Sound the alarm on climate change

by Waleed Abdalati

Article Last Updated: 12/18/2008

Environmental scientists who have been watching Earth's climate change dramatically in recent decades recognize an immediate need for comprehensive, coordinated action to address the threats of climate change.

From ground and from space, we see an Arctic in the midst of rapid change: The blanket of sea ice that once covered much of the Arctic Ocean in summer is disappearing. Once-frozen soils are thawing, and buildings, pipelines and forests lean on sinking foundations. Glaciers are disintegrating and ice sheets are shedding massive amounts of ice, feeding already-rising seas.

As predicted for decades, human- caused warming is sweeping across the Earth. This will have impact on water resources, public health, coastal infrastructure, ecosystems and agriculture. No place on the planet will be left untouched.

Leaders in both major parties have given voice to concerns about climate change. Now is the time to act, and swiftly. Climate change is critical to the U.S. economy, national security, international standing, and environmental and cultural heritage. Consider the findings of thousands of scientists around the globe:

• Dwindling sea ice. Since the advent of satellite monitoring in the 1970s, summer Arctic sea ice extent has declined by 39 percent, further amplifying warming and having significant biological, ecological and societal impacts.

• Thawing ground. Across the Arctic, permafrost has warmed up to 13 degrees in the last century — with about half of that increase occurring in the last 25 years. Degrading permafrost releases ancient stored carbon, creating a warming feedback not yet included in most climate models.

• Ice loss in Greenland. Warming has caused a 30 percent increase in melt area of the Greenland ice sheet since 1979, and ice now flows off the sheet much faster than a decade ago.

• Ice loss in Antarctica. Oceanic and atmospheric patterns have protected most of Antarctica from warming. However, the Antarctic Peninsula, which juts into the southern Atlantic, has warmed by about 4 1/2 degrees in the last 50 years. Ice shelves the size of small states have begun disintegrating.

• Rising seas. Oceans are rising because of melting glaciers and ice sheets and because water expands as it warms. Seas have risen twice as quickly in the last 15 years than in the previous 50, and at the current rate of warming, will rise another foot by 2100. However, if warming continues to accelerate and polar ice sheets begin to shrink more rapidly, a rise of 3 feet or much more is possible. That would affect 145 million people around the world, at a cost of nearly $1 trillion, according to the United Nations.

Areas of uncertainty remain, from the roles that air pollution and clouds will play in a warming world to the effect of warmer oceans on hurricanes. But we have enough data today to compel global mitigation, to reduce emissions and lessen the impact of climate change in the future.

Climate change is not an intractable issue. Other harmful global environmental trends have been successfully addressed, most notably the destruction of the ozone layer. We believe such nimble responses are again possible and necessary, to reduce greenhouse gas emissions and prepare communities for change. As before, with great leadership, these actions will create new opportunities for our country to prosper.

We ask President-elect Barack Obama to lead us and the international community — now.

Waleed Abdalati is head of NASA's Cryospheric Sciences Branch at the Goddard Space Flight Center (GSFC) in Greenbelt, Md. Other signers were Walter Meier, Steven Nerem, Mark Serreze, Konrad Steffen, Julienne Stroeve, John Wahr, and Tingjun Zhang, climate scientists and professors at the University of Colorado Boulder. (The opinions expressed do not necessarily reflect the views of CU.)