Here is an irresponsible (but not necessarily inaccurate) blog post (from ThinkProgress):
Climate change death toll ‘to double within 25 years.’That's it. That's the whole thing. Needless to say, the comments section over there is all stirred up.
“Deaths and injuries from climate change are set to more than double in the next 25 years, according to estimates” by the World Health Organization. Deaths “linked to even a very narrow number of causes most closely connected to shifting weather patterns will reach more than 300,000 a year by 2030.”
The original article from the Financial Times cites some WHO data which points to "deaths inked to even a very narrow number of causes most closely connected to shifting weather patterns." I think that asserting such data as highly accurate is difficult because of the indirect relationship between climate change and individual weather events which haven't happened yet. I've said it a million times- climate is not weather. Although we could predict a mean of hurricane intensity or frequency over the next twenty years, we can't predict whether another one will hit New Orleans or Miami or Houston years ahead of time. Furthermore, populational and geopolitical issues have a huge role in predicting these deaths (e.g. migrations, emergency response, food supply) and thus the uncertainty grows.
Here's a good analogy for this type of report: What if you were to estimate the number of people killed by "poverty" in the United States over the next 20 years? This would seem difficult, because you would have to figure in deaths from poor medical treatment, deaths from exposure (for the homeless), deaths from malnutrition and maybe even deaths from drug-related gun violence. Is poverty the actual cause of death? No. But poverty is arguably the principal underlying cause. Climate change works the same way- a two degree rise in temperature may not kill anybody, but the hurricane resulting from more intense tropical ocean convection just might.
The issue here isn't the WHO report, which is surely based on broad estimates and designed to be preliminary and cautionary. The issue is that ThinkProgress presented the story so sensationally in a forum where people are looking for stories like these to confirm their biases. This is not good reporting, nor is it informative.
[ThinkProgress: Climate Change Toll to Double in 25 years]
[Financial Times: Climate Toll Will Double by 2030]