The Royal Society and the US National Academy of Sciences, with their similar missions to promote the use of science to benefit society and to inform critical policy debates, offer this new publication as a key reference document for decision-makers, policymakers, educators, and other individuals seeking authoritative answers about the current state of climate-change science. Questions addressed include:

If the world is warming, why are some winters and summers still very cold?

What are scientists doing to address key uncertainties in our understanding of the climate system?

Other Authoring Institutions