Modelling future no-analogue climate distributions: A world-wide phytoclimatic niche-based survey

By the end of the 21st century in some zones the accelerating climate change affecting this planet will create factorial combinations unknown at this time, which will give rise to climates unlike the present ones. This study presents a numerical and cartographic evaluation of these no-analogue climatic zones, whose consequences for existing ecosystems are quite unpredictable, using a method based on the convex hull in a climate hyperspace and 12 future climate projections for 2080. The percentage of the world surface that will foreseeably be occupied by no-analogue climates by 2080 ranges between 3.5% and 17.5%. The bulk of the no-analogue surface area will foreseeably be located in the Northern hemisphere (> 80%), with more elevated risk in tropical and subtropical latitudes between 10 degrees latitude South and 30 degrees latitude North, preferentially in Africa, South America, the Arabian Peninsula, the Indian Peninsula, the North-West of the Gulf of Mexico, Eastern China and Polynesia. Mean temperatures would appear to be the variables most influencing the process. This affects 32 of the 34 hotspots defined for the planet, especially tropical forests in South America and Asia. 6.8% of these conservation-critical surfaces are predicted as no-analogue areas. Population density is greater in the areas that will probably develop no-analogue climates in the future than in those that will not.