Greenland is melting at an historically unprecedented rate

If it all melted, Greenland’s ice would raise sea level by seven meters.

Greenland was losing ice four times faster in 2012 than it was in 2003, new research has found. The study's lead author, Michael Bevis, says global warming is to blame. We spoke to Bevis, a professor of geodynamics at The Ohio State University, about his research and what it means.

ResearchGate: What motivated this study?                 

Michael Bevis: The loss of ice mass to the oceans is the second largest contributor to sea level rise. Greenland has been losing ice mass faster than Antarctica in the last few decades, so any major acceleration will lead to a significant acceleration in sea level rise.

RG: Can you tell us briefly what you discovered?

Bevis: A lot of recent focus has been on increasing rates of glacial discharge, often driven by ocean warming. However, what we discovered was that most of the acceleration in ice loss since 2003 was focused in southwest Greenland, an area with very few major outlet glaciers. What accelerated in this region was the runoff of summertime meltwater.

We also found this enhanced melting correlated with a natural cycle in atmospheric circulation and weather conditions called the North Atlantic Oscillation (NAO). But the NAO has been happening for thousands of years, so why has such transient warming produced a major increase in summertime melting only since 2002? Because it is superimposed on more steady and progressive global warming of the atmosphere. The NAO and global warming have been working together to produce historically unprecedented amounts of melting. As global warming continues, the situation will get worse.

“As global warming continues, the situation will get worse.”


RG: Just how much ice does Greenland have? What percentage has been lost?

Bevis: Greenland has enough ice to raise sea level by seven meters if all the ice melted. Only a very small percentage has been lost in the last few decades, but the big worry is that the rate of ice loss in Greenland and Antarctica is accelerating, and the rate of sea level rise is accelerating. If the sea level rose even by 0.5 meters relative to sea level at the turn of the century, this would cause catastrophic damage near coastlines all over the world.

RG: How is global warming causing Greenland’s ice to melt faster?

Bevis: Global warming has two faces: global ocean warming and global warming of the atmosphere. Global ocean warming encourages outlet glaciers to stream more icebergs into the ocean. Global warming of the atmosphere increases the rate at which ice is lost in the form of meltwater running into the oceans.

RG: What kind of consequences will this melting ice have?

Bevis: Continued global warming will damage humanity, animal and plant life, and the global economy in many different ways. Rising sea levels, more extreme weather events, flooding, drought, agricultural collapse, mass migrations of animals and people, out-of-control wildfires, toxic algae blooms in our lakes and rivers, massive loss of biodiversity, collapse of our coral reef systems and our fishing resources, etc.

The warming of Greenland, the accelerating loss of sea ice near Greenland, and the accelerating loss of ice mass in Greenland will certainly prove very damaging to its existing ecosystems. In terms of its global impacts, probably the most important will be Greenland's increased contribution to sea level rise.

RG: Can this increasing rate be slowed or stopped

Bevis: Greenland hit a tipping point in turns of its melting behavior near the beginning of this century, and it is now extremely unlikely that summertime melting can return to pre-2000 levels. Humanity's main focus now has to be to mitigate future warming so as to prevent major future accelerations in ice loss. The warmer the summers get; the more melting will occur. Eventually the melting could do more than raise sea level, it could even start to modify the global ocean circulation system. Significant damage is now unavoidable. The goal of mitigating global warming is to prevent the damage levels increasing from serious to catastrophic.

RG: What’s next for your research?

Bevis: I plan to use data from the follow-on GRACE satellite mission, the Greenland GPS Network (GNET) and regional climate modeling systems like MAR and RACMO2 to study the space-time structure of accelerations in ice loss, so as to be able to make more informed projections of what will happen in the next 20 to 30 years.

“The notion that we must choose between saving our climate system and saving our economy is absurd. Climate change is the single biggest threat to our economy.”


RG: Do you have any advice for policy makers?

Bevis: Science is an endlessly self-correcting process that pursues a better understanding of all aspects of nature. In essence, science is apolitical. It pursues the truth. It is tested by its ability to make accurate predictions. Think about how well weather predictions have improved in the last forty years. That is the march of science. As a citizen and as a scientist, I offer the following observation. The general population and especially the political classes need to take the warnings of the scientific community far more seriously. Since modern, well-funded, professional science emerged after World War II, there is not a single example of a nearly unanimous scientific consensus involving thousands of scientists being wrong. Think of smoking and lung cancer, acid rain, the ozone hole, etc. The scientific community was right then, and it is right now about global warming. The notion that we must choose between saving our climate system and saving our economy is absurd. Climate change is the single biggest threat to our economy, and to the well-being of our children and of all future generations.

Featured image courtesy of Daniel Carlson. Find more images on his project here.
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