have already been observed in previous global warming at the end of an ice age, the climate can, in a few years to warm up several degrees. The main positive feedback are: the release of methane: the methane (CH 4 , which is none other than natural gas, a few “impurities” close), is a greenhouse gas 23 times more warming than CO 2 . It is formed when the decomposition of organic matter is made with a lack of oxygen, and under the action of bacteria, a process called anaerobic digestion road rage . Moist soils (marsh) are very conducive to the creation of methane, which is then released into the atmosphere (this can lead to spontaneous combustion and can be seen wisps ). If the ground is frozen, methane remains trapped in the ice in the form of methane hydrates . The soil of Siberia and is a huge reservoir of methane (probably too diffuse to be exploited commercially): according to Larry Smith, Department of Geography, UCLA , the amount of methane in the Siberian soil would be 70 billion tonnes, a quarter of the methane stored on the surface of the planet 108 . If the soil warms, ice melts and releases methane already present initially, which results in a stronger greenhouse effect, and hence a runaway global warming, which melts the ice faster. Also referred to as carbon bomb ; slowing down and changing ocean currents: the ocean captures today one third of CO 2 emitted by human activities. But if the ocean currents slow down, the surface layer can become saturated with CO 2 and could not pick more like today. The amount of CO 2 that can absorb a quart of water decreases as the water warms. Thus, large amounts of CO 2 can be leached if the ocean currents are changed. In addition, the accumulation of CO 2 in the oceans led to the acidification of the latter, which affects the marine ecosystem and can induce a long-term release of CO 2 . The engines of ocean circulation are of two types: water approaching the poles cools and becomes denser. In addition, seawater that freezes rejects its salt in liquid water (ice consists of fresh water), becoming the neighborhood ice caps even more dense. This water then plunges and feeds the pump warmer water from the surface is drawn. The bottom water (cold) back in the areas of the tropics and / or equatorial and heats up, this in a cycle of more than 1000 years. If the ice caps melt, the pump stops: in fact, the water plunges from the cap instead of chilled water from the tropics. A similar effect is observed if precipitation increases in high latitudes (as provided by the models): the water is fresh water plunge of rain. Ultimately, a strong disruption of Gulf Stream is possible; Main article: thermohaline circulation . the variation of albedo : Currently, snow and ice from polar regions reflect the sun rays. If melting of the snow or the ice, the sun’s rays are more absorbed, causing an additional warming of these regions and melting intensified, amplifying the phenomenon. The negative feedback is more uncertain: the development of vegetation in some areas, global warming could be conducive to the development of vegetation, which is a carbon sink , contributing to limit the increase in greenhouse gas emissions; the role of water vapor: global warming could increase the formation of clouds contributing to reflect more sunlight. However, water vapor is itself a greenhouse gas emissions and the final outcome of increased water vapor in the atmosphere is quite difficult to predict. Consequences of global warming on humans and the biosphere Beyond a direct, physical and climate, global warming, it will affect the ecosystem , especially by changing biodiversity . Scientists are beginning to offer considered fairly reliable projections of the future of biodiversity on the basis of five factors: the degradation and habitat destruction, climate change, the availability of nutrients, overexploitation of biological resources and invasive species . The Convention on Biological Diversity (CBD) in 2010 proposed scenarios facing biodiversity responses to global payday loan change. These forward-looking tools from statistical models, experiments and trends are intended to help the dialogue. From the work published in scientific journals, peer-reviewed, the CBD ( via DIVERSITAS, UNEP-WCMC) has produced these “ biodiversity scenarios “with the participation of about 40 experts, including eight French 109 , 110 . In France, the Biodiversity Foundation (KBF), under the flagship “modeling and scenarios of biodiversity” was translated into French the technical specifications 111 . Worldwide, according to the IPCC , the ability of many ecosystems to adapt naturally is likely to be exceeded by the combination 112 unprecedented: climate disruption: floods , forest fires , droughts , insects, ocean acidification ; global change: changes in land use ( deforestation , dams , …), pollution , overexploitation of resources. The ensuing natural imbalance could lead to the disappearance of several animal and plant species. This is a concern that States such as France 113 , are beginning to consider. For all human populations, these effects “physical” and “green” will have a major impact. The overwhelming complexity of ecological systems, economic and social affected by global warming does not make numerical predictions as to the physical modeling of the Earth. Biological and ecological level, a scientific consensus has been reached on the following: some species may see (and possibly temporarily) their population and range increase (eg for the yellow-bellied marmot 114 ), but the overall global warming in terms of biodiversity will be negative in a number of Studies 115 , 116 , 117 and according to the consensus of the Fourth Report of the IPCC considering the loss of 40 to 70% of species assessed at 9 ; Some natural systems are more affected than others by global warming. Systems are the most sensitive: the glaciers , the coral reefs , the mangroves , the boreal forests and tropical, polar and alpine ecosystems, prairie wetlands. The coral bleaching was observed for the first time since 1979 in the Caribbean 118 . This phenomenon has grown steadily in space and time scales still larger, for example, across the Indian Ocean in 1998 119 . If the warming continues at its current rate, there are fears a mass extinction of coral reefs around the globe from 2015 / 2020; damage to natural systems, whether by their geographical extent or intensity will be proportional to the intensity and speed of global warming. Negative consequences for humanity The IPCC provides major negative consequences for humanity in the xxi th century: a decrease in potential crop yields in most tropical and subtropical areas; a decrease of water resources in most tropical and subtropical dry regions; a decrease in the flow of water sources from melting ice and snow, following the disappearance of the ice and snow. an increase in extreme weather such as torrential rains, storms and droughts , and increased the impact of these phenomena on agriculture; an increase in wildfires during hotter summers; the engagement ring extension of areas infested with diseases such as cholera or malaria . This risk is greatly minimized by the specialist Professor Paul Reiter 120 but the Government of the United Kingdom pointed out that this teacher has chosen to ignore all the recent reports that contradict 121 ; increased flood risk, both because of rising sea levels and climate changes; higher energy consumption for air conditioning; lower crop yields to prospective middle and high latitudes (in the case of a strong warming). Positive consequences for humanity They are also associated with warming under xxi th century: lower winter mortality in mid and high latitudes; a possible increase of water resources in some dry ppi claim tropical and subtropical regions; an increase in potential crop yields in some regions at mid-latitudes (in the event of a global low); the opening of new sea routes in the Canadian Arctic due to melting ice in the passage of the Northwest 122 . Consequences in France As regards France, the rise in temperature may increase the number of heat waves in 2100 123 . While the number of hot days is currently 3 to 10 per year, it could amount to an average of 20 to 40 in 2100, making the ordinary extraordinary heatwave of 2003 124 , d 3 . Precipitation would be greater in winter, but lower in summer. Regions with lengths of more than 25 consecutive days without rain, currently limited to the southeast of France, would extend to the western half of the territory b 3 . Vegetation would experience a rise towards the north. The spruce could disappear from the Massif Central and the Pyrenees. The oak tree , widespread in eastern France, its area would reduce the Jura and the Vosges, but the maritime pine , currently located on the west facade, extend over the western half of France and the oak s expand in the southern third, marking a stretch of the Mediterranean climate b 4 , 125 . Cultures of the Mediterranean south, such as that of the olive tree , could locate in the Rhone Valley. We can now find olive trees as a tree ornament throughout the southwest side of the Atlantic Ocean , until Vendée . By cons, for lack of sufficient water, the cultivation of corn would be limited to the north and northeast of the country. Cereals would increase performance if the temperature rise does not exceed 2 ° C. By cons, if exceeded, crops would have difficulty adapting and could be anticipating trouble agricultural b 5 , d 4 . The snow will be less abundant, leading to lower water rivers, but also economic difficulties for the economy in the mountains. For example, ski resorts located less than 1500 m above sea level would be forced to close their tracks and convert to b 6 . Human consequences of global warming
Related article: Issues of global warming . About global warming, the American Academy of Sciences noted in a report in 2002 one hundred and twenty-six : “It is important not to adopt fatalistic attitude in the face of threats posed by climate change. (…) The companies have had to deal with climate change gradual or abrupt, and for millennia have adapted through various reactions, such as shelter, develop irrigation or migrate to more hospitable areas. Nevertheless, because climate change is destined to continue in the coming decades, denying the possibility of abrupt climate events and minimize their impact in the past could be costly. “. Impact on coastal regions Rising sea level is estimated at between 18 and 59 cm by 2100 the fourth IPCC report was 7 . This increase is in addition to phenomena that are not related to climate and causing a depression of the soil: sediment load in river deltas, groundwater pumping, extraction of oil and gas … The populations of some islands of the Pacific Ocean or the Indian Ocean , such as islands Maldives and Tuvalu , are directly threatened, as a part of their territory could end up under water. But all the people living in coastal areas (more than five hundred million people) may find their degraded environment (coastal erosion, saline aquifers, loss of wetlands, permanent flooding) 63 . In France, studies are conducted to assess the impact of rising waters on the coast by 2100 and to consider adjustments 127 . Agriculture and Fisheries The increase in the evaporation should increase the local rainfall winter, except in the Mediterranean countries would intensify drought b 7 , in a context where violence and / or the frequency and severity of weather 
conditions could grow. In temperate zone (outside the areas dry could become even more) and circumpolar at first, the combination of warming and the increase of CO 2 in air and rain could increase the productivity of ecosystems . Agriculture Northern United States, Canada, Russia and the Nordic countries might benefit b 8 , but signs of forest decline already seem visible in these areas. Also unknown from when marine ecosystems react negatively to the ocean acidification arising from the dissolution of increasing amounts of CO 2 . Organisms such as yeast or plants (eg Arabidopsis thaliana ) are – with a single protein ( histone H2A.Z) for Arabidopsis – sensitive to temperature variations of less than 1 ° C , sufficient via this protein change the winding of the DNA itself, which controls access to the DNA of certain molecules that inhibit or activate several dozen genes 128 , 129 . This should help to better understand some of the effects (of genes) of global warming. The European Economic and Social Committee in Opinion 130 of 3 February 2009 noted that comparative studies conclude that a balance of organic farming on average better (in terms of the consumption of raw materials and energy in terms of carbon stored or greenhouse gas emissions) than of Agriculture called conventional 131 , even taking into account the lower yields of organic farming, which justified the German government, integration among means to fight against climate change 132 ). CESR also remember that agriculture could be reoriented and adapted according to various experts and NGOs, also help to buffer or slow down the effects of warming ( Cool farming ) 133 ). The committee does not cite biofuels as a solution, citing climate scientist Paul Crutzen who said that emissions of nitrous oxide-induced culture and biodiesel, are sufficient, under certain conditions to the methyl ester of rapeseed may affect conditions worse than those of diesel fuels made from oil 134 . The Committee 135 , is also the issue of traditional fertilizers and wonders “if the full use of plants, as provided in the context of second generation biofuels, will not harm the objectives set for development of the humus layer ” , that is to say, contribute to further deplete the soil organic matter. The committee is the issue of life cycle assessment of biofuels citing a comparative study of the Empa 136 which concluded that to cover 10 000 km a Volkswagen Golf required, with the yields observed in Switzerland, 5265 m 2 of rapeseed ( biodiesel) against 37 m 2 of solar panels (or 134 times less). Forest and forestry According to a study by Thomas Veblen 137 , professor of geography at the University of Colorado , co-author with the American Institute of Geophysics, conducted on forest plots in the western United States for the periods 1955/1994 and 1998 / 2007, 30 years, an average warming of 0.5 ° C has already doubled the mortality rate of trees in large forests of the American West, promoting drought and pest outbreaks (including bark beetles that have destroyed about such 1.4 million hectares of pine in the north-western Colorado). In this study, the lack of snow-induced water deficit and longer summer droughts, fires with multiplication, raising fears of cascading impacts on wildlife and ecosystems. The increase in mortality affects trees (deciduous and coniferous) of all sizes and different species and at all altitudes. In the American Northwest and southern British Columbia (Canada), the mortality rate in older coniferous forests doubled in 17 even years (ie one and half times faster than the increase in mortality California groves of trees where the rate was doubled in 25 years). The acceleration of mortality was lower in the forests of the west does not bordering the Pacific (in Colorado and Arizona), but “ a doubling of the mortality rate will eventually halve the average age of groves of trees, resulting in a decrease in their average size , “said T Veblen also fears that a lower fixing CO 2 from the atmosphere and that calls to “consider new policies to reduce the vulnerability of forests and people” including limiting residential urbanization in vulnerable areas. In France, according to forecasts by the INRA, many species will not survive in the southern half of France and several pests of trees could continue to move north. Access to the Arctic Ocean A decrease in Arctic ice has opened up new trade routes for vessels 138 , and make available resources underwater oil or raw materials, but with a negative impact on many species, such as plankton or fish high commercial value. Access to these materials now available in areas likely to be source of conflict between countries bordering STD Testing the Arctic Ocean to 5 . Thus, the United States and Canada when they protested, August 2, 2007, Russia planted its flag on the seabed under the North Pole . Economy A report of 700 pages of Sir Nicholas Stern , British economist, believes that global warming would entail an economic cost of 5,500 billion euros 139 taking account of all generations (present and future) have to suffer the consequences . In 2007, for the first time, the World Monuments Fund (WMF, World Monuments Fund ) introduced the climatic changes in the list of threats to 100 sites, monuments and masterpieces of architecture at risk, other main threats are the wars and political conflicts, and uncontrolled industrial and urban development. Health Health consequences of climate is being feared: the fourth IPCC report highlights some of the effects on human health, such as “heat-related mortality in Europe, infectious disease vectors in various regions and allergies to pollen middle and high latitudes of the northern hemisphere ” c 2 or the emergence or reemergence of infectious diseases 140 . Climate change will alter the geographical distribution of some infectious diseases was 10 . High temperatures in hot regions could reduce the spread of the parasite responsible for schistosomiasis . But the malaria reappeared in the north and south of the tropics. In the U.S., the disease was generally limited to California, but since 1990 outbreaks have appeared in other states such as Texas, Florida, as well as New York. It is also re-emerged in areas where it was uncommon, as southern payday loan Europe and Russia or along the Indian Ocean. There is also evidence that mosquitoes and the diseases they transmit have gained altitude of 6 . In temperate climates, global warming would reduce the number of deaths by cold or respiratory disease, but increases mortality during summer heat waves. It is unclear what the overall balance, and if a decrease in life expectancy will result in d 7 . The Institute of Health Surveillance (InVS) sought the key risks for metropolitan France and routes of adaptation options for monitoring and research 141 and published in late 2010 a Position Paper 140 on the subject. Global geopolitical instability According to a 2003 report commissioned by the Department of Defense U.S. 142 and according to a 2007 report by the United Nations Programme for Environment (UNEP), global warming could lead to global destabilization, with risks Civil War 143 . Global warming and its influence on environmental change, coupled with political or economic factors are taken into account in the study 144 , 145 possible forced migration of population. Interaction with the crisis of 2008-2009 In 2009, the International Energy Agency (IEA) notes 146 , 147 – because of the crisis – a decrease of energy consumption, but also a decline in investment in energy savings (in less than one fifth in 2009), The IEA fears a further increase induced by a possible economic recovery. According to the agency should invest 10,500 billion by 2030 to “carbonize” the economy to limit the impact on climate (the script is 450 ppm CO 2 should not be exceeded for the warming does not exceed 2 ° C in 2100). With the continuing trend scenario ( 1.5% per year in energy consumption from 2007 to 2030, + 40% in total) is an average increase of 6 ° C could conclude the 21 th century 146 . Responses of states, communities, businesses, citizens face the threat of climate change
Central heat and wind . Peine , Lower Saxony , Germany . The reality of the risk and the phenomenon is now almost a consensus. The author of the Stern Review , Nicholas Stern , in 2006, acknowledged himself to have underestimated the magnitude of 148 , 149 : “The growth of CO 2 is much stronger than expected, the absorption capacity of the planet are reduced and the speed of climate change is faster than envisaged. ” Address the problem, three approaches are complementary: the fight against the emission of greenhouse gas emissions, carbon sinks , and adaptation . The international effort was initially aimed at reducing the CO 2 gas (long life), so that urgent action on short-term pollutants (including methane , the ground-level ozone and “black carbon” ) could better reduce the warming of the Arctic 150 . The reduction of CO 2 is also important, but its effects will be felt in the longer term (after 2100). The prospective enlighten governments, companies and individuals who, through knowledge of trends, can make decisions more relevant policy and strategy to limit the impacts of climate change. The reports of the IPCC are the main basis of information and discussions, including through the Kyoto Protocol and its aftermath ( Bali , December 2007, …). The expected increase of 1.5 to 7 ° C for the next century, may be less severe if environmental measures were taken or that a real competitor to fossil fuels emerged. Despite successes in the field of renewable energy , the nuclear and especially a change in lifestyle and consumption, research has not offered an alternative to short-term fossil fuels. Wind power , hydropower , geothermal , solar , biogas, energy turbine , fuel cell , nuclear energy , geological storage of carbon dioxide are still rapidly developing. The source of energy savings – the negawatts – is still considerable. Civil society also offers answers, including through campaigns and actions of lobbying of NGOs and local associations. In France, the NGOs to protect the environment and the associations concerned have joined together in the Climate Action Network (RAC). Global warming could lead to a more unstable weather (heat waves or cold, flood or drought , storms and cyclones ) 151 . In addition, according to the IPCC , the ability to adapt naturally to many ecosystems is likely to be exceeded, causing massive the extinction of species , by combining 152 unprecedented: causing climate change: forest fires , likely increase the intensity of hurricanes , ocean acidification , species movements, melting glaciers and polar ice caps, major geopolitical and economic impacts; human pressure amplified by overpopulation : regression and land degradation ( deforestation , dams , new crops and genetically modified organisms ), pollution , overexploitation of resources. Kyoto Protocol Main article: Kyoto Protocol . The Framework Convention of the United Nations on Climate Change was signed at the 1992 Earth Summit in Rio de Janeiro . It takes effect March 21, 1994. The signatories to this agreement agree on the objective of stabilizing the concentration of greenhouse gases in the atmosphere at “a level that would prevent dangerous anthropogenic interference with the climate ” 153 . Developed countries have an objective of reducing their emissions of greenhouse gas emissions by 2010 to 1990 154 , this objective is not legally binding [ ref. desired] . In 1997, the signatories to the Framework Convention adopted the Kyoto Protocol, whose novelty is to set binding reduction commitments for developing countries so-called Annex B (industrialized countries and in transition) and put in place mechanisms words “flexibility” (market of permits, joint implementation and clean development mechanism) to fulfill this commitment. The Kyoto Protocol comes into force on 16 February 2005 following ratification by Russia [ ref. desired] . In July 2006, the Kyoto Protocol is now ratified by 156 States 155 . The United States and Australia (see below) are not signatories. The U.S. , however, are the second transmitter global greenhouse gas emissions with about 20% of greenhouse gas emissions 156 . Countries of Annex B are committed to reduce their emissions of six greenhouse gases ( CO 2 , CH 4 , N 2 O, SF 6 , HFCs, PFCs) of 5.2% in 2008-2012 compared at 1990. After the victory of Labour in Australian election of November 24, 2007, the new Prime Minister Kevin Rudd announced that it has ratified the fender flares Kyoto Protocol 157 . Countries in developing a strong contributor to shows such as the India , 5 th transmitter world and China, a re issuing 156 , have no reduction targets because they were considered insufficiently developed and because their levels reduced emissions to population are extremely low [ ref. desired] . European Union Main article: European sustainable development policy . The European Union launched in 2005 the EU ETS emission allowance ( 1 st market “permit binding” in the world). In October 2006, the European Economic and Social Committee (EESC) activates its Sustainable Development Observatory (SDO) 158 . The European Commission published June 29, 2007 a ” Green Paper “on the climate change adaptation of the European Union 159 . It promotes both adaptation and mitigation, improved knowledge (including the needs and costs of adaptation – See 7 th Framework Programme for EU Research (2007-2013)) strategies and exchange best practices between countries, new insurance products (“weather derivatives”, “catastrophe bonds,” the adaptation of the European insurance market (see Directive “Solvency II”) and funds “natural disasters” as well as agriculture and fisheries policies, with the development of internal solidarity of the EU and with countries outside affected. 50 million euros are reserved by the Commission for 2007-2010 to promote dialogue and support for mitigation and adaptation targeted in poor countries. The Directive on the European system of trading emissions in 2008 should be amended to include such emissions of aviation . This was refused by the Council but should still be included by 2012 160 . The proposed emission limits on cars ( 130 g of CO 2 per km 161 ) was approved by the European Parliament the second half of 2008 162 . New measures must be taken to reduce this emission rate to 120 g CO 2 per km. France has also published a “National Strategy for Adaptation to Climate Change” in July 2007 note 7 and consider appropriate governance 163 , especially in the Grenelle Environment . The EU has resources onshore and offshore (already 66% of the installed wind power worldwide in 2006, mainly in Denmark produces almost 40% of its electrical power) to the United States (16%) , India (8%) and Japan (2%) in solar technologies and third 164 of the nuclear world. This makes it less dependent on fossil fuels as China and the United States. France, the country most nuclearized , remains far from the record of 1961 when 51% of its electricity came from renewable (hydroelectric) 165 . The EU also encourages all stakeholders to prepare for adaptation to climate change 166 . Regions and communities in Europe and the United States could cooperate on climate: Bresso (the President of the Committee of the Regions ) and Elizabeth B. Kautz (President of the U.S. Conference of Mayors, the mayors official organization of some 1,200 cities with over 30,000 inhabitants have the United States, which is a kind of equivalent of the European Covenant of Mayors , which brings together in 2010 2000 cities, 25 cities and 100 regions), signed May 5, 2010 a “ Memorandum of Understanding and Cooperation “in the fight against climate change 167 . United States [ change ] Main article: Environmental Policy in the United States . Second largest polluter after China 168 , the United States via the administration of George W. Bush refused to resubmit the treaty in July 2005 for ratification regards it as a brake on the economy and the fight against global warming must be done car transport not with a simple reduction in greenhouse gas emissions, but through better management of their issuance. Many states of the United States , like California , have nevertheless taken steps federal restrictions on greenhouse gas emissions. Fight against global warming in the United States [ change ]
Wind turbines in Texas . Since 2001 , the states of Texas , from California , from New Hampshire , have introduced a control gas emissions for various industrial and energy sectors. The device adopted by California, which has applied since 2009, plans to reduce emissions of gaseous pollutants from 22% on average by 2012 and 30% by 2016. In addition, the principle markets of emission permits is to grant industrial “polluters” free, fixed price or auction emissions allowances to CO 2 , that they can then exchange. Each issuer of CO 2 must then verify that it has as many emission permits that it will issue. Otherwise, he is forced either to reduce its emissions or buying permits. Conversely, if its efforts to control emissions allow it to have a surplus of permits it can sell. Such processes have been made to reduce acid rain in the U.S. and have been successful (program “ Acid rain “). The procurement system of emission permits is part of the device of the Kyoto Protocol was not ratified by the United States in July 2006 169 . In 2004 , Republican Senator John McCain and Democrat Joseph Lieberman file a bill to limit releases to the atmosphere supported by large companies Alcoa, DuPont and American Electric Power , it is not yet adopted . The U.S. fund with China, Japan, Russia and the EU, the ITER ( International Thermonuclear Experimental Reactor ) research project on nuclear fusion, leading to Cadarache (Southern France). However, the net energy production by auctions online nuclear fusion is hot to the state of distant hope: the most optimistic forecasts of project proponents speak of decades. On July 8, 2008, George Bush signs a text committing the U.S. to halve emissions of greenhouse gases by 2050 , in Toyako ( Japan ), as part of a meeting of the G8 . In early December 2009, the agency environmental protection in the United States (EPA) issue a statement declaring that the emissions of greenhouse gases considered responsible for global warming is a threat to public health 170 . Fight against climate change in China China to fight against global warming, investing in more advanced fields: the wind . Between 2004 and 2008, the number of wind turbines installed in China is doubling every year 171 . In 2009, she became the third largest producer of wind power, and should become the first in 2012 to 172 ; Energy Photovoltaics . China is the world’s largest producer of photovoltaics 173 ; capture of CO 2 in coal fired power plants. China now sells its technology to U.S. 173 ; promoting state-subsidized Chinese light bulbs of electricity 174 . Newly industrialized countries against the United States [ change ]
The top ten issuers of CO 2 in the world in 2006. A point of debate is to what extent the newly industrialized countries such as the India and China should restrict their emissions of CO 2 . The CO 2 from China surpassed those of the United States in 2007, 175 , 176 while it only produces 5.4 times more wealth than the European Union or the United States 177 , and n ‘ should, in theory, reach this level until around 2020. In 2007, China is the largest producer and consumer of coal , its primary source of energy, which is extremely polluting. In addition, the increased standard of living increases the demand for “energy” such as automobiles and air conditioners. China responded that it had fewer obligations to reduce emissions of CO 2 per capita accounting for one sixth that of U.S. 178 . India, also one of the biggest polluters of the planet, has made the same assertions, emissions CO 2 per capita for almost twenty times lower than U.S. 179 . However, the United States countered that they should bear the cost of reductions in CO 2 , China should do the same 180 . Individual measures to fight against global warming
Ranking the top 15 emitters of CO 2 in the world in 2006, per capita. Humanity is currently rejecting 6 Gt (gigatons = billion tons) of carbon equivalent per year into the atmosphere, or about one tonne per capita. It is estimated that the oceans absorb 3 Gt and should therefore reduce greenhouse gas emissions by half to stop enriching the atmosphere, representing an average emission of 500 kg carbon equivalent per capita . French in each emits about two tons, four times more than it should be 181 . Apart from collective action, personalities have outlined the everyday actions to implement, starting today, to limit global warming as Jean-Marc Jancovici 182 and Al Gore 183 . Some measures are energy savings, especially fossil fuels: avoid taking the plane 184 . A mile long-haul plane emits 60 grams of carbon equivalent per person 185 , an intercontinental travel accounts for almost 500 kg of carbon equivalent. A fortiori , for short-haul trips ( 100 g of carbon equivalent per kilometer and person), prefer the train; use the least possible motor vehicles (preferring the bicycle or public transportation whenever possible). A car emits between 100 and 250 g equivalent CO 2 per km, between 30 and 70 g of carbon equivalent. 20 000 km per year account for between 600 and 1 400 kg of carbon equivalent. If a car is necessary, choose the model the least polluting and most efficient way possible (for example, some manufacturers have 
announced the vehicles that consume less than 1.5 liters for 100 km 186 , 187 ); achieve optimal insulation of buildings, at best by using the bioclimatic architecture that minimizes the need for heating ( 15 kWh ⋅ m -2 per year, the old houses being 450 kWh ⋅ m -2 per year) eliminates the need for active cooling, while improving the comfort of life. Sustainable development policies Main article: Sustainable Development . Solving the problem of global warming involves taking into consideration not only the parameters that are directly involved in global warming, namely the emission of greenhouse gases , but also all the environmental information , as well as social and economic indicators according to the principles developed at the Earth Summit in Rio de Janeiro in 1992 , which identified three pillars in sustainable development : environmental , social, and economic. States’ response is therefore now through national strategies for sustainable development , these communities through of Agenda 21 , and those companies through the corporate social responsibility . The development falls within cross-cutting programs in organizations 188 . Each area is expected to contribute to the effort. The computer , for example, far from being virtual or immaterial , appears as a sector emitter of greenhouse gases note 8 . According to Jean-Marc Jancovici , the dematerialization has not brought up this solution to the problem of global warming, because we found a correlation between the flow of information and physical flows 189 . It is therefore necessary that the computer industry sets goals for sustainable development. This has been done with the creation in 2007, Google and the WWF in the Climate Savers Computing Initiative , a joint initiative with several computer manufacturers to halve energy consumption of computers by 2010. Controversy on global warming
Main article: Controversies on global warming . The existence of global warming is almost consensus within the scientific community and more climatologists 190 , 191 . This does not, however, controversy on: the operation of the IPCC: need to check carefully the data generated, and take into account the different views; the validity of the conclusions of the IPCC: importance of global warming, likely attributed to the scenarios, the importance of anthropogenic causes, etc.. ; the consequences of global (accusations of over-estimation of the negative and positive effects of concealment); policies to be implemented to counter this climate phenomenon (arbitration priority among the other pro