Photo courtesy of NASA

by Breanna Draxler

Global temperatures are set to rise, even though a newly discovered heat sink puts it off for a few years.

Scientists at the National Center for Atmospheric Research released an analysis last Tuesday that determined that deep ocean waters absorb atmospheric heat. This results in a decade-long lag time between rising heat input and rising air temperatures.

It’s as though the earth has rented an underwater storage unit for its excess heat. The lease is good for 10 years, after which time the heat will be up for grabs. And the atmosphere is predicted to be the highest bidder.

NCAR scientists say the past decade has been an example of this 10-year heat storage lease in action. Greenhouse gases have been on the rise since the turn of the century, and more solar heat is entering the atmosphere than is leaving through radiation.  That means there is more heat in the system today, yet global air temperature has increased only minimally. This “missing heat” was unaccounted for until scientists started looking for a deep ocean reservoir for heat.

To find that deepwater sink, scientists used Supercomputer simulations of global temperatures to examine the complex climatic interplays of atmosphere, land, oceans and sea ice. From these, they concluded that the “missing” heat is being held in ocean water at depths below 1,000 feet.

The scientists predict this lease on underwater heat storage to have a 10-year limit. So while scientists predict more of these short-term plateaus on the graph of global temperatures in the future, overall temperature will continue to rise.

Precisely where greenhouse gases are produced and absorbed is a question that has vexed scientists for years. As of last Friday, they now have a clearer picture of the global distribution of these gases in the atmosphere. And they have HIPPO to thank. 

HIPPO stands for HIAPER Pole-to-Pole Observations. It’s the name given to a series of research flights that mapped global greenhouse gas concentrations from the Arctic to the Antarctic.  The research team included scientists from the National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration, and Harvard University. 

The scientists tested for 80 different particles and greenhouse gases, including methane and carbon dioxide. 

Their data collection method improved upon that of existing ground stations—namely the global tall-tower network operated by NOAA. The airborne method could pinpoint the concentrations of gases in higher definition.   The jet’s altitude ranged from 500 to 45,000 feet, which also let scientists figure out the vertical distributions of these gases.

The new data have informed scientists more precisely about the sources and sinks of greenhouse gases.  For example, black carbon particles—emitted by diesel engines, smokestacks and fires—are much more prevalent and widely distributed than previously thought.

The HIPPO project began in 2009. It was co-sponsored by the National Science Foundation and NOAA. Last Friday marked the landing of the project’s fifth and final mission. 

Results from the HIPPO project will provide baseline measurements of global greenhouse gases.  They’ll also allow scientists to improve atmospheric models for future predictions.