IPCC WGI third assessment report: summary for policymakers

IPCC WGI third assessment report: summary for policymakers

Assessing the prospects for climate change: predictions and analyses

The Third Assessment Report of Working Group I of the Intergovernmental Panel on Climate Change (IPCC) builds upon past assessments and incorporates new results from the past five years of research on climate change. Many hundreds of scientists from many countries participated in its preparation and review.

This summary for policymakers, which was approved by IPCC member governments in Shanghai in January 2001, describes the current state of understanding of the climate system and provides estimates of its projected future evolution and their uncertainties.

Conclusions

  • An increasing body of observations gives a collective picture of a warming world and other changes in the climate system
  • Emissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to affect the climate
  • Confidence in the ability of models to project future climate has increased
  • There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities
  • Human influences will continue to change atmospheric composition throughout the 21st century
  • Global average temperature and sea level are projected to rise under all IPCC SRES scenarios
  • Anthropogenic climate change will persist for many centuries
  • Further action is required to address remaining gaps in information and understanding

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