A simple climate change projection for the concerned public
This article is a preprint and is currently undergoing peer review by UCL Open: Environment.
Abstract
TheIntergovernmental Panel on Climate Change (IPCC) addresses policymakers with elaborateprojections that are difficult for most people to understand. The simplest modelis the recent trend in mean annual global warming, and the simplest projection isthe extrapolation of the trend line into the future. Amid the annual variationthe trend line is an index of the global mean warming at any one time, whereasthe IPCC’s method of estimation (the 20-year running mean) is retroactive. Untilnow the trend has been almost linear. Projected linearly into the future (aconservative projection if warming has begun to accelerate), the 50-year datagive results similar to the IPCC projections to mid-century, the 20-year data, whichhave a slightly more rapid rate of change, to less cautious published projections.A mean warming of 1.5C would be reached in 2032 and 2029 respectively. To plotthe graphs, and to decide how to project the trend lines into the future, is asimple exercise that avoids much complexity and is open to almost anyone to understandor to perform for themselves. It fosters critical thinking, lessening the gapbetween the public’s perception of climate change and that of climate scientists.
Keywords: Intergovernmental Panel on Climate Change, public understanding of science, climate change, global warming, global mean warming, simplicity.