Two major developments this month have brought the issue of human-induced climate change to the attention of the global community. The first was the release of the Intergovernmental Panel on Climate Change synthesis report (SR). The second, the agreement between the US and China to limit emissions of greenhouse gases (GHG) in both countries, reached after a prolonged period of quiet diplomacy between the two. The US-China agreement is an encouraging development that, it is expected, will motivate other countries to also make commitments to reduce GHG emissions. But as the findings of the SR clearly indicate, much more needs to be done to limit temperature increase to 2 degrees Celsius by the end of this century.
The SR, a document written for a non-specialist audience, released on November 2 in the presence of the UN Secretary General Ban Ki-moon, carries the essence of the major scientific findings of the IPCC’s recently completed working group reports, and two special reports dealing with renewable energy and extreme events and disasters, respectively. The 40-page summary for policymakers extracts the relevant essence of almost 7,000 pages of published IPCC reports on which it is based.
This report updates our knowledge substantially on various aspects of climate change. For instance, it is stated with over 95 per cent confidence that human actions have been largely responsible for climate change since the middle of the last century. It also assesses scenarios for future climate change and related impacts, and finds that continued emission of GHGs will cause further warming and longlasting change in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems. Limiting climate change will require substantial and sustained reductions in GHG emissions which, together with adaptation, can limit climate change risks.