Just as signs of climate change are becoming clearer throughout the Arctic, scientists are losing some of their ability to keep track of them.
Monitoring stations are closing across northern Canada, Russia, and the United States as governments cut budgets and shift spending priorities. This knocks holes in the networks that record stream flow, precipitation, air temperature, and other climate data.
Satellites with radar and infrared and visible-light sensors can take up some of the slack. "But you really can't do things with remote sensing without on-site observations" to check out what satellites see, says Ted Scambos of the University of Colorado in Boulder.
Dr. Scambos joined fellow climatologists to express their frustration during a meeting of the American Association for the Advancement of Science in Boston.
His Boulder colleague Mark Serreze noted that trends ranging from shrinking sea ice to melting tundra form "a pretty coherent picture of change." It's generally consistent with predictions of global warming as embodied in current computer simulations. But Dr. Serreze explained that the simulations paint a broad-brush view that's hard to match up with the details of specific observations.
Climatologists can play with computer simulations to find a mix of human greenhouse gas emissions and natural factors that lets the computer prediction match real-world climate changes.
Yet, as Serreze observed, "at the very time we're seeing changes, our ability to observe them is degrading."
Without those observations, scientists can't play their computer game.
Serreze led an international project that documented widespread Arctic changes a year and a half ago. He says, "Recent data show more of the same." Surface air temperatures are the warmest they have been in 400 years. Sea ice, glaciers, snow cover, and wind circulation all show changes consistent with global warming predictions.
Claire Parkinson of NASA's Goddard Space Flight Center in Greenbelt, Md., says satellite data from 1979 through 1999 show an average annual loss of Arctic sea ice roughly equivalent to "the combined areas of Maryland and Delaware," according to a paper presented at the meeting.
Serreze's Boulder colleague Mark Meier called attention to the rapid melting of glaciers around the world. He said this has convinced him that sea level very likely will rise substantially higher than the global-warming forecast that the Intergovernmental Panel on Climate Change (IPCC) reported last year.
He explained that the expansion of sea water as it warms is the biggest contributor to sea- level rise. However, the runoff from melting glaciers - exclusive of the vast Antarctic and Greenland ice covers - is a factor that Dr. Meier said even the IPCC underrated.
Runoff is coming from many places; huge glaciers on the Alaskan west coast and in northern Canada are major contributors. Meier said new data from the University of Alaska show they are rapidly wasting away and "currently are contributing about half the rate of global ice loss." Using the new data, he has revised the IPCC forecast that glacier melting could bring 0.16 to 0.36 feet of sea-level rise during this century.
He now expects a rise of 0.65 feet or more. Thermal expansion of water and other processes could add another 0.36 feet or more to bring more than a foot of total sea-level rise by 2100. That could bring a shoreline retreat of 100 feet or more in many places."
Taken together, the trends now seen in the Arctic are a significant indicator of major global climate change that scientists like Meier want to track closely. He joins his colleagues in warning, "There's a lot of monitoring activities that are going down the tubes right now, and we need the data more than ever."