Current observational tools cannot account for roughly half of
the heat that is believed to have built up on Earth in recent
years, according to a "Perspectives" article in this week's
issue of the journal Science. Scientists at the National Center
for Atmospheric Research (NCAR) in Boulder, Colo., warn that
satellite sensors, ocean floats, and other instruments are
inadequate to track this "missing" heat, which may be building
up in the deep oceans or elsewhere in the climate system. "The
heat will come back to haunt us sooner or later," says NCAR
scientist Kevin Trenberth, the article's lead author. "The
reprieve we've had from warming temperatures in the last few
years will not continue. It is critical to track the build-up of
energy in our climate system so we can understand what is
happening and predict our future climate." The authors suggest
that last year's rapid onset of El Niņo, the periodic event in
which upper ocean waters across much of the tropical Pacific
Ocean become significantly warmer, may