PERSPECTIVES PALEOCLIMATE: Climate Change Across the Hemispheres

• Main Author: Nicholas Shackleton
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: Antarctic; Greenland; The Antarctic; Antarc*; Antarctica; Greenland ice cores; ice core; North Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.475.7434; http://rockbox.rutgers.edu/~jdwright/GlobalChange/Shackleton_Prespective_2001.pdf

Ice cores from Greenland have provided evidence that dramatic and rapid changes in air temperature occurred during the last ice age. Temperatures over Greenland changed by as much as 10°C within decades. It is generally accepted that simultaneous changes in temperature must have occurred in the entire North Atlantic region because the Greenland temperature changes were associated with migrations of the Atlantic polar front, the main boundary line between polar and temperate water masses, from near Greenland to as far south as the coast of southern Portugal. Ice-core records from Antarctica cover a much longer time interval than the Greenland ice cores (Antarctic ice cores document several ice-age cycles, Greenland only a single cycle), and at first the length of the Antarctic records attracted more attention than the finer-scale details. Recently it has become apparent that the Antarctic ice cores also record important temperature variability on millennial and shorter time scales. Comparison of records from the two hemispheres may thus help to answer some of the following questions: Are temperature changes on millennial time scales global in extent? Are changes in the two hemispheres synchronous? Or does a "polar