Photo: Bryan Kiechle/Flickr
In a region of Antarctica where we assumed the permafrost was stable, new research published in Nature shows that the balance of seasonal melting and freezing has been upended in the past decade, with melting accelerating so that it's comparable to the Arctic.
Scientists from the University of Texas, looking at the Garwood Valley–one of the southern McMurdo Dry Valleys of Antarctica–have found that the rate of permafrost melting there is now 10 times the historic rate documented for the entire present geological era—a "dramatic shift from recent history," according to report lead author Joseph Levy.
Image: University of Texas
The researchers chalk the thaw up to climate change. Even though the Dry Valleys have relatively stable temperatures, the amount of sunlight reaching them has increased due to changing weather patterns. Under the sunnier weather, the ground in the region—which isn't covered by the vast ice sheets on the surface of the ground you probably picture in Antarctica; here the ice is buried under sediment—absorbs more solar radiation. This is "effectively cooking the nearby ice and accelerating melt rates."
Though the melting is quite dramatic—this ice dates back to the last Ice Age; today the region is entirely a desert—and likely to continue as temperatures continue to rise while the global climate changes, the McMurdo Dry Valleys comprise less than one-third of a percent of the total Antarctic land mass.
As opposed to the potentially catastrophic bump in greenhouse gas emissions that could result if Arctic permafrost quickly melts, scientists here are presenting their findings as more of an interesting geologic curiosity. As the ground continues to thaw, researcher believe the landscape will sink and buckle, creating retrogressive thaw slumps.
Furthermore, unlike other ice melting in Antarctica which can contribute significantly to sea-level rise depending upon whether its already floating on the water or resting on solid ground, the ground ice melting here isn't really a major component of the frozen water on the continent.
Which is all to say: we're talking about an amazing effect of rising greenhouse gas emissions and temperatures that elsewhere—let it sink in again that the ice in the McMurdo Dry Valleys has been there since the last Ice Age, as in, before all recorded human history—both of which are leading us to some definitely detrimental-to-civilization ice melting on the rest of the continent.
So far, Antarctic ice melt is responsible for less than 10 percent of global sea level rise. Over the coming centuries though, as climate change locks in multi-meter sea level rise, recent research shows that melting the massive Antarctic ice sheets will account for over 50 percent of sea level rise. Residents of Boston, Miami and New York who might scouting dry valleys of their own, take note; there's some sunny ones down south.