The 'Hockey Stick' Lives - NYTimes.com

The 'Hockey Stick' Lives - NYTimes.com

Few images in the climate change debate have stirred as much controversy as the storied “hockey stick” graph, which shows average temperatures in the northern hemisphere holding roughly steady for 900 years or so, until the 20th century, when they rise sharply.

Two new studies bolstering the “hockey stick” hypothesis were published just recently. One that appeared this month in the journal Geophysical Research Letters analyzed seashell deposits on the North Atlantic seafloor and determined that 20th-century warming in the region “had no equivalent during the last thousand years.”

Another study, in The Journal of Geophysical Research, analyzed ice cores from glaciers in the eastern Bolivian Andes dating back to 400 A.D.

“The last decades of the past millennium are characterized again by warm temperatures that seem to be unprecedented in the context of the last 1,600 years,” the researchers concluded.