A great deal has been made in recent years of Greenland’s melting ice sheet. And with reason. The Greenland ice sheet is one continuous block the size of Texas. If it were to all melt, sea levels would rise by 20 feet, enough to flood nearly all of Florida.
No one expects the Greenland ice sheet to melt all at once. More likely, if current climate trends continue, it is a process that will take years. The implications are nonetheless significant. In 2010, approximately 44 percent of the world’s population lived within 90 miles of the sea, according to the United Nations. Even a slight rise in sea levels has the potential to be catastrophic.
Against that backdrop, Neil Humphrey, a professor geology and geophysics at the University of Wyoming, headed to Greenland in 2009. The purpose of the trip was relatively simple: Develop a system to predict how the ice was melting.
If the Greenland ice sheet had the potential to flood cities and entire states, Humphrey reasoned, it would probably be good to accurately predict how the ice will melt.
“There has been a huge amount of theory in the last 10 years ever since people started worrying about Greenland melting,” Humphrey said. “There was no data on what was really happening on and under the ice sheet, so you couldn’t prove or disprove the theories.”
That’s where things start to get complicated. The working theory at the time was one that Humphrey helped develop.
Humphrey, 64, is a glaciologist. He has spent the last three decades studying glaciers in the Himalayas, Greenland, Alaska and Antarctica. The theory that was being used to predict Greenland’s melt was the one developed to predict the melting of mountain glaciers.
But there was a problem. Mountains are steep, obviously enough. In a mountain glacier, the melting water gains momentum as it moves downhill, forming river-like streams beneath the glacier’s surface.
Greenland, on the other hand, is flat. The distinction is important. It could mean the difference between the ice melting faster or slower, thereby raising sea levels faster or slower.
Humphrey suspected the ice there was melting differently. With Joel Harper, an associate professor at the University of Montana, and a team of 10 to 12 others, Humphrey developed a drill to bore down to the base of the ice. The team then installed sensors to document how the ice was melting.
“It turns out the water is not flowing in rivers,” he said. “It is flowing in very distributed, small, little channels; hundreds of thousands of little channels.”
The implications are widespread. The data is still being analyzed, but Humphrey suspects that Greenland’s ice is melting at a slower rate than previously thought. It also calls the previous theory on how Greenland’s ice is melting into serious question.
Humphrey and his team published their findings in this month's edition of the journal Science.
But what does it all mean? Can Florida celebrate or has the Sunshine state’s execution merely been stayed? It’s a complicated question, not the least because of the political debate surrounding global warming. Humphrey’s research, like that of many scientists, does not fit into the neatly constructed boxes employed by politicians on either side.
Take the melting of Greenland’s ice sheet. Each summer, about 10 feet of Greenland’s ice melts and each winter the ice is replaced. The alarm bells begin ringing when the melt exceeds 10 feet. Humphrey believes the alarm bells are just starting to sound.
“Despite the fact that Greenland is melting quite dramatically right now, it is not impacting sea level rise. That is the melting mountain glaciers,” he said, noting the dramatic retreat of glaciers in places like the Wind River Mountains, Glacier National Park, and Alaska. “Greenland will kick in another 10 to 20 years.”
Humphrey worries about the hubbub around Greenland’s ice sheet. If the melting ice sheets are not contributing to sea level right now, but a huge deal is being made of their melting, the public might lose interest. They’re not contributing to the problem now, so what’s the big deal?
And that, Humphrey believes, is dangerous. For low-lying states and countries, the stakes are huge. Places like Bangladesh, the Netherlands and Denmark could all be flooded, forcing their populations to seek higher ground elsewhere.
“Sea level rise is hugely problematic human concern in the next 20 to 30 years,” Humphrey said. “The political disruption that will be caused by sea level rise rivals things like the Great Depression and the dust bowls.”