Guest essay by Eric Worrall
Any change is bad? according to a new study, warming in cold climates or cooling in warm climates increases the risk of animals getting sick, which in turn increases human exposure to dangerous new pathogens.
Global warming likely to increase disease risk for animals worldwide
Date: November 23, 2020
Source: University of Notre Dame
Summary: Changes in climate can increase infectious disease risk in animals, researchers found — with the possibility that these diseases could spread to humans, they warn.
Changes in climate can increase infectious disease risk in animals, researchers found — with the possibility that these diseases could spread to humans, they warn.
The study, conducted by scientists at the University of Notre Dame, University of South Florida and University of Wisconsin-Madison, supports a phenomenon known as “thermal mismatch hypothesis,” which is the idea that the greatest risk for infectious disease in cold climate-adapted animals — such as polar bears — occurs as temperatures rise, while the risk for animals living in warmer climates occurs as temperatures fall.
The hypothesis proposes that smaller organisms like pathogens function across a wider range of temperatures than larger organisms, such as hosts or animals.
“Understanding how the spread, severity and distribution of animal infectious diseases could change in the future has reached a new level of importance as a result of the global pandemic caused by SARS-CoV-2, a pathogen which appears to have originated from wildlife,” said Jason Rohr, co-author of the paper published in Science and the Ludmilla F., Stephen J. and Robert T. Galla College Professor and chair of the Department of Biological Sciences at Notre Dame. “Given that the majority of emerging infectious disease events have a wildlife origin, this is yet another reason to implement mitigation strategies to reduce climate change.”
…Read more: https://www.sciencedaily.com/releases/2020/11/201123161032.htm
The abstract of the study;
Divergent impacts of warming weather on wildlife disease risk across climates
Climate change alters disease risks
Climate change appears to be provoking changes in the patterns and intensity of infectious diseases. For example, when conditions are cool, amphibians from warm climates experience greater burdens of infection by chytrid fungus than hosts from cool regions. Cohen et al.undertook a global metanalysis of 383 studies to test whether this “thermal mismatch” hypothesis holds true over the gamut of host-pathogen relationships. The authors combined date and location data with a selection of host and parasite traits and weather data. In the resulting model, fungal disease risk increased sharply under cold abnormalities in warm climates, whereas bacterial disease prevalence increased sharply under warm abnormalities in cool climates. Warming is projected to benefit helminths more than other parasites, and viral infections showed less obvious relationships with climate change.Read more: https://science.sciencemag.org/content/370/6519/eabb1702
The researchers’ inference that distress experienced by animals during unusual weather conditions can tell you anything about the impact of climate change seems dubious.
Why would animals which withstand seasonal temperature variations in the 10s of degrees will suddenly all sicken because of a rate of climate change which can barely be detected?
Even on the edge of the tropics where I live Winter is around 5-10C colder than Summer.
A proportion of animals are always at the edge of their range, they continuously move about and probe new ranges. It seems a big leap to infer that the gradual global warming we are experiencing would significantly increase the number of animals experiencing range distress. Global warming of 0.1C / decade is the climatic equivalent of moving South a few miles every year. Even a mouse can out walk climate change.