Climate change and diseases
Climate change has already boosted the spread of diseases that kill about half a million people every year: malaria, dengue, chikungunya, zika. "Mosquitoes moving their range north are now able to overwinter in some temperate regions. They also have longer breeding periods,” said Jeanne Fair, deputy group leader for biosecurity and public health at the Los Alamos National Laboratory in New Mexico in a report by Agence France-Presse.
ALSO READ| This Country Promises To Provide Free Covid-19 Vaccines To Each Citizen Once Manufactured
The dengue-bearing mosquito, Aedes aegypti, has appeared in Europe and the Europe Centre for Disease Prevention and Control (ECDC) has registered 40 cases of local transmission of dengue between 2010 and 2019.
According to Cyril Caminade, an epidemiologist working on climate change at the Institute of Infection and Global Health at the University of Liverpool said that these signals for communicable tropical diseases "are worrying in terms of expanding vectors, not necessarily transmission."
Can Ancient Viruses Come To Life?
Permafrost is like a climate change time bomb spread across Russia, Canada, and Alaska that contains three times the carbon that has been emitted since the start of industrialisation. And permafrost has its own hidden treasures.
According to Vladimir Romanovsky, a professor of geophysics at the University of Alaska in Fairbanks who was quoted in Agence France-Presse report, "Microorganisms can survive in frozen space for a long, long time.”
Jean-Michel Claverie, an emeritus professor of genomics at the School of Medicine of Aix-Marseille University in France talked about how viruses can come back to life after being frozen for years. His lab has successfully revived Siberian viruses that are at least 30,000 years old.
These reanimated bugs only attack amoebas, but there were viruses that climbed higher in the food chain which can come back to life. "When you put a seed into soil that is then frozen for thousands of years, nothing happens. But when you warm the earth, the seed will be able to germinate. That is similar to what happens with a virus," said Claverie in the report.
ALSO READ| This Is What ICMR Said About Emergency Authorisation For Covid-19 Vaccine And Testing From Gargled Water
According to the UN's climate science panel, the IPCC, even capping global warming at under two degrees Celsius which was the cornerstone goal of the 2015 Paris Agreement, the permafrost area will decrease by a quarter by 2100.
When the ground thaws all these once frozen microorganisms will come in contact with the present-day environment by the flows of water. These microorganisms can come back to life as Claverie’s lab tested. "Neanderthals, mammoths, woolly rhinos all got sick, and many died. Some of the viruses that caused their sicknesses are probably still in the soil, “said Claverie.
While bacteria and viruses lurking in the permafrost are incalculable, the more important question is how dangerous they are.
And here, scientists have a difference in opinion. For example, researchers in Sweden give the example of anthrax an infection caused by a bacteria. “Anthrax shows that bacteria can be resting in permafrost for hundreds of years and be revived," said Birgitta Evengard, a researcher in clinical microbiology at Umea University in Sweden.
It is worth noting that in 2016, a child in Siberia died from Anthrax, which had disappeared from the region at least 75 years earlier so it can be attributed to the thawing of the carcass. But some experts think the animal remains in question may have been in shallow dirt and thus subject to periodic thawing.
While vaccines are available today for many of the diseases such as smallpox, the real danger is from unknown pathogens in the deeper strata that have not seen daylight for two million years or more and which may be exposed by global warming.