IPCC 5th Assessment Report - AR5
The Intergovernmental Panel on Climate Change (IPCC) is the international body for assessing the science related to climate change. It was set up in 1988 by the World Meteorological Organization and the United Nations Environment Programme to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation. The IPCC writing cycle for the development covers 4 years.
The five IPCC assessments reports have influenced global action on an unprecedented scale. The 5th Assessment Report (AR5) currently under approval, is undoubtedly the best and most comprehensive report ever produced by the IPCC. It was produced by 831 lead authors, selected from around 3,000 CVs submitted by all countries.
Key messages
The Key Messages of the Working Group I may be summarized in the 3 following points:
- Warming of the climate system is unequivocal
- Human influence on the climate system is clear;
- Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions.
Main projections
The future warming by 2100 – with comparable emission scenarios – is about the same as projected in the previous IPCC assessment report.
For the highest scenario, however, the best-estimate warming by 2100 is still 4 °C.
Since the First assessment Report in 1990, a progression in the understanding if the climate change by the IPCC is noticeable. In particular, it is now considered even more certain (> 95%), that human influence has been the dominant cause of the observed warming since the mid-20th century.
The likelihood of further changes, such as extreme weather and climate events, is currently assessed as “Virtually certain”.
Sea levels are rising faster now than the mean rate over the previous two millennia, and the rise will continue to accelerate regardless of the emissions scenario, even with strong climate mitigation. This is due to the inertia in the system.
The 5th assessment report also includes a Regional Atlas.
The IPCC expects that in the Mediterranean and Middle East region, temperature increase will cause dry areas to become drier and climate change could have an important impact even with a successful adaptation.
Reference documents
The Fifth Assessment Report (AR5) provides a clear and up to date view of the current state of scientific knowledge relevant to climate change. It consists of three Working Group (WG) reports and a Synthesis Report (SYR) which integrates and synthesizes material in the WG reports for policymakers.