Melting Permafrost Reveals Cute Ice-Age Animals — and Climate Challenges?

As ice-age creatures resurface from the frost, scientists grapple with the climate risks of thawing permafrost

Do you think that global warming is just melting ice caps and glaciers? Well, think again! It’s also thawing permafrost in the Northern Hemisphere.

You may have noticed that, recently, the news talks a lot about animals that lived during the ice age who, after dying, got preserved in the ice for thousands of years. This is because paleontologists have been finding a lot more of these animals in recent years.

And while, as a paleontologist, I’m excited to learn that these now-extinct animals are being found, helping us better understand life on our planet, I’m a bit worried. Talking to my peers, I can see that they are, too.

There’s a reason we are finding more of these specimens locked up for years, and it’s not that our paleontological fieldwork technologies have advanced dramatically overnight.

As the Arctic warms, permafrost, the frozen ground that blankets much of the Northern Hemisphere, has begun to thaw. The issue is that this process exposes enormous amounts of soil organic carbon (SOC) that have been locked away for millennia.

This frozen ground poses a tricky question: how much of this carbon will escape into the atmosphere, and what will that mean for our climate?

A recent study led by Dr. Lei Liu and his team tackles this issue, exploring how permafrost thaw might impact the carbon cycle through the 21st century.

Their findings paint a picture of significant, but not catastrophic, carbon release. However, this comes with some caveats.

But first of all, let’s look at why thawing permafrost matters.

Permafrost acts like a giant freezer, preserving organic matter that never fully decomposed. However, when it thaws, this carbon becomes vulnerable to microbial decomposition, releasing greenhouse gases like carbon dioxide (CO2) and methane (CH4) into the atmosphere. These emissions create a feedback loop: warming thaws more permafrost, which releases more carbon, fueling further warming.

However, not all stored carbon is released into the atmosphere after thaw. In fact, most of the newly exposed carbon stays in the soil, especially in deep layers, thanks to several factors. Decomposition slows in deeper soils due to low microbial activity, reduced oxygen availability, and physical barriers like soil aggregates.

To better understand these processes and what they could mean to the future of our planet, the team employed a process-based biogeochemical model, which is just a fancy way of saying they combined real-world data with detailed computer simulations to track what happens as permafrost thaws. What sets their work apart from other previous studies, though, is the inclusion of deep-soil processes up to six meters below the surface, double the depth of many earlier studies.

They also incorporated observational data on soil organic carbon, ensuring their model reflected real conditions as closely as possible. Using two scenarios: 1) optimistic (limiting global warming to 2°C) and 2) grim, a business-as-usual path where we keep warming our planet, they explored whether carbon would move from frozen soil into the atmosphere or remain trapped underground.

And what did they find?

Let’s start with the numbers. Under the optimistic scenario, 119 gigatons (Gt) of carbon will thaw by 2100, while the business-as-usual scenario could unleash 252 Gt. To put that into perspective, humans currently emit about 11.3 Gt of carbon annually, so that’s 10 to 20 times what we emit annually.

However, despite these large numbers, only 4–8% of the thawed carbon is expected to make its way into the atmosphere this century. That’s roughly 10–20 Gt, or approximately what we emit each year, depending on how much we let the planet heat up.

For now, though, the majority of thawed carbon will stay locked in deep soil layers, where cold temperatures and limited microbial activity slow decomposition.

On the other hand, hawing permafrost doesn’t just release carbon; it also makes nitrogen more available. This nutrient boost can promote plant growth, which in turn absorbs some atmospheric CO2. In theory, this should offset some carbon losses. However, the reality is less straightforward.

Much of the released nitrogen remains out of reach for plants because it’s locked in deep soil layers or becomes available during the wrong seasons. Additionally, even where plants can access it, their carbon uptake only partially compensates for the carbon lost from thawed permafrost.

For instance, in the most optimistic scenario, increased vegetation absorbs just a fraction of the carbon released into the atmosphere. In the study, vegetation gained an extra 0.4 to 1.6 Gt of carbon, depending on the scenario.

However, while plant growth would help, it does not outweigh the carbon loss from thawed permafrost. Thawing permafrost can boost vegetation growth in some areas, but it also alters plant species composition and soil structure. Thus, the process exposes ecosystems to new risks, like soil erosion and changes in hydrology, further complicating predictions.

Here’s the problem: as warming continues, processes like abrupt thaw, deeper root growth, or changes in microbial communities could speed up carbon release. That’s where things could get messy; even if paleontologists are happy to find yet another ice-age animal, we need a functional planet to study those.

Moreover, abrupt thaw events like thermokarst, where ground ice melts suddenly, can accelerate carbon release. However, these processes, along with microbial colonization and root deepening, are not yet fully accounted for in many climate models. This means current estimates of permafrost carbon emissions could be conservative, and that more research needs to be done.

The Arctic and other high-latitude regions, warming nearly four times faster than the global average, remain at the forefront of these changes. “Most thawed permafrost carbon will stay sequestered in previously frozen layers this century,” said the study authors, highlighting a temporary relief.

But as long as warming continues, the potential for accelerated carbon release continues to threaten the planet.

You may be thinking, though, why does this matter?

Well, this study adds important information to our understanding of permafrost and its role in climate change. Everybody talks about the consequences of the thawing permafrost, but we’ve never seen estimates for how much carbon we’re talking about.

This research gives us a clearer picture of how much carbon we’re really talking about and, more importantly, when it might become a problem.

And what do we see? Well, while it’s not a doomsday scenario, it’s a warning shot. If we continue on a high-emissions path, the feedback loop between warming and permafrost carbon release could become a bigger challenge for future generations. So we better understand what’s going on now.

While the study projects that most thawed carbon will stay buried this century, it emphasizes the importance of understanding and mitigating permafrost’s long-term effects.

The fact that deep soil carbon decomposes more slowly doesn’t eliminate the problem; it simply delays it. As warming continues, even small increases in emissions from thawing permafrost could compound the challenges of meeting global climate targets.

This research highlights the need for advanced models that incorporate the complex interactions between soil, microbes, plants, and climate. By refining these tools, scientists can better predict the timing and magnitude of permafrost’s impact on the carbon cycle.

Is there anything we can do though?

Well, the best way to manage the risks of thawing permafrost is to reduce global greenhouse gas emissions. Limiting warming to 2°C could drastically cut the amount of carbon released from permafrost, buying time to adapt and respond. Additionally, preserving Arctic ecosystems through sustainable land management can help maintain the region’s natural carbon sinks.

Thawing permafrost is a reminder of the complex connections between climate systems and ecosystems. While it’s not the most immediate threat, it’s a ticking clock that will keep scientists (and hopefully policymakers) on their toes for decades to come.

The takeaway?

Reducing global emissions now could buy us valuable time. Limiting warming to 2°C drastically cuts the amount of carbon released from permafrost, keeping the situation more manageable until we find better solutions that can be applied globally.

It’s another reason why climate action matters. It’s not just about polar bears or glaciers; our atmosphere and future could depend on them. Paleontologists can dig in a dying planet just like you wouldn’t be able to perform your job, either.