A bunch of Aussie mosquito nerds or "entomologists" as they prefer to be called, have just looked at the constantly iterated claims that climate change will cause an increase in arboviruses like Dengue fever across Australia. They discovered that:
"...the dengue vector (the Aedes aegypti mosquito) "was previously common in parts of Queensland, the Northern Territory, Western Australia and New South Wales," and that it had, "in the past, covered most of the climatic range theoretically available to it," adding that "the distribution of local dengue transmission has [historically] nearly matched the geographic limits of the vector."
They conclude that ...
The vector's current absence from much of Australia, "is not because of a lack of a favorable climate." Thus, they reason that "a temperature rise of a few degrees is not alone likely to be responsible for substantial increases in the southern distribution of A. aegypti or dengue, as has been recently proposed." ... "dengue activity is increasing in many parts of the tropical and subtropical world as a result of rapid urbanization in developing countries and increased international travel, which distributes the viruses between countries."
(Russell, R.C., Currie, B.J., Lindsay, M.D., Mackenzie, J.S., Ritchie, S.A. and Whelan, P.I. 2009. Dengue and climate change in Australia: predictions for the future should incorporate knowledge from the past. Medical Journal of Australia 190: 265-268.)
For many of us climate skeptics, when we're not going to board meetings of Fortune 500 companies or relaxing on our country estates, there was a key moment when we thought "Wait a minute! That ain't right!" about a particular piece of information. Then we started to question the information being presented to us on climate change, asked some awkward questions, and before you knew it, the whole house of cards came tumbling down.
For me, that pivotal first moment was in a lecture on malaria. The lecturer was actually a well regarded malaria researcher who had been published in Nature (although I lost my faith in the peer review process right around the time they published a paper that predicted that all fish life would die out in 10 years time). He had displayed a slide of what they claimed was an Anopheles mosquito and then told us that due to global warming we would see an increase in mosquito borne diseases in Australia in the future.
My first thought was "Wait a minute! Thats not an Anopheles mosquito. Im no expert, (but I am a nerd) and that looks like an Aedes." Which kind of called into question his expertise as a malaria researcher as far as I was concerned. The next few thoughts went a bit like this:
- Hang on. Ive got suitable malaria and arbovirus vectors in my backyard here in southern Australia. The bloody agapanthuses (agapanthii?) are full of them.
- All of the arbo viruses (and Australia has several endemic varieties of our own) are notifiable illnesses.[i] Not only do the public health mob keep close tabs on cases, but the mosquito boffins do, too[ii], and this widely available information would indicate that not only are mosquito vectors found in all parts of Australia, but an overwhelming amount of cases are found in suburban southern Australia. Even Tasmania has the odd case, and it is almost equidistant between Antarctica and the tropical north of the country. (Re: Mosquito scientists. These are serious insect pervs, they have web sites where you can listen to the wing noise made by different species of mozzie. They must be telling the truth.)
- Australia was only declared free of malaria by the WHO in 1981[iii], and has had several locally contracted cases since then[iv] [v]. Climate in any of its guises did not rid Australia of malaria, good public health did.
- Additionally, even the briefest familiarity with medical history would indicate that there have been massive mosquito-borne disease outbreaks throughout history, even approaching arctic latitudes. Anyone who denies that mosquitoes are happy in sub polar regions hasn’t seen those nature documentaries of caribou choking to death on summer mosquito clouds. Oliver Cromwell was unfortunate enough to have died of what was probably tertiary malaria in England in 1658, which corresponds to part of what climatologists frequently refer to as “the Little Ice Age.”[vi]
It’s fair to say that I am by no means an expert on these matters, so it was gratifying to discover that some of those who are actually qualified to comment on this have issues of their own. See this talk by Paul Reiter, a medical entomologist who withdrew from the IPCC. (The last bit of the talk is particularly worth it just to see him stick it to Al "The Goracle" Gore).
[i] Arbovirus and Malaria Surveillance, Department of Health and Ageing.
[ii] The NSW arbovirus surveillance and mosquito monitoring project.
[iii] World Health Organization. Synopsis of the world malaria situation in 1981. Wkly Epidemiol Rec 1983; 58: 197-199.
[iv] Locally-acquired Plasmodium falciparum malaria on Darnley Island in the Torres Strait. Communicable Diseases Intelligence, Volume 25, Issue number 3 - August 2001
[v] Brookes et al. Plasmodium vivax malaria acquired in far north Queensland. MJA 1997; 166: 82
[vi] Reiter, P. From Shakespeare to Defoe: Malaria in England in the Little Ice Age. Emerging infectious diseases. Vol. 6, No. 1, January–February 2000.