Monday, March 31, 2014

New IPCC Report

On Sunday, the Intergovernmental Panel on Climate Change (IPCC) released Part 2 of their Assessment Report. (Or you can go directly to the technical summary.) I have not had a chance to read it all yet, but there are already some resources out there already that have overviews of the findings at Future Tense, Skeptical Science, Bad Astronomy and in the Guardian.

Part 1 of the report, which demonstrated that climate change is real and happening, and that human activities are the cause, was released in September, 2013.

Part 2 focuses on the impacts of climate change, and what might be done to minimize the effects. It complies and evaluates the results from articles published in scientific journals in the field, and synthesizing the consensus position of the scientific community on the issues. Basically - climate change is here, now and we are already seeing the affects - some key highlights ...

  • Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased
  • Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years (medium confidence).
Map of the observed surface temperature change from 1901 to 2012 derived from temperature trends determined by linear regression from one dataset. Trends have been calculated where data availability permits a robust estimate (i.e., only for grid boxes with greater than 70% complete records and more than 20% data availability in the first and last 10% of the time period). Other areas are white. Grid boxes where the trend is significant at the 10% level are indicated by a + sign
  • Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971.
  • Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence)

Extent of Arctic July-August-September (summer) average sea ice
  • 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). Over the period 1901 to 2010, global mean sea level rose by 0.19 [0.17 to 0.21] m

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