4.2
Thawing permafrost and human health

Did you know?
Life is slow in the cold. That is why we put food in the fridge and freezer to slow down the activity of bacteria and fungi that would otherwise decompose the food.
However, old viruses and bacteria that cause diseases can survive for a long time in permafrost. Some simple forms of life are still viable after being preserved in permafrost for hundreds of thousands of years. This is interesting to scientists working in space who would like to look for simple life preserved in very old permafrost on other planets such as Mars.
Thawing of permafrost in ancient soils can stimulate the activities of microorganisms that release large amounts of carbon dioxide from dry areas and methane from wet areas. These green-house gases increase the rate of global warming with potential harm to millions of people through sea level rise etc.
Locally, permafrost is used in the mining industry to contain polluted waters called "tailings". When the permafrost thaws, the tailings are released to pollute wider areas.
Permafrost thaw often results in ground subsidence that damages buildings, roads and railways etc. that are not designed for this eventuality.
Explosions in permafrost areas (see story 4.6) could be harmful for example breaking oil pipelines and leading to pollution. However, so far no harm has been found.