It's

 

not just the glaciers.

The same thing happens as the artic permafrost melts.

(Permafrost: frozen layer on or under Earth's surface. It consists of soil, gravel, and sand, usually bound together by ice. Permafrost usually remains at or below 0°C (32ºF) for at least two years. Permafrost can be found on land and below the ocean floor.)

Never-before-seen microbes locked in glacier ice could spark a wave of new pandemics if released

"Stunned scientists have uncovered more than 900 never-before-seen species of microbes living inside glaciers on the Tibetan Plateau. Analysis of the microbes' genomes revealed that some have the potential to spawn new pandemics, if rapid melting caused by climate change releases them from their icy prisons."

"The team found 968 microbial species frozen within the ice — mostly bacteria but also algae, archaea and fungi, the researchers reported June 27 in the journal Nature Biotechnology. But perhaps more surprisingly, around 98% of those species were completely new to science. This level of microbial diversity was unexpected because of the challenges associated with living inside glaciers, the researchers said. "Despite extreme environmental conditions, such as low temperatures, high levels of solar radiation, periodic freeze-thaw cycles and nutrient limitation, the surfaces of glaciers support a diverse array of life," the study authors wrote.

"The researchers aren't sure exactly how old some of these microbes are; prior studies have shown that it is possible to revive microbes that have been trapped in ice for up to 10,000 years, according to the study."

(Im pretty sure thats the one I read about a few years back that was talking about microbes being released into the air when the permafrost thaws.) 

"The surprising microbial diversity within glaciers, coupled with an increase in melting glacial ice due to climate change, boosts the chances that potentially dangerous microbes — most likely bacteria — will escape and wreak havoc, researchers said. "Ice-entrapped pathogenic microbes could lead to local epidemics and even pandemics" if they are released into the environment, the authors wrote. 

"Evidence suggests that some of the newfound bacteria could be very dangerous to humans and other organisms. The team identified 27,000 potential virulence factors — molecules that help bacteria invade and colonize potential hosts —  within the TG2G catalog. The researchers warned that around 47% of these virulence factors have never been seen before, and so there is no way of knowing how harmful the bacteria could be."

"Even if these potentially pathogenic bacteria do not survive for long after escaping their glaciers, they can still cause problems, the researchers said. Bacteria have the unique ability to exchange large sections of their DNA, known as mobile genetic elements (MGEs), with other bacteria. So even if the glacial bacteria die shortly after being thawed out, they can still pass on some of their virulence to other bacteria they encounter. This genetic interaction between glacier microbes and modern microorganisms "could be particularly dangerous," the scientists wrote."

"The Tibetan Plateau glaciers could be a hot spot for unleashing future pandemics because they feed fresh water into a number of waterways, including the Yangtze River, the Yellow River and the Ganges River, which supply two of the most populated countries in the world: China and India. Pandemics spread quickly through highly populated areas, as the world witnessed during the COVID-19 pandemic."

"But this potential problem won't just affect Asia. There are more than 20,000 glaciers on Earth covering around 10% of the planet's land mass, and each glacier is likely to have its own unique microbial communities. In April 2021, a study using satellite images of glaciers found that nearly every glacier on Earth showed an accelerated rate of ice loss between 2000 and 2019, which increases the risk that pandemic-spawning microbes could escape anywhere on the planet. The researchers warned that the "potential health risks [of these microbes] need to be evaluated" before they are released from their icy prisons. 

Translation:

It's not a matter of if, but when this occurs.

Covid was just the start.