Global warming manifests in documented Arctic changes

New Arctic report card documents ongoing climate change impacts

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Temperatures across the globes high northern latitudes during the first decade of the 21st century were well above the 1971 to 2000 average. Graphic courtesy NOAA.

By Summit Voice

SUMMIT COUNTY — Along with the widely reported weather extremes that affected the mid-latitudes were most people live, the remote Arctic also continued to show the effects of climate change in 2012.

Steadily rising global temperatures manifested in the lowest sea ice extent on record in mid-September, dropping nearly 20 percent lower than the previous record set in 2007; the Greenland ice saw a rare widespread melting event and the northern hemisphere snow cover extent also dropped to record low during the spring, according to NOAA’s Arctic Report Card.

“The Arctic is changing in both predictable and unpredictable ways, so we must expect surprises,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator, during a press briefing at the American Geophysical Union annual meeting in San Francisco, Calif. “The Arctic is an extremely sensitive part of the world and with the warming scientists have observed, we see the results with less snow and sea ice, greater ice sheet melt and changing vegetation.”

More than 100 researchers contributed to the report documenting the changes in the Arctic, including an increased length in the region’s growing season. The report also documented threats to the Arctic fox, which is losing ground to the more common red fox as habitat changes.

Measurements of massive phytoplankton blooms below the summer sea ice suggest that earlier estimates of biological production at the bottom of the marine food chain may have been ten times lower than was occurring.

“Popular perceptions of the Arctic as a distant, icy, cold place that has little relevance to those outside the region are being challenged”, said Martin Jeffries, co-editor of the 2012 Report Card and Arctic science adviser, Office of Naval Research & research professor, University of Alaska-Fairbanks. “As snow and ice retreat, the marine and terrestrial ecosystems respond, and talk of increased tourism, natural resource exploitation, and marine transportation grows. The Arctic Report Card does a great service in charting the many physical and biological changes.”

Key findings from the report include:

  • Snow cover: A new record low snow extent for the Northern Hemisphere was set in June 2012, and a new record low was reached in May over Eurasia.
  • Sea ice: Minimum Arctic sea ice extent in September 2012 set a new all-time record low, as measured by satellite since 1979.
  • Greenland ice sheet: There was a rare, nearly ice sheet-wide melt event on the Greenland ice sheet in July, covering about 97 percent of the ice sheet on a single day.
  • Vegetation: The tundra is getting greener and there’s more above-ground growth. During the period of 2003-2010, the length of the growing season increased through much of the Arctic.
  • Wildlife & food chain: In northernmost Europe, the Arctic fox is close to extinction and vulnerable to the encroaching Red fox. Additionally, recent measurements of massive phytoplankton blooms below the summer sea ice suggest that earlier estimates of biological production at the bottom of the marine food chain may have been ten times lower than was occurring.
  • Ocean: Sea surface temperatures in summer continue to be warmer than the long-term average at the growing ice-free margins, while upper ocean temperature and salinity show significant interannual variability with no clear trends.
  • Weather: Most of the notable weather activity in fall and winter occurred in the sub-Arctic due to a strong positive North Atlantic Oscillation, expressed as the atmospheric pressure difference between weather stations in the Azores and Iceland. There were three extreme weather events including an unusual cold spell in late January to early February 2012 across Eurasia, and two record storms characterized by very low central pressures and strong winds near western Alaska in November 2011 and north of Alaska in August 2012.

Apart from one or two exceptions, the scientists said the air temperatures were not unusually high this year relative to the last decade. Nevertheless, they saw large changes in multiple indicators affecting Arctic climate and ecosystems; combined, these changes are strong evidence of the growing momentum of Arctic environmental system change.

The record-breaking year also indicates that it is unlikely that conditions can quickly return to their former state.

“The record low spring snow extent and record low summer sea ice extent in 2012 exemplify a major source of the momentum for continuing change,” Jeffries said. “As the sea ice and snow cover retreat, we’re losing bright, highly reflective surfaces, and increasing the area of darker surfaces—both land and ocean—exposed to sunlight. This increases the capacity to store heat within the Arctic system, which enables more melting—a self-reinforcing cycle.”

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