By Charlene Porter,
iip Staff Writer
February 9, 2012
Satellite observations accumulated over a seven-year period show that the volume of Earth’s land ice mass decreased by 4.3 trillion tons (more than 4,150 cubic kilometers) and increased global sea level by 12 millimeters.
That’s enough ice to cover the entire United States to a half-meter depth.
A research team at the University of Colorado reached these conclusions based on satellite measurements collected from 2003 to 2010 by the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE).
“Earth is losing a huge amount of ice to the ocean annually, and these new results will help us answer important questions in terms of both sea rise and how the planet’s cold regions are responding to global change,” said University of Colorado–Boulder physics professor John Wahr, who helped lead the study.
Greenland and Antarctica, the planet’s two greatest ice masses, account for roughly 75 percent of Earth’s total land ice. Because of their size, they have been the focus of previous research, and decreases in their size have been documented. The more difficult scientific task has been to assess the changing sizes of some 200,000 smaller glaciers around the planet in the Himalayas, the Alps and the Andes, for example.
Previously, these ice masses have been measured with ground-based methods, and those findings have been used as the basis for inferences of the expansion or contraction of an entire glacier. The data used in this analysis —collected by dual satellites of the Gravity Recovery and Climate Experiment — show that the traditional methods produced inaccurate results.
Earlier estimates calculated that the high Central Asian mountains — the Himalaya, the Pamir and the Tien Shan — were losing up to 50 billion tons of ice annually. The GRACE measurements revealed a loss of only 4 billion tons annually. One possible explanation for the discrepancy, the University of Colorado team reports, may be that estimates based on ice loss measurements at the bottom of the glacier did not take into account the much colder temperatures at greater elevations up the mountains.
“The results sharpen our view of land ice melting, which poses the biggest, most threatening factor in future sea level rise,” said Tom Wagner, cryosphere program scientist at NASA headquarters in Washington.
EMERGENCY RESPONSE IN THE ARCTIC
Melting ice is opening new channels through Arctic waters. This is expected to lead to greater shipping traffic and greater risks of accidents that could spill oil or other toxins into the region’s waters. U.S. maritime agencies are preparing with better tools to mount a speedy response to accidents, minimize damage and contain environmental impact.
By this summer, a new mapping tool, first used in the 2010 oil spill in the Gulf of Mexico, will be available to federal responders in the Arctic. The Environmental Response Management Application (ERMA®) pulls together and processes real-time and static data in a single interactive map, providing a clear visualization of the overall situation and improving communication and coordination among responders trying to control and contain the problem.
The National Oceanic and Atmospheric Administration (NOAA) and the Bureau of Safety and Environmental Enforcement in the Department of the Interior are working together to modify the tool for use in the Arctic.
“Launching this tool for responders, media and the public during the Deepwater Horizon oil spill was a groundbreaking technical achievement and one of the most significant contributions NOAA provided to the historic, large-scale response,” said NOAA Under Secretary Monica Medina.
With this action, the United States is working toward a goal adopted by the Arctic Council to increase response capabilities in the event of an environmental accident. The United States is one of eight member states in the Arctic Council, committed to limiting and reducing emissions of pollutants into the region’s environment.
The other Arctic States are Canada, Denmark (including Greenland and the Faroe Islands), Finland, Iceland, Norway, Russia, and Sweden. Six international organizations representing Arctic indigenous peoples also have permanent participant status.
SCIENCE-BASED DECISIONMAKING IN THE ARCTIC
Obama administration officials February 7 reaffirmed their commitment to base energy-related decisions in the Arctic on the best available science. Representatives of the White House and the Department of the Interior were in Anchorage, Alaska, to announce the ERMA® initiative and other mechanisms to draw the most accurate and timely information from the energy industry and research scientists as development decisions are weighed.
The announcements “demonstrate that collecting, synthesizing and delivering relevant information to decisionmakers is a top priority for this administration,” said Deputy Secretary of the Interior David Hayes in remarks to the Alaska Forum on the Environment.