As temperatures rise due to climate change, animals may have to move to cooler areas in order to survive. A research paper published June 9th in Scientific Reports predicted that this will be especially true in the tropics. Solomon Hsiang, from the University of California, worked with Adam Sobel from Columbia University to develop a mathematical model to quantify these predictions.
The tropics tend to remain around the same temperature all year. Since areas along the equator are already hot, a tiny temperature change is enough to stress the local wildlife. Hsiang and Sobel found that even a temperature increase of 2°C would be enough to force many plants and animals to move to cooler locations. Both marine and terrestrial species may have to move more than 1,000 km per 2°C temperature increase. According to their model, many of these plants and animals will end up along the margins of the tropics or in subtropical areas, where the temperatures can be much milder. The authors of the paper predict that populations may increase by 300% in those areas.
As the outer parts of the tropics get more crowded, competition for food and other resources will become a huge problem. The local ecosystems may not be able to support such a sharp population increase and crowded conditions may lead to disease and aggression. As more and more animals are forced to move, the environmental conditions would only get worse.
Some species wouldn’t be able to evacuate at all. Plants and animals not capable of moving easily, such as coral reef inhabitants, would be at risk of serious harm or even extinction. Others may be able to leave but won’t be able to travel fast enough. Hsiang and Sobel also point out that they used a best case scenario climate model. In reality, temperatures are likely to increase faster and the consequences will be more dramatic than their predictions.
Climate change is likely to affect most of life on Earth but these new findings suggest that the tropics will be especially at risk. Further research will be needed to predict actual migration patterns and how individual species will react to global warming.
Solomon M. Hsiang et al. Potentially Extreme Population Displacement and Concentration in the Tropics Under Non-Extreme Warming, Scientific Reports (2016).