The latest review of climate science from the Intergovernmental Panel on Climate Change (IPCC), though not finalized, is making the rounds. The prevailing headline is that the panel is more certain than ever that most of the warming observed in recent decades is human-caused. It’s level of certainty has increased from at least 90 percent in 2007 to at least 95 percent in the new report.
Officials from the IPCC stress that the leaked draft is not its final product. A government review is ongoing, so some of the conclusions may be altered. But here are some of the more interesting preliminary findings….
1) The recent rate of increase in carbon dioxide, methane and nitrous oxide in the atmosphere is unprecedented in the last 22,000 years.
2) Glaciers worldwide shrunk 22 percent faster from 1993-2009 compared to the longer period from 1971-2009.
3) The Greenland Ice Sheet lost mass about 6 times faster between 2002-2011 compared to the period from 1992-2001.
4) The Antarctic Ice Sheet lost mass nearly 5 times faster between 2002-2011 compared to the period from 1992-2001.
5) Sea level rise from 1901 to 2010 occurred at a rate of 1.7 millimeters per year and increased to 3.2 millimeters per year between 1993 and 2010.
6) Arctic sea ice extent decreased at a rate of 3.5 to 4.1 percent per decade from 1979-2012.
7) The 30 years from 1983-2012 was very likely the warmest 30-year period of the last 800 years.
8) The global average temperature is projected to warm by (an average of) 2 to 7 degrees F by 2100, depending on future greenhouse gas emissions and climate sensitivity.
9) The global average sea level is projected to rise by (an average of) 16 to 24 inches by 2100, depending on future greenhouse gas emissions and climate sensitivity.
10) It is very likely that more than 20 percent of carbon dioxide released into the atmosphere will remain there over 20,000 years after emissions stop.
This is just a sprinkling of some of the findings – focused on observed and projected changes in temperature, ice sheets and sea level. When the report is finalized, I’ll provide a closer look…