New study reveals the true cost of Earth's melting permafrost

The science behind the melting Arctic permafrost, is, frankly, terrifying. As it melts, mummified remains of animals are slowly emerging, offering us a glimpse at the ancient world — one that scientists believed would always remain hidden, locked up for good. These puppies, birds, and other fauna are the proverbial canaries in the coal mine.

Now, a new study published Thursday in Scientific Reports gives us even more cause for concern.

Jørgen Randers is one of the study's authors and professor emeritus of climate strategy at the BI Norwegian Business School. He tells Inverse that the permafrost may not just be melting — it might never freeze again.

"According to our system dynamics simulation model ESCIMO, humanity is beyond the point-of-no-return when it comes to halt the melting of the permafrost using greenhouse gas cuts as the single tool," Randers says.

In other words: cutting down on (or completely eliminating) greenhouse gas emissions now won't stop the melting of the permafrost in the future.

Instead, Randers explains, it "will continue to melt over the next 500 years — irrespective of how quickly humanity cuts its greenhouse gas emissions."

How did we get here — To come to this dire conclusion, Randers and co-author Ulrich Goluke used a simulation model known as ESCIMO (an Earth System Model of Intermediate Complexity) to observe the self-sustained melting of the permafrost. Goluke is assistant professor at the Business School Lausanne, Switzerland.

They look at two possible scenarios.

In the far more likely of the two scenarios, they assume that humans completely eliminate manmade greenhouse gas emissions by 2100. Under this scenario, global temperatures reach a peak around 2075 before falling for 75 years to 2 degrees Celsius above temperatures in a pre-industrial Earth by 2150. That's in tune with other science on what such a drastic action would have on global warming.

What is unexpected is everything that happens after 2150. After 2150, the global temperature counterintuitively starts rising again, despite no new production of greenhouse gases.

In the highly unrealistic second scenario, which posits that humanity abruptly cuts all greenhouse gases in 2020, the same pattern of initial decline followed by global warming still occurs.

Essentially, we've missed the boat. Rather, to stop the melting of the permafrost now, the study states that "all man-made emissions would have had to be cut to zero sometime between 1960 and 1970" — when the global temperature was only 0.5 degrees Celsius above pre-industrial levels.

Vicious cycle — This bizarre oscillation in global temperature comes down to three factors: the melting of the permafrost itself, increased water vapor, and decreasing surface albedo.

These three processes interact in a self-sustaining feedback loop, resulting in more carbon (in the form of methane or CO2) being released into the atmosphere. More carbon increases global temperatures and causes even more melting of the permafrost.

Let's focus on that last factor: surface albedo.

"Surface albedo is the same as the reflectivity, shininess of the Earth's surface as seen from space. Bright surfaces like snow and ice reflects most of the incoming energy from the Sun," Randers says.

By contrast, dark areas — like the sea — reflect less and instead absorb more energy.

"This means that as the globe warms, the area covered by ice and snow diminishes, laying bare ever more ocean surface, which absorbs more of the incoming light, warming and melting even more surface ice," Randers says.

This has extreme implications for humans over the next 200 years — from 2150 on, the global temperature will continue to rise 0.5 degrees Celsius every century, according to Randers.

"The rise will be so slow that humanity will probably adapt," Randers says — but he cautions that we will also suffer worse than if the temperatures and sea levels did not rise.

What's next for the permafrost — Cutting greenhouse gases in the next fifty years is still important for the survival of our species, and our actions now do influence temperature increases in the future. But we also need to innovate our way out, too.

"The world should accelerate its effort to cut greenhouse gas emissions and start developing the technologies for large scale removal of greenhouse gases from the atmosphere," Randers says.

Eliminating greenhouse gases may not save the permafrost in the long run. But investing in other innovative technologies, like carbon capture, could go a long way, Randers suggests.

It's also worth keeping in mind that this is only one simulation, and other models may yield more fruitful information about how to save the permafrost from melting.

"The next — and most urgent — step is for other model builders to investigate whether they see the same phenomenon (sustained melting of the permafrost) in their models," Randers says. "Their models are much bigger than ours, and may reveal counteracting forces that can stop the melting we observe in ESCIMO."

Abstract: The risk of points‑of‑no‑return, which, once surpassed lock the world into new dynamics, have been discussed for decades. Recently, there have been warnings that some of these tipping points are coming closer and are too dangerous to be disregarded. In this paper we report that in the ESCIMO climate model the world is already past a point‑of ‑no‑return for global warming. In ESCIMO we observe self‑sustained melting of the permafrost for hundreds of years, even if global society stops all emissions of man‑made GHGs immediately. We encourage other model builders to explore our discovery in their (bigger) models, and report on their findings. The melting (in ESCIMO) is the result of a continuing self‑sustained rise in the global temperature. This warming is the combined effect of three physical processes: (1) declining surface albedo (driven by melting of the Arctic ice cover), (2) increasing amounts of water vapour in the atmosphere (driven by higher temperatures), and (3) changes in the concentrations of the GHG in the atmosphere (driven by the absorption of CO2 in biomass and oceans, and emission of carbon (CH4 and CO2) from melting permafrost). This self‑sustained, in the sense of no further GHG emissions, melting process (in ESCIMO) is a causally determined, physical process that evolves over time. It starts with the man‑made warming up to the 1950s, leading to a rise in the amount of water vapour in the atmosphere—further lifting the temperature, causing increasing release of carbon from melting permafrost, and simultaneously a decline in the surface albedo as the ice and snow covers melts. To stop the self‑sustained warming in ESCIMO, enormous amounts of CO2 have to be extracted from the atmosphere.