Atmosphere Journal Entry
Arctic is Warmest in 2,000 Years (September 21, 2009)
A new study shows the Arctic is warmer now than it's been in 2,000 years. NASA.
The Arctic was warmer over the past decade than in any other 10-year period over the past 2,000 years, according to a new study by an international research team. The warming trend has been going on since the start of the Industrial Revolution, reversing a long cooling trend. The huge jump in greenhouse gases from the burning of fossil fuels is to blame.
The researchers looked at sediment cores from lakes in the Arctic. The samples provided data on the growth rate of plants buried below the ice long ago. The scientists also studied tree ring and glacier ice core data.
Some scientists link the cooling trend that started about 2,000 years ago to cyclical changes in Earth's elliptical orbit and the wobble of its axis. But the cooling phase suddenly reversed in the 1800s when greenhouse gas levels rose sharply as the number of factories mushroomed. The planet, especially the Arctic, has been getting warmer ever since. Globally, average temperatures climbed 1 degree Fahrenheit (0.6 degrees Celsius) over the past century. But the rise has been more than twice as big in the Arctic.
Recent photos of glaciers offer additional proof. A USGS photographer took pictures of about 2,000 glaciers over the past 35 years. More than 98 percent of them are shrinking as their ice and snow melt from rising temperatures.
This summer, temperatures hit record highs in the Arctic. Curiously, the summer melting of sea ice slowed compared to the record melting seen in 2007. Meteorologists say this was due to shifting wind patterns over the Arctic Ocean that kept sea ice from reaching the warmer waters of the Pacific. Still, the total area covered by the sea ice is way below the 20-year average.
