For a tree in the Amazon, one of the leading causes of death is being knocked down by the strong wind associated with storms. By some estimates, these "windthrow" events account for about half of tree mortality in the Amazon. Here, we make a first pass at estimating how this mortality rate will change due to the intensification of storms caused by global warming.
Observations show that the frequency of windthrow events are a nearly binary function of the convective available potential energy (CAPE; a measure of potential storm intensity). Windthrows occur in locations with average CAPE exceeding about 1000 J/kg, but not to any appreciable degree for CAPE values below that threshold. Using global climate models, we can calculate the increase in the Amazon's area that has an average CAPE above this threshold. We find an increase in area of about 50% by the end of the century, suggesting that about 50% more of the trees will face death by windthrow as a leading cause of mortality.
Density of 1012 windthrow events on a 2.5° by 2.5° grid as observed using Landsat 8 images. This pattern closely matches the distribution of average CAPE.