Schematic framework of anthropogenic climate change drivers, impacts and responses to climate change, and their linkages (IPCC, 2007).

Warming of the climate system is unequivocal, as is evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level (IPCC, 2007).

Arctic sea ice extent anomalies (1970-2002).

Of the 29,000 observational data series from 75 studies, that show significant change in many physical and biological systems, more than 89% are consistent with the direction of change expected as a response to warming (IPCC, 2007). Changes in physical and biological systems and surface temperature 1970-2004 (IPCC, 2007).

(a) Global annual emissions of anthropogenic GHGs (greenhouse gases) from 1970 to 2004. (b) Share of different anthropogenic GHGs in total emissions in 2004 in terms of CO2-eq. (c) Share of different sectors in total anthropogenic GHG emissions in 2004 in terms of CO2-eq. (forestry includes deforestation) (IPCC, 2007).

(a) Distribution of regional per capita GHG emissions according to the population of different country groupings in 2004. (b) Distribution of regional GHG emissions per US$ over the GDP of different country groupings in 2004. The percentages in the bars in both panels indicate a region’s share in global GHG emissions. (IPCC, 2007).

Relative importance of atmospheric gases and particulate matter on global warming versus cooling. Note that methane gas has a greater greenhouse effect than CO2 gas, but its anthropogenic productioin and overall atmospheric level is lower.

Anthropogenic concentrations of CO2, CH4 and N2O) over the last 10,000 years (large panels) and since 1750 (inset panels). Measurements are shown from ice cores (symbols with different colors for different studies) and atmospheric samples (red lines). The corresponding radiative forcings relative to 1750 are shown on the right hand axes of the large panel (IPCC, 2007). The atmospheric concentrations of CO2 and CH4 in 2005 exceed by far the natural range over the past 650,000 years.

Global average radiative forcing (RF) in 2005 with respect to 1750 for CO2, CH4 and N2O and other important agents and mechanisms (IPCC, 2007).

Comparison of observed continental- and global-scale changes in surface temperature with results simulated by climate models using either natural or both natural and anthropogenic forcings.

Scenarios for GHG emissions from 2000 to 2100 in absence of additional climate policies (IPCC, 2007). SRES - (Special Report on Emission Scenarios, 2000).

Boundary conditions used to produce general circulation models of past and future climate change.

CLIMAP reconstruction of SST (°C) during the Last Glacial Maximum, ~18000 years ago.

Atmosphere-Ocean General Circulation Model projections of surface warming (2020-2029 and 2090-2099). IPCC, 2007.

Relative changes in precipitation (in percent) for the period 2090-2099, relative to 1980-1999. Values are multi-model averages based on the SRES A1B scenario for December to February (left) and June to August (right). White areas are where less than 66% of the models agree in the sign of the change and stippled areas are where more than 90% of the models agree in the sign of the change (IPCC, 2007).

CO2 emissions and equilibrium temperature increases (above pre-industrial for a range of stabilization levels.