Estimating climate threats to biodiversity

Metrics that synthesize the complex effects of climate change are essential tools for mapping future threats to biodiversity and predicting which species are likely to adapt in place to new climatic conditions, disperse and establish in areas with newly suitable climate, or face the prospect of extirpation.

In a study published this week researchers have used high-performance computing methods and comprehensive data on the distribution of thousands of species to map the threat that climate change poses to birds, mammals and amphibians across the Western Hemisphere. They searched for and categorized millions of images, using approaches similar to those developed for facial and fingerprint recognition software. This allowed them to sift through millions of pixels representing future climate at different locations to determine each site's current climate fingerprint.

By incorporating data on the climate tolerances of individual species, the researchers were able to fine-tune their initial estimates of dispersal based on climate change alone. This combination of climate data and biological data showed that although polar regions currently are experiencing the greatest shifts in climate, species in the Amazon basin face the greatest threats because of the narrow range of conditions they can tolerate and the longer distance to cooler habitat that can serve as climate refuges.

These results suggest that tropical species will likely be some of the most vulnerable to climate change. While we know that many of these species are restricted to relatively narrow climatic ranges, combining this information with detailed maps of where and how climate is shifting most rapidly provides a much clearer picture of where threats are greatest.

As climate shifts over the coming decades, such "velocity of climate change" information can help predict which species are likely to adapt in place to new climatic conditions, disperse and establish in areas with newly suitable climate, or face the prospect of extinction. It would allow us to estimate the actual distance and speed it would take for an animal to disperse across the landscape to stay within its climate tolerances and survive in the face of climate change. For example, the Amazon's yellow-banded poison dart frog is projected to have to move several hundreds of kilometers to the southwest, because most of its range will likely become unsuitable for this species to live. Several other amphibian species in this region show similar movement patterns.

This study is the first time that scientists have been able to accurately estimate the velocity of climate change for thousands of species over entire continents. Even as governments step up their commitment to reduce future greenhouse gas emissions, this information can help planners identify climate refuges where conservation would reduce loss of species from the climate change that is already locked into the system from past emissions.