High altitude regions can become wildlife refuges through climate change

As climate change progresses, its impacts are not universally equal, with temperature increasing differently across latitude and altitude. Climate heterogeneity is the study of this diversity in Earth’s climate patterns and the focus of recent research published in Geophysical Research Letters.

Yanlong Guan, of Fujian Agriculture and Forestry University, China, and colleagues investigated the role that altitude plays in climate heterogeneity by analyzing changes in organismal diversity via the Shannon diversity index and the Köppen-Geiger climate classification. The latter divides the climate into tropical, arid, temperate, continental and polar regions based on seasonal relationships of rainfall and temperature with the distribution of vegetation.

Such temperature and precipitation data are derived from more than 4,000 weather stations globally over a 70-year period, beginning in 1952. Topography adds further complexity to this as surface roughness and elevation can affect the temperature of surface area, precipitation, hydrological cycle, energy budgets and vegetation cover that can create a patchwork of five climate groups. This project investigated nine elevations from 0 m to more than 4,000 m at 500 m intervals.

The main finding of the research team is that the Shannon diversity index decreases at low altitudes (less than 2000 m) where temperatures rise higher and faster, leading to the spread of similar dry and tropical conditions in a space. wide area.

In comparison, higher elevations (greater than 2,000 m) exhibit greater climatic heterogeneity, meaning that the diversity index continues to increase between initially cooler but persistently slow warming environmental conditions, until only parts small portions of cold climates remain at topographic elevations.

Additionally, the scientists used climate simulations to test what was driving these patterns, surprisingly pinpointing anthropogenic climate change as the driver of this particular change in climate heterogeneity between lower and higher elevations.

These simulations also extrapolated climate heterogeneity through century recall, identifying locations that may experience reduced climate variability, such as North America which is at an average elevation of ~1600 m and is projected to experience an average temperature of 14.2°C .

Meanwhile, the coldest high-elevation refugia identified include the Qinghai-Tibet Plateau at more than 4100 m, which is projected to experience temperatures of 5.9°C during 2070–2098, but is already warming at an increased rate of 0.44°C per decade, twice. the global average.

This research is significant as projections suggest that up to 46% of the earth’s land surface could shift to warmer and drier conditions by the end of the century, with this homogenization of climate types potentially threatening the distribution of habitats and species.

Therefore, understanding the climate variability that persists at higher altitudes could mean that they become shelters for human, animal and plant communities in the years to come as they seek more favorable conditions away from rising temperatures and a wealth of social issues. , economic and environmental that follow. .

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