The article also claims that a rise in kidney disease in El Salvador is related to global warming without offering any evidence whatsoever. Correlation is not causation, right? I think that one specious claim undermines the entire article, quite frankly. El Salvador is a nation with all kinds of social problems including a population that is under-educated (to say the least) so I find it hard to believe that heat is the biggest problem there versus dirty water, ignorance of the need to stay hydrated, etc.
Extensive data with multiple very strong correlations, a very plausible biological explanation, and a perfect animal model. There is way, way more here than conjecture.