With everyone being so busy all the time, I thought I would give a quick snapshot of the key findings of the Intergovernmental Panel on Climate Change (IPCC) final report that was released on Saturday after a week of negotiations by government officials from around theย world.
This is the final report of the IPCC and probably the most valuable, as it will be used as a key reference documents at the United Nations Framework Convention on Climate Change (UNFCCC) meeting that will be held in Bali, Indonesia at the beginning of December. At the meeting in Bali government leaders will begin negotiations on a successor to the Kyotoย Protocol.
If you want to read the entire document, here’s the link to the PDF version. If you only have 5 minutes or so, here’s the key findings pulled directly from theย report:
โWarming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.Eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperature (sinceย 1850).โ
โRising sea level is consistent with warming (Figure SPM.1). Global average sea level has risen since 1961 at an average rate of 1.8 [1.3 to 2.3]mm/yr and since 1993 at 3.1 [2.4 to 3.8]mm/yr, with contributions from thermal expansion, melting glaciers and ice caps, and the polar ice sheets. Whether the faster rate for 1993 to 2003 reflects decadal variation or an increase in the longer-term trend isย unclear.โ
โObserved decreases in snow and ice extent are also consistent with warming (Figure SPM.1). Satellite data since 1978 show that annual average Arctic sea ice extent has shrunk by 2.7 [2.1 to 3.3]% per decade, with larger decreases in summer of 7.4 [5.0 to 9.8]% per decade. Mountain glaciers and snow cover on average have declined in bothย hemispheres.โ
โFrom 1900 to 2005, precipitation increased significantly in eastern parts of North and South America, northern Europe and northern and central Asia but declined in the Sahel, the Mediterranean, southern Africa and parts of southern Asia. Globally, the area affected by drought has likely2 increased since theย 1970s.โ
โIt is very likely that over the past 50 years: cold days, cold nights and frosts have become less frequent over most land areas, and hot days and hot nights have become more frequent. It is likely that: heat waves have become more frequent over most landย areasโฆโ
โAverage Northern Hemisphere temperatures during the second half of the 20th century were very likely higher than during any other 50-year period in the last 500 years and likely the highest in at least the past 1300ย years.โ
โObservational evidence4 from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperatureย increases.โ
โOf the more than 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 toย warmingโฆโ
โGlobal GHG emissions due to human activities have grown since pre-industrial times, with an increase of 70% between 1970 andย 2004.โ
โCarbon dioxide (CO2) is the most important anthropogenic GHG. Its annual emissions grew by about 80% between 1970 and 2004. The long-term trend of declining CO2 emissions per unit of energy supplied reversed afterย 2000.โ
โGlobal atmospheric concentrations of CO2, methane (CH4) and nitrous oxide (N2O) have increased
markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands ofย years.โ
โThere is very high confidence that the net effect of human activities since 1750 has been one ofย warming.โ
โMost of the observed increase in globally-averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic [human-caused] GHGย concentrations.โ
โDuring the past 50 years, the sum of solar and volcanic forcings would likely have producedย cooling.โ
โHuman influences have: very likely contributed to sea level rise during the latter half of the 20th century; likely contributed to changes in wind patterns, affecting extra-tropical storm tracks and temperature patterns; and, likely increased temperatures of extreme hot nights, cold nights and coldย days.โ
โContinued GHG emissions at or above current rates would cause further warming and induce many
changes in the global climate system during the 21st century that would very likely be larger than those observed during the 20thย century.โ
โThe uptake of anthropogenic carbon since 1750 has led to the ocean becoming more acidic with an average decrease in pH of 0.1 units. Increasing atmospheric CO2 concentrations lead to furtherย acidification.โ
โAnthropogenic warming and sea level rise would continue for centuries due to the timescales associated with climate processes and feedbacks, even if GHG concentrations were to beย stabilised.โ
โAnthropogenic warming could lead to some impacts that are abrupt or irreversible, depending upon the rate and magnitude of the climate change. โ
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