The idea that climate change would bring malaria back to lands where it has long been eradicated didn’t originate with Al Gore. He certainly got a lot of mileage out of it in his now thoroughly forgotten 2006 movie An Inconvenient Truth, but in 1999 a paper had appeared in the journal Global Environmental Change entitled “Climate change and future populations at risk of malaria” which, as the title suggests, was about how we were all going to get the dreaded tropical scourge as temperatures started rising. They warned that “The greatest proportional changes in potential transmission are forecast to occur in temperate zones, in areas where vectors are present but it is currently too cold for transmission.” Not, mind you, based on observed trends, but on model projections. Their model said that by 2080 another 450 million people around the world would be at risk of catching the disease. But sometimes the key to having it both ways in climate science is for someone to look away from the models long enough to examine actual observed trends.

It took a little over a decade. But eventually a paper appeared in Nature magazine (of all places) pointing out that despite all the hysteria about climate change and malaria, the dratted disease just kept disappearing due to routine control measures:

“A resurgence in funding for malaria control, the existing efficacy of affordable interventions, and a growing body of nationally or sub-nationally reported declines in endemicity or clinical burden have engendered renewed optimism among the international malaria research and control community. In marked contrast, however, are model predictions, reported widely in global climate policy debates, that climate change is adding to the present-day burden of malaria and will increase both the future range and intensity of the disease. In policy arenas, such predictions can support scenario analysis or serve as a call to action, but the modelling approaches used and the accuracy of their predictions have not always been challenged.”

Hmmm. The models say one thing, which the press then happily amplifies, but the data say another. The authors reviewed the actual trends in malaria incidence around the world since the start of the 20th century and pointed out that despite some warming, malaria had retreated substantially. Hence, they reasoned, even if warming continues in the future there is no reason to think that malaria trends will reverse.

So climate change isn’t going to matter in the future any more than it did in the past, which was not much at all:

“The quantification of a global recession in the range and intensity of malaria over the twentieth century has allowed us to review the rationale underpinning high-profile predictions of a current and future worsening of the disease in a warming climate. It suggests that the success or failure of our efforts against the parasite in the coming century are likely to be determined by factors other than climate change.”

An insight which, we believe, applies to many other issues besides malaria. As is the point that on climate change, data don’t seem to matter because you so often get to #HaveItBothWays.