Scientists at the National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA) have determined in new research that the Earth’s atmosphere has been trapping an “unprecedented” amount of heat, with the planet’s energy imbalance approximately doubling from 2005 to 2019.
NASA explained in a release Tuesday that the blue marble’s climate is determined by the balance between how much of the sun’s energy is absorbed in the atmosphere and at the surface and how much thermal infrared radiation is emitted into space.
According to a recent study published in Geophysical Research Letters, the sum of those two parts of energy determines whether Earth heats or cools.
“Continued increases in concentrations of well-mixed greenhouse gasses in the atmosphere and the long time-scales time required for the ocean, cryosphere, and land to come to thermal equilibrium with those increases result in a net gain of energy, hence warming, on Earth,” the study’s summary stated further. “Most of this excess energy (about 90%) warms the ocean, with the remainder heating the land, melting snow and ice, and warming the atmosphere.”
In order to reach these conclusions, the agency researchers compared data from NASA’s Clouds and the Earth’s Radiant Energy System (CERES) satellite sensors with a global array of measurements from “Argo” ocean floats.
“We show that these two independent approaches yield a decadal increase in the rate of energy uptake by Earth from mid-2005 through mid-2019, which we attribute to decreased reflection of energy back into space by clouds and sea-ice and increases in well-mixed greenhouse gases and water vapor,” the summary said.
Increases in greenhouse gases, like carbon dioxide and methane, trap heat in the Earth’s atmosphere and capture outgoing radiation, leading to warming and subsequently snow and ice melt and other changes.
“Earth’s energy imbalance is the net effect of all these factors,” NASA said in the release, noting that the study’s authors had examined changes in clouds, water vapor, combined contributions from trace gases and the output of light from the sun, surface albedo, aerosols and shifts in surface and atmospheric temperature distributions to reach their conclusions.
Additionally, the researchers found that a change in the Pacific Decadal Oscillation (PDO), a pattern of Pacific climate variability, to a warm phase “likely played a major role in the intensification of the energy imbalance.”
The agency said a similar warm PDO phase in 2014 through 2020 also caused a reduction in cloud coverage and an increase in the absorption of solar radiation.
“The two very independent ways of looking at changes in Earth’s energy imbalance 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,” Norman G. Loeb, lead author for the study and principal investigator for CERES at NASA’s Langley Research Center, said in the release. “The trends we found were quite alarming in a sense.”
“It’s likely a mix of anthropogenic forcing and internal variability,” he added. “And over this period they’re both causing warming, which leads to a fairly large change in Earth’s energy imbalance. The magnitude of the increase is unprecedented.”
Ultimately, the study determined that unless the rate of heat intake abates, the Earth is in for greater changes in climate.