Portal to feature daily updates on melting episodes and analysis of conditions
By Bob Berwyn
SUMMIT COUNTY — Climate scientists have long been keeping a close watch on Greenland’s ice sheet, a key indicator of global warming impacts. This month, the National Snow and Ice Data Center launched a new website to help track the changes on an continual basis.
The new site, Greenland Today, will present images of the widespread melt on Greenland during 2012 and scientific commentary on the year’s record-breaking melt extent, which far exceeded all previous years of satellite monitoring, and led to significant amounts of ice loss for the year.
Satellite images updated daily, with a one-day lag and a daily melt image shows where the surface of the Greenland Ice Sheet experienced melt on that day.
“The Greenland melting last year was just tremendous … about 600 to 700 billion tons of ice melted and ran off,” said NSIDC glaciologist Ted Scambos, explaining that, as recently as the 1990s, scientists estimated the rate of melt at anywhere from zero to 30 billion tons. Just in the past few years, that number jumped dramatically, from 100 billion to 500 billion tons or more, Scambos said.
“It’s very sobering. We’re just at the beginning of the climate change era, and we’re likely to see two to three times the rate of warming we’re seeing now,” said Scambos, who has recently been involved in field research on the Larsen Ice Shelf in Antarctica. He also completed a traverse from Troll Station near the Dronning Maud Land coast in Antarctica to the South Pole as part of the Norwegian-American Scientific Traverse of East Antarctica.
Evidence of past Greenland heat waves similar to the 2012 event have been found in ice core records, but hadn’t been observed in the satellite record, but all the largest melting events have been in just the past 10 years
Scientists and interested citizens will be able to use the website to monitor how high up and how close to the center of the Greenland ice sheet the melting extends each summer. One of the big questions is whether the 2012 melting episode was a meteorological fluke or if it will be repeated more often in coming years.
Data compiled on the website will help scientists understand how sensitive snow and ice areas are to warming and to measure the total mass loss from the ice sheet — a key factor for calculating sea level rise.
“So if we’re seeing more mlting, is it leading to an increased flow rate off the surface?” he said, explaining that, as surface water seeps down through cold ice it remains liquid, and can slicken the bed of the glaciers. allowing them to slide out more rapidly.
Scientists have been able to measure a period of glacial acceleration in mid-summer to early autumn. So far, it hasn’t been a net contributor to mass loss, but that could change in the future, Scambos concluded.
“Everything points to an acceleration. It’s a huge system, so responses can be very delayed … we’re now we see more sensitivity to surface temperatures,” said Marco Tedesco, an atmospheric and earth scientist at City University of New York who has been tracking surface melting on Greenland for years. Track his research at greenlandmelting.com.
“Greenland has been setting melting records the past 5 years. The new points on the time series will give us more information … I think what we can say is that, we don’t expect slowing,” Tedesco said.
“We know temperatures are going to increase, with warmer winter and spring weather increasing the length of the melting season … all these different mechanisms are nonlinear but combine to amplify the overall melting … they all point to continued acceleration,” he said.
Tedesco said the new website will help meet the interest and demand for more information, given the recent records and trends.
“It’s going to help to bring Greenland’s evolution to the public. We take for granted this type of technology; data collected and processed within a few hours to see where and how long it’s melting,” he said, explaining how the new website will offer updates nearly in real time.
The site was developed by NSIDC scientists at the University of Colorado Boulder with partial support from NASA, and with data from Thomas Mote of the University of Georgia.