Environment Counts | IPCC AR5 Climate Change 2014 Synthesis Report approved 1 November 2014 :
The AR5 Synthesis Report, which is based on the reports of the three Working Groups of the Intergovernmental Panel on Climate Change (IPCC), provides an integrated view of climate change in the IPCCâ€™s Fifth Assessment Report (AR5). It has now been accepted by all member countries.
Some of the most important conclusions based on field observations are;
- The globally averaged combined land and ocean surface temperature data shows a warming of 0.85 (0.65 to 1.06) Â°C over the period 1880 to 2012.
- Ocean warming accounts for more than 90% of the energy accumulated between 1971 and 2010 (high confidence), with only about 1% stored in the atmosphere.
- Since the beginning of the industrial era, the acidity of the oceans has increased by 26%, corresponding to an decrease in the pH of surface waters of 0.1 (high confidence).
- Between 1992 to 2011, the Greenland and Antarctic ice sheets have been losing mass (high confidence).
- Glaciers have continued to shrink almost worldwide (high confidence).
- Permafrost temperatures have increased in most regions since the early 1980s (high confidence).
- Arctic sea-ice extent has decreased in every season and in every successive decade since 1979 (high confidence).
- Over the period 1901 to 2010, global mean sea level rose by 0.19 (0.17 to 0.21) m. The rate of sea-level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence).
- Anthropogenic greenhouse gas emissions have increased since the pre-industrial era. Atmospheric concentrations of carbon dioxide, methane and nitrous oxide are unprecedented in at least the last 800,000 years.
- The largest contribution to “Other anthropogenic forcing” is man-made aerosols. A major conclusion of AR5 is that aerosols are the dominant contributor to uncertainty in the net effect of anthropogenic sources during the Industrial Era. However, there is a high confidence that aerosols have offset a substantial portion of greenhouse gas climate warming.
- Between 1750 and 2011, cumulative anthropogenic CO2 emissions to the atmosphere were 2040 Â± 310 GtCO2. About 40% of these emissions have remained in the atmosphere (880 Â± 35 GtCO2). The ocean has absorbed about 30% of the emitted anthropogenic CO2. The rest was removed from the atmosphere and stored on land (in plants and soils).
- About half of the anthropogenic CO2 emissions between 1750 and 2011 have occurred in the last 40 years (high confidence).
In conclusion the report states that;
- Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history.
- Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia.