27 Sep 2012:
Are Warmer than Any Time in 1,800 years
Summer temperatures on the Norwegian archipelago of Svalbard in the High Arctic are now higher than during any time over the last 1,800 years
, including a period of higher temperatures in the northern hemisphere known as the Medieval Warm Period
, according to a new study. In an analysis of algae
Arctic Tipping Point:
A North Pole Without Ice
Scientists say this year’s record declines in Arctic sea ice extent and volume are powerful evidence that the giant cap of ice at the top of the planet is on a trajectory to largely disappear in summer within a decade or two, with profound global consequences.
buried in deep lake sediments, a team of scientists calculated that summer temperatures in Svalbard since 1987 have been 2 to 2.5 degrees Celsius (3.6 to 4.5 degrees F) warmer than during the Medieval Warm Period, which lasted from roughly 950 to 1250 AD. The Medieval Warm Period is often cited by climate change skeptics as proof that the planet has experienced periods of high temperatures in recent centuries unrelated to the burning of fossil fuels. “Our record indicates that recent summer temperatures on Svalbard are greater than even the warmest periods at that time,” said William D’Andrea, a climate scientist at Columbia University. The algae, which make more unsaturated fats in colder periods and more saturated fats in warmer periods, reveal critical clues about past climates. Scientists were able to date the lake specimens by analyzing grains of glass emitted by a series of well-known Icelandic volcanoes that left unique chemical time markers. The study is published in the journal Geology
Yale Environment 360 is
a publication of the
Yale School of Forestry
& Environmental Studies
Yale Environment 360
articles are now available in Spanish and Portuguese on Universia
, the online educational network. Visit the site.
Business & Innovation
Policy & Politics
Pollution & Health
Science & Technology
Antarctica and the Arctic
Central & South America
A three-part series Tainted Harvest
looks at the soil pollution crisis in China, the threat it poses to the food supply, and the complexity of any cleanup. Read the series.
is now available for mobile devices at e360.yale.edu/mobile
The Warriors of Qiugang
, a Yale Environment 360
video, chronicles a Chinese village’s fight against a polluting chemical plant. It was nominated for a 2011 Academy Award for Best Documentary Short.
Watch the video.
Top Image: aerial view of Iceland
. © Google & TerraMetrics.
, winner of the Yale Environment 360 Video Contest, documents the work of African researchers monitoring wildlife in Uganda's remote Bwindi Impenetrable National Park. Watch the video.