NASA data revealed the cold waters of the deep ocean have not warmed significantly since 2005, furthering the mystery of why global warming has slowed down.
Researchers at NASA's Jet Propulsion Laboratory (JPL) analyzed satellite data from 2005 to 2013 and found ocean water under 1.24 miles below the surface has not warmed measurably. These findings are not believed to "throw suspicion" on global climate change.
"The sea level is still rising," said study coauthor Josh Willis of JPL. "We're just trying to understand the nitty-gritty details."
Greenhouse gases are rising as usual, but in the 21st century global average surface air temperatures have stayed relatively stagnant. The temperature of the upper level of ocean waters has been on the incline, but not fast enough to account for the stable air temperatures.
Climate scientists have been on the hunt for this "missing heat," and in the past researchers have wondered if the lower depths of the ocean have been absorbing it; these new findings dispute this theory.
This recent study is the first to use satellite data as well as direct temperature measurements of the upper ocean. Since 2005 researchers have been taking the temperature of the upper ocean, but the deeper regions have not been as easy to measure.
"The combination of satellite and direct temperature data gives us a glimpse of how much sea level rise is due to deep warming. The answer is -- not much," said JPL's William Llovel, lead author of the study published Sunday in the journal Nature Climate.
Since water expands as it gets warmer, researchers believe the sea level has risen as a result of this expansion as well as melting sea ice.
Using in-depth calculations and data from NASA's Jason-1 and Jason-2 satellites, along with the agency's Gravity Recovery and Climate Experiment (GRACE) satellites, researchers were able to look at how much of the global sea level rise was a result of expansion in the upper ocean and how much came from meltwater. What was left over was attributed to expansion in the lower levels of the ocean; which ended up accounting for essentially zero of the rise.
