There's a sleeping giant deep in the Arctic tundra: a vast pool of carbon dioxide and methane waiting to be released as global temperatures rise. Releasing those gasses would likely accelerate climate change—a scary thought, once you realize there's more carbon buried in the Arctic than industry and automobiles have released since 1850. But for those who think more in terms of money than floods, droughts, and famine, here's a more concrete statistic: Thawing tundra could cost us trillions of dollars, according to new research.
That bill, by the way, isn't a total cost to be spread out over several decades—it's how much we'd have to set aside today to pay for the damage done by melting frozen soil, or permafrost, in the Arctic, climate researchers Chris Hope and Kevin Schaefer explain today in Nature Climate Change.
Hope and Schaefer computed the expected present cost of melting permafrost—that is, the amount they predict we'd have to save today to offset the economic damage—to be $43 trillion.
"The extra impacts of the permafrost [carbon] and [methane] are sufficiently high to justify urgent action to minimize the scale of the release," Hope and Schaefer write.
At the center of the problem is the fact that soil is one of the planet's richest sources of greenhouse gases—which was completely fine until humans started burning fossil fuels, in the process upsetting the balance of the natural carbon cycle and led to rapid global warming. That warming is also starting to melt permafrost, over time freeing up as much as 1.85 trillion metric tons of carbon—way more than the 350 billion metric tons we humans have spewed into the atmosphere. Even if that happens slowly, it will still be a major contributor to climate change. The question is, in economic terms, how much is it going to cost us?
Hope and Schaefer began addressing that question with Hope's own PAGE09 model, one of several standard integrated assessment models that simultaneously compute global climate change projections and economic impacts associated with agricultural losses, degraded human health, and so on. The researchers incorporated into that a detailed model of carbon flows between the planet's surface and atmosphere, assuming temperature projections given the Intergovernmental Panel on Climate Change's A1B scenario. Slightly less gloomy than the IPCC's current "business as usual" scenario, known as RCP8.5, A1B assumes rapid economic growth, a resulting spread of new, more efficient technologies, and a world population that tops out at around nine billion.
Stringing all those pieces together, Hope and Schaefer computed the expected present cost of melting permafrost—that is, the amount they predict we'd have to save today to offset the economic damage—to be $43 trillion. Uncertainties in the model mean the number could easily be anywhere between $3 and $166 trillion, with the most likely cost around $5 to $10 trillion.
Despite those uncertainties, the results "indicate a need for an abatement strategy that will reduce emissions from thawing permafrost," Hope and Schaefer write. Aggressive mitigation strategies could cut the costs to around $6 trillion, they note—still a big number, but not as bad as it could be.
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