'Missing' heat may affect future climate change

Some research by Kevin Trenberth and John Fasullo, from the University Corporation for Atmospheric Research: 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 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.

….In their Perspectives article, Trenberth and Fasullo explain that it is imperative to better measure the flow of energy through Earth’s climate system. For example, any geoengineering plan to artificially alter the world’s climate to counter global warming could have inadvertent consequences, which may be difficult to analyze unless scientists can track heat around the globe. Improved analysis of energy in the atmosphere and oceans can also help researchers better understand and possibly even anticipate unusual weather patterns, such as the cold outbreaks across much of the United States, Europe, and Asia over the past winter.

…Satellite measurements indicate that the amount of greenhouse-trapped solar energy has risen over recent years while the increase in heat measured in the top 3,000 feet of the ocean has stalled. Although it is difficult to quantify the amount of solar energy with precision, Trenberth and Fasullo estimate that, based on satellite data, the amount of energy build-up appears to be about 1.0 watts per square meter or higher, while ocean instruments indicate a build-up of about 0.5 watts per square meter. That means about half the total amount of heat is unaccounted for….

Satellite sensors show that the amount of greenhouse-trapped solar energy, or heat, has risen over recent years. But in the past decade, there has been a growing divergence between the satellite readings and ocean observations that indicate the build-up of heat is slowing. This "missing" heat could, in part, be the result of instrument error or incorrect data processing, but much of it may be going into the deep ocean or elsewhere on Earth that is beyond the reach of current sensors. This graph shows simplified estimates of the measurements of heat. (Courtesy Science, on the UCAR website.)