Climate change is thawing deadly diseases. Maybe now we'll address it? by Mona Sarfaty
Earlier this month, an outbreak
of anthrax in northern Russia caused the death of a 12-year-old boy
and his grandmother and put 90 people in the hospital. These deadly spores –
which had not been seen in the Arctic since 1941 – also spread to 2,300
caribou. Russian troops trained
in biological warfare were dispatched to the Yamalo-Nenets region to evacuate
hundreds of the indigenous, nomadic people and quarantine the disease.
Americans are likely
to associate anthrax with the mysterious white powder that was mailed to news
media and US Senate offices in the weeks following 11 September 2001. The bacteria
– usually sequestered in biological weapons labs – killed five people and
infected 17 others in the most
devastating bioterrorism attack in US history.
But in Russia, the
spread of illness was not the result of bioterrorism; it was a result of global
warming. Record-high temperatures melted Arctic permafrost and
released deadly anthrax spores from a thawing carcass of a caribou that had
been infected 75 years ago and had stayed frozen in limbo until now. This all
suggests that it may not be easy to predict which populations will be most
vulnerable to the health impacts of climate change.
In 2013, the National
Academy of Sciences hosted a forum on the influence of global environmental
change on infectious diseases. In his keynote
speech, Dr Jonathan Patz stood in front of a large slide of a mosquito and
warned: “Global warming’s greatest threat may also be the smallest.” The forum
focused on many causes of disease, from fungi, bacteria, viruses and mold
spores, to vectors like bats and mosquitoes. Climate change can exacerbate the
spread of infectious disease by changing the behavior, lifespans and regions of
diseases and their carriers.
This can sometimes be
hard to prove directly. It can be challenging, for example, to isolate the
avenues by which climate change drives emerging infections in warm climates
where travel, trade, land use and dense urban living can all lead to the spread
of disease. At other times, the signal is bright. Looking way up north in the
Arctic – where there are far fewer people, less travel and trade, and fewer
infectious diseases – the signal that climate change is a source of disease
outbreaks is clear.
It is usually so cold
in the tundra that the ground is perennially frozen in deep layers that can
date back 3m years. But the usual circumstances no longer apply at the top of
the world. The Arctic is warming twice as fast as the rest of the globe. In
fact, the area of the anthrax outbreak was 18F
(10C) hotter than average, with temperatures reaching 95F (35C).
In addition to releasing ancient microbes, melting layers of permafrost also
release methane, a greenhouse gas 30 times more potent than carbon dioxide,
that in turn causes further warming.
It is not just animal
carcasses that are thawing. Indigenous groups living in the tundra do not bury
their dead deep underground, opting instead for wooden coffins arranged in
above-ground cemeteries. This raises the potential for infections to spread
from this source as well.
Could some of the
severe infectious diseases that have threatened the planet in the past be
reactivated as our northernmost regions thaw? It’s not just climate scientists
that are concerned about the health threats of a warming world. Public health
experts and physicians are also speaking out. The Lancet Commission released
a report in 2015 asserting that climate change could reverse the last
50 years of public health advances. As risk is added to
risk, the signals of our changing climate underscore the urgent need to put
climate change solutions in place. Even more than we know, our health may
depend on it.
https://www.theguardian.com/commentisfree/2016/aug/24/climate-change-thawing-deadly-diseases-anthrax
