The Earth is warming much faster than expected, with the amount of trapped heat from the sun approximately doubling between 2005 and 2019, says a new study co-authored by NASA and the U.S. National Oceanic and Atmospheric Administration (NOAA).
To uncover this “energy imbalance”, researchers compared satellite data on how much heat is entering and exiting the atmosphere with ocean temperature data captured by sea-going floats, reports The Guardian. The results, just published in the journal Geophysical Research Letters, are “unprecedented” and “alarming,” the study authors say.
Lead author and NASA researcher Norman Loeb told The Guardian that using these two “very independent” data sources allowed his research team to arrive at a very robust conclusion. “[They] are in really, really good agreement, and they’re both showing this very large trend, which gives us a lot of confidence that what we’re seeing is a real phenomenon and not just an instrumental artifact,” he said.
What remains uncertain is how much of this “phenomenon” owes to human activity. Noting that a “naturally occurring” shift to a warmer phase in the Pacific Ocean is probably involved to some measure, Loeb said the energy imbalance is “likely a mix of anthropogenic forcing and internal variability.”
What is certain, he stressed, is that “the magnitude of the increase is unprecedented.”
The Washington Post explains that, back in 2005, the Earth was radiating back into space “about 239.5” of the 240 watts per square metre of energy it received from the sun, “creating a positive imbalance of about half a watt.” A scant 15 years later, “that gap had nearly doubled to about one full watt per square metre.”
Study co-author and NOAA oceanographer Gregory Johnson said the comprehensive nature of the findings helped increase scientists’ understanding of the climate crisis. “Other common metrics, such as air temperature, only catch a fraction of the effect of the sun’s heat,” the Post explains. “The imbalance, he said, measures ‘the full amount of heat that goes into the climate system’.”