High altitude areas may become wildlife refuges due to climate change

As climate change progresses, its impacts are not uniform across the board, with temperature rising differently by 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 in China and colleagues investigated the role that altitude plays in climate heterogeneity by analyzing changes in organismal diversity using the Shannon Diversity Index and the Köppen-Geiger climate classification. The latter divides climate into tropical, arid, temperate, continental and polar regions based on seasonal rainfall and temperature links to vegetation distribution.

These temperature and precipitation data were derived from more than 4,000 weather stations around the world over a 70-year period beginning in 1952. Topography adds further complexity, as surface roughness and elevation can affect surface temperature, precipitation, the hydrologic cycle, energy budgets and vegetation cover that can create a mosaic of five climate groups. This project surveyed nine altitudes from 0 m to over 4,000 m at 500 m intervals.

The research team’s key finding is that the Shannon Diversity Index decreases at low altitudes (less than 2,000 m) where temperatures rise higher and faster, leading to the spread of similar arid and tropical conditions over a wide area.

In comparison, higher elevations (above 2,000 m) show greater climatic heterogeneity, meaning that the diversity index continues to increase amid initially cooler but steadily slowly warming environmental conditions until only small patches of cold climate remain at topographic highs .

In addition, the researchers used climate simulations to test what was driving these patterns and unsurprisingly identified anthropogenic climate change as the driver of this marked shift in climate heterogeneity between lower and higher elevations.

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

Meanwhile, the cooler high-altitude refugia identified include the Qinghai-Tibet Plateau at more than 4,100m, which is predicted to reach 5.9°C in 2070–2098, but is already warming twice at an increased rate of 0.44°C in a decade. global average.

This research is significant because projections suggest that up to 46% of Earth’s land surface may 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.

Understanding the climate variability that persists at higher altitudes could therefore mean that in the years to come they become refuges for human, animal and plant communities as they seek more favorable conditions away from rising temperatures and the wealth of social, economic and ecological problems that result. result. .

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