CO2 Science reviews a study showing that the appearance of high levels of extinction due to shifts in climate is due to the coarse resolution of the grid cells used in the simulations. This is another vindication of the conclusion of our 18 author collaboration.
When grid cells are coarse, a one degree shift in temperature, say, affects a large area, and can appear to eliminate all habitat for a species in the grid cell. The virtual species must move a long way to find another suitable grid cell. In actuality each coarse grid cell contains a range of temperatures. When the grid cells are finer, there will most likely be areas within the grid cell with suitable habitat for the species, enabling it to persist through large climate variations.
Refugia are well known to have a crucial role in species’ persistence, and may be characterized as areas of high spatial heterogeneity. It is easy to see that choice of scale would have a large effect on determinations of species persistence, and great caution would be needed in interpreting results of simulations conducted on coarse grids.