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Greenhouse Gases Up in 2010; Glacial Melt Study Begins

By Charlene Porter

Staff Writer

Washington - An annual survey of greenhouse gases in the atmosphere and their influence on climate shows a steadily upward trend, the National Oceanic and Atmospheric Administration (NOAA) said November 9.

The Annual Greenhouse Gas Index (AGGI) climbed to 1.29 in 2010, which means that "the combined heating effect of long-lived greenhouse gases added to the atmosphere by human activities has increased by 29 percent since 1990," according to a NOAA press release. The year 1990 serves as the "index" year, that is, the starting line to which successive years are compared. The 2010 finding is up slightly from a 1.27 index calculated in 2009.

"The increasing amounts of long-lived greenhouse gases in our atmosphere indicate that climate change is an issue society will be dealing with for a long time," said Jim Butler, director of the Global Monitoring Division of NOAA's Earth System Research Laboratory.

The AGGI is calculated each year based on atmospheric data collected through an international cooperative air sampling network that monitors more than 100 sites around the world.

Scientists from many countries are working collaboratively to understand climate change and the many effects it could have on the Earth and human activities, including on water supplies, agriculture, ecosystems and economies.

A rise in global sea levels is another consequence of a warming climate, a matter of urgent concern to low-lying regions and island nations. The Intergovernmental Panel on Climate Change (IPCC) has calculated that world sea levels rose at an average rate of about 3.1 millimeters per year from 1993 to 2003.The IPCC, established by the United Nations more than 20 years ago, is an intergovernmental scientific body, conducting ongoing assessments of data on climate change.

One glacier in a remote area of Antarctica is melting fast, and could contribute significantly to global sea-level rise if it continues. An international team of researchers backed by NASA and the National Science Foundation will be on the way there soon to spend six weeks on an ice shelf of the Pine Island Glacier to determine how changes in the waters circulating underneath are causing accelerated melting.

According to a press release from NASA's Goddard Space Flight Center, satellite measurements show a decline in the ice cover and raise the possibility that the glacier could flow out to sea in the future. The scientists will use a number of different methods to measure the shape of the cavity underneath the ice shelf and determine how warmer ocean waters flow into that space and cause melting from the base of the glacier.

The warmer, salty waters and fresh glacier melt create a rapidly rising water stream, causing more melting as the stream moves out toward the open ocean.

"The Pine Island Glacier ice shelf continues to be the place where the action is taking place in Antarctica," said Robert Bindschadler, who is leading the expedition. "It can only be understood by making direct measurements, which is hard to do."

Bindschadler, glaciologist emeritus at Goddard, first proposed this expedition five years ago, and in 2008 became the first person to walk on the Pine Island Glacier. Pursuing this science now is "even more urgent" than when it was first envisioned, he says.

"This could have a significant impact on global sea-level rise over the coming century," said Scott Borg, the director of the Division of Antarctic Sciences at the National Science Foundation, the group that coordinates all U.S. research on the planet's coldest, driest continent.

The team will use a hot water drill to bore down through the ice shelf. Then the team will send a camera down into the hole the team drilled to observe the underside of the ice shelf and the sea floor. Another instrument will move up and down through the hole and the water beneath the glacier, taking measurements of temperature, salinity and the water currents. With other instruments, the team will also measure the exchange of heat between ice and water and the speed of heat transmission through the ice.

The team of 13 scientists begins its mission in December.

(This is a product of the Bureau of International Information Programs, U.S. Department of State.)