“Aedes aegypti CDC-Gathany” by James Gathany – PHIL, CDC. Licensed under Public Domain via Commons.The New York Times has just published an article claiming that global warming is (partly) to blame for the spread of various “tropical” diseases to the U.S. and other areas where previously they had been eradicated or had never existed. Donald G. McNeil Jr. begins his article titled “U.S. Becomes More Vulnerable to Tropical Diseases Like Zika” thus:
Tropical diseases — some of them never before seen in the United States — are marching northward as climate change lets mosquitoes and ticks expand their ranges.
A little farther along he concedes that other causes probably contribute, too:
Some factors in the new spread are, for now, unstoppable, scientists say: the weather is hotter; cheap airfares mean humans travel more than they did decades ago; and cities in tropical countries are becoming more crowded, creating nurseries for each disease.
I am extremely skeptical of any claim that the spread of these diseases is affected significantly by global warming.
First, there’s been no statistically significant increase in global average temperature since February of 1997, 18 years and 10 months ago, which makes changes more recent than that very difficult to tie to any warming trend.
Second, the slight increase that did occur in global average temperature (GAT) over the previous 20 years, precisely because it was in global AVERAGE temperature, would have made little difference in local temperatures, and local temperatures are what affect vector (insect and other germ carrier) survival.
Third, according to the climate models on which the climate alarmists rely, most of the increase in GAT was embodied in warming in the North Polar region, and the empirical data support that, which means little of the increase in GAT was left to occur in the regions in which the vector and disease spread are identified.
Fourth, the two other causes mentioned in the report — “cheap airfares mean humans travel more than they did decades ago; and cities in tropical countries are becoming more crowded, creating nurseries for each disease” — are far more likely to explain the spread of the diseases than the climate change that hasn’t happened for nearly 20 years.
The impression that malaria, for instance, is a “tropical disease” is completely false. It was endemic in over 40 of the 48 contiguous United States, plus Alaska. The biggest malaria epidemic in history was in Siberia. It’s essentially a disease of poverty. Other vector-borne diseases are likely the same.
So chalk this up to another instance in which the mainstream media automatically blame a problem on AGW when the evidence for the connection is thin to nonexistent.
The report also predictably avoids any mention of DDT, either as a potential response to the current risks or as the means by which we eliminated malaria from the South here in America. Note this paragraph: “The importance of living conditions and medical treatment is exemplified by malaria. It once was widespread in the South and ranged as far north as Boston in hot summers.” No mention at all of why it disappeared from the South, but it was by widespread and intensive use of DDT spraying.
