Atmospheric Science:
Monsoons and Meltdowns
Jeffrey P. Severinghaus
What do periods of weak low-latitude rainfall have to do with the meltdown of great ice sheets? On page 248 of this issue, Cheng et al. (1) show that this counterintuitive association contains a hot clue about the much-debated causes of the ice age cycles that end every 100,000 years or so in a collapse of the great Northern Hemisphere ice sheets (a glacial termination). Understanding this collapse is relevant to human affairs both past and future, because the collapse typically causes a subsequent period of unusual climatic stability and warmth (an interglacial period), exemplified by the past 11,700 years of relatively stable climate in which human agriculture and civilization have flourished (2). Further, the future stability of ice sheets is an urgent question facing society today (3).
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093–0244, USA.
E-mail: jseveringhaus{at}ucsd.edu
