For the first time ever, a group of researchers have laid out the levels of elevation of the ice sheets in Greenland and Antarctica, and the results aren't pretty. The ice sheets are thinning at a remarkably fast rate, the fastest decline in recorded history.
Scientists in a research study laid out the levels of ice on a digital map. The study was led by Dr. Veit Helm, a scientist who studies glaciers at the Alfred Wegener Institute in Bremerhaven, a city in Germany.
"The new elevation maps are snapshots of the current state of the ice sheets. The elevations are very accurate, to just a few metres in height, and cover close to 16 million km2 of the area of the ice sheets. This is 500,000 square kilometres more than any previous elevation model from altimetry", Dr. Helm says.
The scientists constructed these maps using data collected by a CrysoSat-2 altimeter called SIRAL, a satellite-based altimeter that uses radar to scan areas on Earth, and measures the reflection from the glaciers. This data was turned into maps with very fine detail.
Scientists were able to compare the levels of the ice sheets from 2011 to 2014.
"We need to understand where and to which extent the ice thickness across the glaciers has changed. Only then can we can analyze the drivers of these changes and find out how much ice sheets contribute to global sea level rise", Dr. Helm says.
The team used data from more than 200 million SIRAL data points in Antarctica and approximately 14.3 million data points for Greenland, over a period of three years. They found that the ice sheets in Greenland are loosing about 375 cubic kilometers of volume a year, or approximately 90 cubic miles. They found that the rate of thinning in Greenland has at least doubled since 2009, using data collected from the ICESat satellite.
In Antarctica, the rate of thinning has grown three times since 2009. The researchers say that the ice sheets in both regions are thinning at approximately 500 cubic kilometers per year, or approximately 90 cubic miles.
"That is the highest rate observed since altimetry satellite records began about 20 years ago," says Professor Dr. Angelika Humbert, a scientist who studies glaciers at AWI. She was a co-author on the study.
We already know that humans are likely responsible for the melting glaciers, thanks to a research study released earlier in August. What has yet to be determined is how this loss will impact the climate, and what we can do to counteract the effects.
