Hey, we haven’t checked in Greenland in a while, let’s see what happens … Oh. Oh no.
New research published on Wednesday in Nature shows that the Greenland ice sheet has already exceeded the limits of mass loss for the past 12,000 years. Even under the best climate scenario, in which humankind is now cutting emissions as quickly as possible, the ice sheet will suffer unprecedented losses over the course of the century.
The Greenland ice sheet has been really battered in recent years. Wildfire smoke, dust, and heat waves even sunny skies have all contributed to massive annual breakdowns. It’s losing ice faster, and the new study adds those losses from the previous year and puts them in the context of the past and the future. To do this, the researchers used computer simulations from the past and then compared them to ice core samples and other data based on the geology in Greenland. These geological and ice core proxies enabled researchers to reconstruct the growth and loss of ice over the past 12,000 years for an area in western Greenland that mirrors the rest of the ice sheet. The time frame is significant as it represents the end of the Ice Age and a time known as the Holocene.
During this time, natural climatic fluctuations have affected the ice sheet, including a major loss period some 8,000 years ago when an estimated 6,000 gigatons of ice melted in the ocean every century. That’s 6 trillion tons of ice that I could compare, but let’s just call it a load of ice. Since then there have been much smaller disruptions in the ice sheet. Until now, that is.
Humans have started to overwhelm this system by pumping carbon pollution into the atmosphere. The planet has warmed about 1 degree Celsius since the late 19th century, but warming has increased in recent decades. This created all sorts of problems, including a more rapid decline in the mass of the Greenland ice sheet. The new evidence suggests that Greenland would shed 6,100 gigatons of ice, or a little more than a load, if the rate of loss remained the same over the past two decades during this century.
Unfortunately, climate change has other plans. Future modeling of the study shows that an extremely optimistic climate scenario in which the world is currently starting to reduce emissions and zeroing them by the end of the century would still result in a minimum of 8,800 gigatons of ice this century. If the world goes wild and this century continues to burn carbon with reckless abandon, up to 35,900 gigatons (nearly 6 assloads) of ice could end up in the ocean. In one cheerfully titled comment Fairbanks ice researcher Andy Aschwanden, who accompanies the University of Alaska piece “The Worst Is Yet to Come for the Greenland Ice Sheet”, notes that “it is becoming increasingly certain that we will see unprecedented rates of ice loss in Greenland”.
This has a huge impact on coastal communities and ecosystems. The melting ice sheet is responsible for about 30% of the total rise in sea level, and its contribution will increase on the increasingly unstable ice in Antarctica this century. The results show that regardless of the measures humankind takes to curb emissions, countries must also adapt to a world with higher seas. That could mean expanding natural or artificial flood protection or Retreat from the coast a total of.
At the same time, all of the ice melt from Greenland is leading to a pocket of colder, fresher water off the coast. This slows down the current that goes up the east coast and from there to the other side of the Atlantic. How this affects the local ecosystem as well as the circulation of the oceans in other countries is still an area of active but troubling research. Scientists will continue to study the fate of the ice sheet itself under different emission scenarios, and I just want to point out that world leaders should work to ensure that we don’t get a chance to review their work in the high-end one .