USGS issues Arctic climate change report

People who want to know more about the science of climate change, especially as it pertains to the Arctic regions, might want to take a look at a new report entitled “Past Climate Variability and Change in the Arctic and at High Latitudes,” published by the U.S. Geological Survey. The report is available on the USGS Web site at www.climatescience.gov/Library/sap/sap1-2/final-report/default.htm.

The U.S. Climate Change Science Program commissioned this large and comprehensive document, which has contributions from 37 scientists from the United States, Germany, Canada, the United Kingdom and Denmark.

The report not only provides an overview of the results of climate change research but also places current climate change ideas into the context of the geological record. Geological evidence demonstrates that the Earth’s climate has changed continuously throughout the Earth’s history, while evidence from the more recent geologic past shows how previous temperature fluctuations compare with current climate change, especially in the Arctic.

“By integrating research on the past 65 million years of climate change in the entire circum-Arctic, we have a better understanding on how climate change affects the Arctic and how those effects may impact the whole globe,” said USGS Director Mark Myers when introducing the report on Jan. 16. “This report provides the first comprehensive analysis of the real data we have on past climate conditions in the Arctic, with measurements from ice cores, sediments and other Earth materials that record temperature and other conditions.”Among the findings expressed in the report is a conclusion that current rates and quantities of Arctic sea ice loss are highly unusual compared with what is known to have happened over previous millennia, especially since changes in the Earth’s orbit ought to have lessened the probability of sea ice melting. Sustained warming could result in the eventual disappearance of the Greenland ice sheet and a consequent rise in sea level of several meters.

The report also concludes that there have been rates of Arctic warming in the geologic past comparable to what is being observed at present. However, some projections of future human-induced climate change indicate rates of change exceeding those earlier “natural” rates. The report also warns that human induced climate change could cross a threshold beyond which the change could accelerate to become very fast and very large.

—Alan Bailey