Background
The authors write that "pathogens cause roughly one in five human deaths, are responsible for 51% of years of life lost globally and have long affected human demographics." They say that pathogens "have also been identified as drivers of human behavior, the politics and political stability of countries, human fertility, global economies, and more generally the course and dynamics of human history." And, somewhat ominously, they state that "researchers have linked the presence and prevalence of some pathogens to climate, as has been highlighted in recent discussions of climate change and disease," where they specifically mention malaria, plague and dengue as examples of the latter.

What was done
Dunn et al. conducted, as they describe it, "a global analysis of the relative influence of climate, alternative host diversity and spending on disease prevention on modern patterns in the richness and prevalence of human pathogens."

What was learned
The U.S., Canadian and New Zealand researchers report that "pathogen richness (number of kinds) is largely explained by the number of birds and mammal species in a region," and that "the most diverse countries with respect to birds and mammals are also the most diverse with respect to pathogens." And noting, in this regard, that "we are unlikely to be able to change patterns of pathogen richness dramatically," they go on to state that "pathogen richness, even when high, does not guarantee high prevalence, because of the potential impact of disease control effort." In fact, they find that "pathogen prevalence is much more sensitive to variation in health spending among regions," and that "importantly, for human health, the prevalence of key human pathogens is strongly influenced by disease control efforts."

What it means
As a consequence of the above observations, Dunn et al. conclude that "even where disease richness is high, we might still control prevalence, particularly if we spend money in those regions where current spending is low, prevalence is high and populations are large." And let's be realistic about it: this approach is infinitely more likely to succeed in its worthy objectives than is the nebulous idea (i.e., the wishful thinking) of changing the planet's climate. And with all of the unanticipated consequences -- many of which may be assumed to be negative and are almost assured to occur with the undertaking of such a huge and complex campaign -- we could well be better off to do nothing than to gamble all that the human family has achieved over the millennia, fighting a war against something so ethereal as anthropogenic-induced global warming.