|Cover of the last IPCC report 'Climate Change 2013: The Physical basis'. Source: IPCC|
On Friday, the IPCC published its last report. Probably, you have listened or read something about it during these days. What is the IPCC? and (2) What is this report about?
The IPCC is the Intergovernmental Panel on Climate Change (IPCC). It was established in 1988 by the United Nations Environment Programme (UNEP) and the World Meteorological Organization (WMO) to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts. How? The IPCC reviews and assesses the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change. Thousands of scientists from all over the world contribute to the work of the IPCC, bringing their expertise in the many different disciplines necessary to produce a comprehensive assessment of climate change on a voluntary basis. For the preparation of the last report on ‘Climate Change. The Physical Science Basis’, a total of 259 Lead Authors and 50 Review Editors from 39 countries and more than 600 Contributing Authors from 32 countries contributed. You can download the report here.
According to the information published on this last report, I want to resume some of things that we 'certainly know' about climate change based on what the last decades of observations tell us. Why do I remark the fact that ‘we certainly know’? Because the report is cautiously written. It means that consensus is necessary among the scientists that contribute to the report when the degree of certainty in key findings is expressed from very low to very high and from exceptionally unlikely to virtually certain. Thus, findings considered virtually certain are supported by data, theory, models, etc. and the scientific consensus. Those are some of these findings.