Heatstroke

March 16, 2009
Around the world, climate change is indicated by natural events-especially in shifting migration routes-leading to results familiar (species die-out) and unexpected-like the discovery of a heretofore unprecedented "pizzly," a bear cub with one polar parent and one grizzly. Not all geographical displacement is quite so friendly; as ""ecological niches are shriveling up and disappearing," common and persistent species are dying off at a rate "between 17 percent and 377 percent faster than normal" over the past 400 years. While reviewing the evidence that points to drastic changes resulting from even small global temperature increases, Barnosky also discusses biodiversity's importance, compares rates of evolutionary change with global temperatures, and recounts Earth's four previous mass extinctions. One of her grim assessments is that "many of the species that humans tend to like" will be wiped out by global warming, and spur helpful evolutionary diversification only in "what we normally call pests." For the most part Barnosky is less gloomy than curious, able and straight-forward, flavoring his report with a sense of adventure and possibility; by the end of his discussion on humanity's four-pronged problem-global warming, habitat loss, introduced species and population growth-Barnosky will have readers looking to do more than change lightbulbs.