The Climate Prediction Gap: Half of the Planet's Heat Can't be Accounted For
| Marilyn Sigman, Alaska SeaGrant/MAP
Tags: Climate Change, Heat storage in the Ocean
Source: National Center for Atmospheric Research (NCAR) website
April 15, 2010
BOULDER—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 the April 15 issue of Science. Scientists at the National Center for Atmospheric Research (NCAR) warn in the new study 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 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 Niño, the periodic event in which upper ocean waters across much of the tropical Pacific Ocean become significantly warmer, may be one way in which the solar energy has reappeared.
The research was funded by the National Science Foundation, NCAR’s sponsor, and by NASA. A Science Perspectives piece is not formally peer-reviewed, but it is extensively reviewed by editors of the journal. Science had invited Trenberth to submit the article after an editor heard him discuss the research at a scientific conference.
Trenberth and his co-author, NCAR scientist John Fasullo, focused on a central mystery of climate change. Whereas satellite instruments indicate that greenhouse gases are continuing to trap more solar energy, or heat, scientists since 2003 have been unable to determine where much of that heat is going.
Either the satellite observations are incorrect, says Trenberth, or, more likely, large amounts of heat are penetrating to regions that are not adequately measured, such as the deepest parts of the oceans.
Compounding the problem, Earth’s surface temperatures have largely leveled off in recent years. Yet melting glaciers and Arctic sea ice, along with rising sea levels, indicate that heat is continuing to have profound effects on the planet.
More, including a video presentation by Trenberth
The abstract of the Trenberth and Fasullo article, Climate Change: Tracking Earth's Energy, in the April 15 issue of Science
By measuring the net radiative incoming and outgoing energy at the top of Earth's atmosphere, it is possible to determine how much energy remains in the Earth system. But where exactly does the energy go? The main energy reservoir is the ocean, which sequesters energy as heat. Because energy is exchanged between the atmosphere and the ocean, this heat can resurface at a later time to affect weather and climate on a global scale. A change in the overall energy balance will thus sooner or later have consequences for the climate.
Existing observing systems can measure all the required quantities, but it nevertheless remains a challenge to obtain closure of the energy budget. This inability to properly track energy—due to either inadequate measurement accuracy or inadequate data processing—has implications for understanding and predicting future climate. Full text of the article, by subscription.