IPCC Fifth Assessment Report

What is the IPCC and why is it important?

The Intergovernmental Panel on Climate Change (IPCC) is the leading international body for the assessment of climate change. It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide the world with a clear scientific review of the current state of knowledge on climate change.

Thousands of scientists from all over the world volunteer and are selected to review and assess the latest relevant scientific, technical and socio-economic data to understand climate change, its potential impacts, and options for adaptation and mitigation. The IPCC aims to reflect a range of views and expertise in order to publish comprehensive and objective assessments.

The IPCC does not conduct independent research, rather it convenes climate experts from around the world every five to seven years to synthesize the latest climate research findings in peer-reviewed and published scientific/technical literature. The IPCC issued comprehensive assessments in 1990, 1995, 2001, and 2007.

IPCC reports are never policy prescriptive but the conclusions are relevant to nations, states, and businesses interested in enacting policies to limit future warming and reduce the costs of climate change.

What is the Fifth Assessment report?

The Fifth Assessment Report (AR5) is the latest in a series of reports from the IPCC assessing scientific, technical, and socio-economic information regarding climate change. It will be released in three installments over the course of 2013 and 2014, and an additional synthesis report will be published in October 2014.

More than 830 scientists are involved in writing the reports and hundreds more will review and edit the draft reports.

AR5 will comprise three sections, or working groups:

  • Working Group I provides a comprehensive assessment of the physical science basis of climate change: Released Sept. 27, 2013
  • Working Group II assesses the scientific, technical, environmental, economic and social aspects of vulnerability to climate change as well as consequences for ecological systems, socio-economic sectors and human health: Release date March 31, 2014
  • Working Group III assesses all relevant options for mitigating climate change through limiting or preventing greenhouse gas emissions and taking actions to remove them from the atmosphere: Release date April 11, 2014

The syntheses report is scheduled to be released Oct. 31, 2014

Each working group report has a Summary for Policymakers that distills the key points from the hundreds of pages found in the respective full report. The Summary for Policymakers tend to be of most interest to the media and non-scientists.

What are the key points in the IPCC Working Group I Summary for Policymakers?

The Summary for Policymakers (SPM) includes the key conclusions from the longer report in a format suitable for a broader audience. The SPM will include observations of changes in the atmosphere, ocean, and cryosphere, including changes in sea level. It will also discuss our confidence in attributing climate change to human activities. The SPM will also include projections of global and regional climate change for the 21st century, including projected changes in the water cycle, extreme weather, sea level, sea ice, and the carbon cycle.

It answers such questions as:

  • What is the state of the science in understanding and attributing climate changes?
  • What are the primary drivers of climate change?
  • How do recent changes compare to paleoclimatic records?
  • In what ways is climate change is already occurring around the globe and how fast are these systems changing?
  • What are models projecting for the 21st century climate and how accurate are they?
  • Which types of climate changes might be irreversible?

What are the key points in the IPCC Working Group II Summary for Policymakers?

The IPCC Working Group II Summary for Policymakers (WGII SPM) includes important statements and conclusions from the WGII report and is aimed at a broader audience. The WGII SPM is divided into three sections: 1. Observed Impacts, Vulnerability, and Adaptation in a Complex and Changing World; 2. Future Risks and Opportunities for Adaptation; and 3. Managing Future Risks and Building Resilience.

The WGII SPM answers such questions as:

  • What climate-related impacts are already being observed today?
  • What are the key future risks in areas such as water resources, coastal and marine systems, food security, human health, security, and economic growth?
  • Which groups of people are the most vulnerable?
  • What kind of adaptation actions have already been undertaken and which actions could be taken to reduce these future risks?
  • How can adaptation decisions be made when the future is uncertain?
  • What constitutes effective adaptation action and climate-resilient development?

 

Additional resources:

IPCC AR5 Highlights from Working Group I

The IPCC's growing certainty of human involvement in global warming

IPCC homepage

IPCC page on AR5 activities

IPCC WGI homepage

IPCC WGII homepage

National Center for Atmospheric Research

C2ES Summaries of Fourth Assessment Report