On September 26, 2013 the Intergovernmental Panel on Climate Change (IPCC) released the first of its three Fifth Assessment reports on the status of climate change.  The Working Group I report (WGI) took over three years to complete and is one of the most significant reports on climate change in the last decade. The report is based on the contributions of hundreds of expert scientists, an exhaustive review of the peer-reviewed scientific literature, and a rigorous review process lasting upwards to seven years.  Some of the critical statistics supporting the credibility of the report are as follows:*

  • 209 lead authors and 50 review editors from 39 countries
  • Over 600 contributing authors from 32 countries
  • Over 2 million gigabytes of numerical data from climate model simulations
  • Over 9,200 scientific publications cited
  • 1,089 expert reviewers from 55 countries and 38 governments

The report, Climate Change 2013: The Physical Science Basis, covers the direct and proxy observations on changes to the climate system and builds on the 2007 Fourth Assessment Report to “understand past, document current, and project future climate change” and its effects.  Although many climate change skeptics cite that the rate of surface temperature warming has slowed over the last decade, the IPCC has actually strengthened its certainty that human activities are the core cause of unprecedented climate change over the past half century, raising their confidence to “extremely likely,” compared to “very likely” in 2007 and “likely” in 2001. Despite evidence of a brief slowing of in surface temperature warming, the consensus on the macro trend and causes continues to solidify, including the trend of increases in extreme weather events and climate impacts that are taking drastic tolls on people and economies.


*Adapted from 4CP Newsletter IPCC Supplement, October 31, 2013