1.1 Global Warming Estimated Global Temperature and Growth Rate since 1850 14.6 Estimated global mean temperature C 14.4 14.2 14.0 13.8 13.6 Period Years 25 50 100 150 Annual mean Smoothed series Growth C per decade 0.177 ± 0.052 0.128 ± 0.026 0.074 ± 0.018 0.045 ± 0.012 5-95% decadal error bars 13.4 13.2 Source: IPCC, 1 st working group, 2007 > The global average temperature has increased by 0.74 C over the last century. Over the last 25 years, the rate of temperature growth has been the highest during the entire century. > In metropolitan France, the average temperature has increased by 0.7 C over the century in the north-eastern part of the country. The increase is even larger in the southwestern part where it reached 1.1 C. 2.0 Mean temperature evolution in continental France since 1900 compared with the reference period average 1961-1990 1.5 1.0 0.5 C 0.0 0.5 1.0 1.5 Temperature spread Decadal average Source: Météo-France, 2011 > 2011 has been the warmest year on record in metropolitan France since 1900. At the global scale, the last seventeen years (1995-2011) include sixteen of the seventeen warmest years since 1900. 2
Consequences of Climate Change 1.2 Continuous Increase in Sea Level since the 1900s 200 Global average sea level 150 100 mm 50 0 50 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Red bars represent estimates and uncertainty from Church et al. (2004). Blue points represent estimates from Jevrejeva et al. (2006). Extreme Weather Events Source: Les Climats du XXI e siècle, n 3, 2012 > The global average sea level increased by 1.7 ± 0.2 mm/year between 1901 and 2009. The rise in sea level is further increasing in speed: it reached 3.2 ± 0.4 mm/year over the 1993-2011 period. > A weather event is classified as extreme when it substantially exceeds the baselines. > Climate change modifies the frequency, intensity, scale, duration and time of occurrence of extreme events. It can bring these events (tornadoes, hurricanes, as well as heat waves or abnormally heavy rainfalls) to unprecedented levels. 30 Abnormally cold and warm days in the world Difference from 1951-1990 average ( C) 20 10 0 10 1950 1960 1970 1980 1990 2000 Abnormally cold days Abnormally warm days The baseline used is the mean of the indicator considered over the period 1951-1990. The orange curves represent the mobile averages per decade. All regions worldwide are not included due to insufficient data. Source: IPCC, 1 st working group, 2007 3
1.2 Consequences of Climate Change Annual Evolution of Seeding Dates Evolution of corn seeding dates in four experimental units Mirecourt Colmar Le Pin Auzeville 8-Jun 29-May 19-May 9-May Date 29-Apr 19-Apr 9-Apr 30-Mar 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 Year Source: INRA > Observations show that the seeding dates for corn are increasingly earlier. Shortening physiological cycles also leads to earlier maturity and harvests. Melting Ice Compared pictures showing the evolution of the glacier of Ossoue (France) Source: Moraine (Pyrenean association of glaciology), 2011 > Since 1911, the diameter of the glacier of Ossoue has been shortened by 540 meters. In 100 years, its area has decreased from about 110 to 45 hectares, namely an area loss of 59%. 4
Forecast of the Future Climate 1.3 Change in Consecutive Dry Days (CDD) Change in consecutive dry days 2081-2100 (CDD precipitations under 1 mm) The increased drought is represented by the yellow to red colors, drought mitigation by the green to blue colors. Source: IPCC, SREX, 2012 > Climate extremes will have a significant impact on industries that are closely related to climate, such as access to water resources, agriculture and food production, forestry, health and tourism. Consequences for France Number of additionnal abnormally warm days in the future (IPCC A2 scenario) Reference 1970 Mean term 2055 Long term 2085 Source: Drias, 2012 5
1.3 Forecast of the Future Climate Projections of Sea Level Rise In cm Hypothesis 2030 2050 2100 Optimistic 10 17 40 Pessimistic 14 25 60 Extreme 22 41 100 Projections of sea level rise relative to the values of the late twentieth century, expressed in cm, depending on the assumptions surrounding climate change impacts. Source: Onerc, 2010 > The main drivers of growth in sea level are the thermal expansion and the melting of terrestrial ice (glaciers, polar ice caps,...). > The increase in sea level is likely to cause heavy migration of populations, since 80% of the humanity lives in coastal areas. Extension of Forest Fires Risk Areas Sensitivity to summer forest fires of forest massifs (> 100 ha) Baseline 1989-2008 2040 1 (Average Index 1.6) 2 (1,6 < Average Index < 2.5) 3 (Average Index 2.5) Source: Interministerial report, July 2010 > By 2040, areas sensitive to forest fires will extend in altitude and to the north. Moderately sensitive areas like the forest of Aquitaine will become very sensitive. Areas with historically little or no risk will be at moderate risk, such as the massifs of Sologne and the forest of Fontainebleau. 6
The Greenhouse Effect 1.4 The Atmosphere s Role on the Greenhouse Effect Energy flows, with or without greenhouse gases (GHGs) 342 107 Atmosphere without GHGs 342 107 235 Atmosphere with GHGs In W / m 2 235 235 19 C 67 168 +14 C > The sun supplies energy through its rays to the Earth which, in return, radiates an equal quantity of energy in the form of infrared radiation (IR). In the absence of greenhouse gases (GHGs), the temperature of the Earth would be -19 C. > With GHGs in the atmosphere, a portion of the IR is reflected back towards the surface of the Earth. The Earth s temperature increases until the energy radiated is equal to that absorbed. The presence of GHGs leads to an increase in surface temperature, which then reaches +14 C. Increased GHG anthropogenic emissions imbalance the system and the equilibrium temperature increases. The increased forcing is estimated at + 2.81 W/m 2 in 2010 (source: National Oceanic and Atmospheric Administration). The Atmosphere and Greenhouse Gases Source: adapted from IPCC, 1 st working group, 2007 Composition of the dry atmosphere Share of the main greenhouse gases in the reflection of radiation towards the surface In % of volume excluding H2O In % Others 1.0 Oxygen (O2) 20.9 Nitrogen (N2) 78.1 Methane (CH4) and Nitrous oxide (N2O) 6 Ozone (O3) 8 Carbon dioxide (CO2) 26 Water vapor (H2O) 60 Source: IPCC, 1 st working group, 2001 NB: proportions in the absence of clouds. Source: Kiehl & Trenberth 1996 > GHGs other than water vapor make up less than 0.1 % of the atmosphere. Water vapor, which fluctuates from 0.4 % to 4 % in volume is the main greenhouse gas. It is natural and human activities have little impact on its fluctuations. > However, during the industrial era, the development of human activities that emit GHGs, called anthropogenic, magnified the natural greenhouse effect, causing an increase in atmospheric temperature. 7
1.5 Humans and the Greenhouse Effect Characteristics of GHGs Influenced by Human Activity CO2 CH4 N2O HFCs PFCs SF6 NF3 Atmospheric concentration 2010 389 ppm 1,808 ppb 323 ppb 96 ppt 82 ppt 7.0 ppt < 1 ppt Lifespan in the atmosphere Between 2 years and thousand of years 12 years 114 years Between 0.3 and 270 years Between 1,000 and 50,000 years 3,200 years 740 years Global warming potential (total over 100 years) 1 25 298 [12; 14,800] [7,300; 12,200] 22,800 17,200 Anthropogenic sources Burning of fossil fuels and tropical deforestation Landfills, agriculture, livestock and industrial processes Agriculture, industrial processes, use of fertilizer Aerosols, refrigeration, aluminium smelting Manufacture of electronic components Change in radiative forcing due to anthropogenic emissions since 1750 (W / m 2 ) +1.66 +0.48 +0.16 +0.017 Notes: Ozone and water vapor omitted due to the complexity of their lifecycles. ppm = part per million, ppb = part per billion, ppt = part per trillion. Source: IPCC, 1 st working group, 2007 and ESRL/NOAA, 2012 8 > The Global Warming Potential (GWP) is the ratio between the energy reflected towards the surface over 100 years by 1 kg of the gas and that which would be reflected by 1 kg of CO2. The GWP depends on the concentration and lifespan of each gas. E.g.: 1 kg of CH4 and 25 kg of CO2 would heat the atmosphere equally over the century following their emissions. > Radiative forcing (in W/m 2 ) quantifies, in relation to a year of reference (here 1750), the changes in radiation, or the energy reflected by the atmosphere back towards the surface due to GHGs. A positive value indicates a positive contribution to warming and vice versa. > Although CO2 has the smallest global warming potential of all GHGs, it has contributed the most to global warming since 1750. > Some human activities also contribute to reducing radiative forcing, most notably through the emissions of aerosols. However this negative radiative forcing, estimated at 1.20 W/m 2 since 1750, does not compensate for the positive radiative forcing of the six anthropogenic GHGs which reached +2.81 W/m 2 in 2010, increasing by 1.2% compared to 2009.
Carbon Stocks and CO2 Flows 1.6 The Simplified CO2 Cycle Volcanism < 0.4 Cement Production Land Use Change and Soil and Fossil Fuel Sequestration Combustion 3.7 1.5 23.5 Atmosphere [2,189 + 605] 1.5 8.1 Geological Reservoirs [13,567 895] Biosphere [8,433 143] Ocean [139,333 + 433] Sedimentation 0.7 This figure shows (i) as arrows, the carbon fluxes between reservoirs over the 1990-1999 period in billions of tonnes of CO2 equivalent per year; (ii) between square brackets the size of the reservoirs in billions of tonnes of CO2 equivalent and their variation over the 1750-2004 period. Pre-industrial reservoirs and flows are in black. Reservoirs variations and flows induced by human activities since 1750 are in red. Source: adapted from IPCC, 1 st working group, 2007 > Four large reservoirs or stocks allow the storage of carbon in different forms: - Atmosphere: gaseous CO2; - Biosphere: organic material and living things including forests; - Ocean: calcium, dissolved CO2; - Subsoil: rocks, sediments, fossil fuels. > Flows of carbon between these reservoirs constitute the natural carbon cycle which is disrupted by human activities which change the size of the flows or create new ones. E.g.: the burning of fossil fuels (coal, petroleum ). > Of the 1,038 GtCO2 liberated by human activities from the biosphere and the lithosphere, the atmosphere has absorbed 605 Gt and the oceans 433 Gt. The atmosphere is the reservoir which is the most affected by human activities: the quantity of carbon absorbed has increased by 30% compared to the pre-industrial era. 9
1.7 Increase in Atmospheric GHG Levels Imbalance between Emissions and Storage Capacity 30 Annual changes in CO2 by source, reservoir and their associated uncertainties 25 Uncertainty 20 15 10 Gt CO2 / year 5 0 5 10 Cement production and fossil fuel combustion 26.4 Land-use change 5.9 Terrestrial reservoir 9.5 Oceanic reservoir 8.1 Resultant flows to the atmosphere 15.0 15 20 Emissions data from the burning of fossil fuels, the production of cement, the oceanic reservoir and the growth of the atmospheric reservoir are for the period 2000-2005. The terrestrial flows are for the 1990s. Source: IPCC, 1 st working group, 2007 > Since the increase in industrial activities, terrestrial and oceanic reservoirs have absorbed half of the human-related emissions. The atmosphere has absorbed the other half, which has led to increased concentration of greenhouse gases. > Forests are the largest terrestrial carbon reservoir. They store approximately 9.5 GtCO2e net emissions per year, equivalent to 30% of global GHG emissions. > In France, carbon flow in forest biomass is estimated at 17.1 million tonnes of carbon per year, or 17% of national emissions of fossil carbon (INRA, 2006). > Deforestation leads to GHG emissions through the burning and decomposition of organic matter. These emissions represent approximately 11% of yearly anthropogenic GHG emissions (source: Van der Werf et al. 2009, Nature Geoscience). 10
GHG Concentrations and Temperatures 1.8 Historic Evolution of GHG Concentrations CO2 (ppm), N2O (ppb) 400 350 300 Carbon dioxide (CO2) Methane (CH4) Nitrous oxide (N2O) {CH4 1,774 ppb +148%} {CO2 379 ppm +35%} {N2O 270 ppb +18%} Beginning of the industrial era 1,800 1,600 1,400 1,200 1,000 CH4 (ppb) 800 250 1 500 1000 1500 2000 The figures in brackets indicate the atmospheric concentration of GHGs in 2005 and their growth rate between 1750 and 2005. > The stable nature of concentrations before the industrial era shifted radically in 1750, exhibiting a strong increase in levels due to the intensification of human activities emitting large quantities of GHGs. In late 2011, atmospheric CO2 concentration reached 391.4 ppm (source: NOAA, 2012). This is 30% higher than the maximum observed over the past 400,000 years of weather data. Temperature and CO2 concentration in the atmosphere over the past 400,000 years Difference from current temperaure ( C) 4 2 0-2 -4-6 -8-10 -12-14 -16-18 400,000 350,000 300,000 250,000 200,000 Years ago 150,000 These results were obtained from the analysis of ice cores sampled at Vostok (Antarctica). Source: World Data Center for Paleoclimatology, Boulder & NOAA Paleoclimatology Program > The variations in global temperature and CO2 concentration have a very clear correlation. If the causes are still poorly understood, it is believed that disrupt one of these two parameters leads to disrupt the other. 600 Source: IPCC, 1 st working group, 2007 100,000 50,000 450 400 350 300 250 200 150 Today Concentration of CO2 (ppm) 11