LONDON, Oct 30 — Updated maps based on the referential Köppen-Geiger climate classification method show that major changes in climate and precipitation are set to occur all over the world. And these shifts will start to be seen in the next few decades.

A new study published in Nature magazine predicts the major changes likely to occur on the planet over the next 70 years. Carried out by an international group of researchers, it is based on the Köppen-Geiger classification method, a global reference for categorising climates worldwide, according to criteria such as seasonality of air temperature and monthly precipitation. Developed at the end of the 19th century by Russian-German climatologist Wladimir Köppen, then refined by meteorologist Rudolf Geiger, this system divides the world’s terrestrial climates into five main categories.

The study mentioned here is an updated version of the Köppen-Geiger maps available online. It was based on data and projections for a period of two centuries, between 1901 and 2099, divided into several year segments (1901-1930, 1931-1960, 1961-1990, 1991-2020, 2041-2070 and 2071-2099). Based on some 60 climate models, it shows the extent to which climates around the world have changed or are likely to change in the future as a result of global warming. Only the scenarios with the most plausible CO2-induced warming rates have been selected for the maps corresponding to the years 2041-2070 and 2071-2099.

The results of this research estimate that annual minimum and maximum monthly air temperature are set to increase across the globe, "particularly minimum air temperature at higher latitudes.” More specifically, 2.6 million sq km (equivalent to the size of Argentina, the world’s eighth largest country) could transition from polar to cold by 2071-2099, while 2.4 million sq km will change from cold to temperate, 1.1 million sq km from cold to arid, and 2.8 million sq km from temperate to tropical.

Average precipitation is set to fall in Central America, the Mediterranean basin, southern Africa and Australia, and to rise elsewhere in emerging regions. "The uncertainty in mean precipitation projections is less for the Model Subset than for All Models over most of the globe, except for Australia and parts of the US, northern Europe, Africa, and the Middle East,” notes the study. — ETX Studio