Global warming to expose more people to Zika-spreading mosquito Aedes aegypti

Source: Andrew Monaghan, The Conversation, June 16, 2016

As Americans ready themselves for the arrival of mosquitoes this summer, many may be wondering whether they are at risk for tropical diseases like Zika and whether climate change will raise the risks of infection.

My colleagues and I recently completed a study examining how projected changes in climate and human population may increase global exposure to the mosquito that spreads these viruses: Aedes aegypti.
We found that both climate change and human population change will play a part in driving future human exposure to Aedes aegypti globally. In the United States, specifically, warming temperatures from climate change mean that this disease-spreading mosquito will be increasingly abundant in the southern and eastern U.S….
The potential impacts of 21st century climatic and population changes on human exposure to the virus vector mosquito Aedes aegypti
Source: Andrew J. Monaghan, K. M. Sampson, D. F. Steinhoff, K. C. Ernst, K. L. Ebi, B. Jones, M. H. Hayden, Climatic Change, First Online: 25 April 2016
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From the abstract:
The mosquito Aedes (Ae). aegypti transmits the viruses that cause dengue, chikungunya, Zika and yellow fever. We investigate how choosing alternate emissions and/or socioeconomic pathways may modulate future human exposure to Ae. aegypti. Occurrence patterns for Ae. aegypti for 2061–2080 are mapped globally using empirically downscaled air temperature and precipitation projections from the Community Earth System Model, for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Population growth is quantified using gridded global population projections consistent with two Shared Socioeconomic Pathways (SSPs), SSP3 and SSP5. Change scenarios are compared to a 1950–2000 reference period. A global land area of 56.9 M km2 is climatically suitable for Ae. aegypti during the reference period, and is projected to increase by 8 % (RCP4.5) to 13 % (RCP8.5) by 2061–2080. The annual average number of people exposed globally to Ae. aegypti for the reference period is 3794 M, a value projected to statistically significantly increase by 298–460 M (8–12 %) by 2061–2080 if only climate change is considered, and by 4805–5084 M (127–134 %) for SSP3 and 2232–2483 M (59–65 %) for SSP5 considering both climate and population change (lower and upper values of each range represent RCP4.5 and RCP8.5 respectively). Thus, taking the lower-emissions RCP4.5 pathway instead of RCP8.5 may mitigate future human exposure to Ae. aegypti globally, but the effect of population growth on exposure will likely be larger. Regionally, Australia, Europe and North America are projected to have the largest percentage increases in human exposure to Ae. aegypti considering only climate change.