The Naval Postgraduate School & The U.S. Department of Homeland Security

IPCC Releases Newest Report on Climate Change

The IPCC [Intergovernmental Panel on Climate Change] revealed today the climate change findings of Working Group I, out of Stockholm, Sweden. These findings constitute the first part of the IPCC's Fifth Assessment Report (AR5) on climate change, titled "Climate Change 2013: The Physical Science Basis." This report outlines the scientific conclusions and contributions of the Group to the AR5.

"The Working Group I contribution to the IPCC's Fifth Assessment Report (AR5) considers new evidence of climate change based on many independent scientific analyses from observations of the climate system, paleoclimate archives, theoretical studies of climate processes and simulations using climate models. It builds upon the Working Group I contribution to the IPCC’s Fourth Assessment Report (AR4), and incorporates subsequent new findings of research."

A few of the Group's main conclusions, from the "Summary for Policymakers", are as follows:

  • "Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes [...]. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century."
  • "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."
  • "Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system."
  • "It is very likely that the Arctic sea ice cover will continue to shrink and thin and that Northern Hemisphere spring snow cover will decrease during the 21st century as global mean surface temperature rises. Global glacier volume will further decrease."

This report is the first of four reports to be released on climate change 2013. Working Group II will publish its findings on March 2014, Working Group III will release its report in April 2014, and a full synthesis report will be published in October 2014. For the full schedule, including the official release of Working Group I's report, visit the IPCC's AR5 webpage.