SEBASTIAN GOLLNOW
Between 2005 and 2019 the so-called energy imbalance of the earth almost doubled, said researchers from the American climate agency NOAA and the space agency Nasa in the journal “Geophysical Research Letters”. This trend is primarily due to an increase in absorbed solar radiation due to reduced reflection from clouds and sea ice. At the same time, the long-wave radiation from the earth into space, through which energy and thus heat is given off, has decreased due to more greenhouse gases in the atmosphere, among other things.
It is based on a sensitive energetic balance on the earth: On the one hand, sun rays are absorbed by the atmosphere and the earth’s surface, on the other hand, the earth emits infrared radiation into space. If both processes are balanced, the energy balance is balanced. A positive energy balance means that the earth is warming up. Since about 90 percent of this excess energy is absorbed by the oceans, the water in the seas heats up.
However, the energy imbalance can also be influenced by natural factors. According to the scientists, the Pacific Decade Oscillation (PDO) in particular may have played a role. In this case, the temperature of the surface water in the Pacific changes significantly – a particularly warm phase, such as between 2014 and 2020, helps the earth to absorb significantly more solar radiation.
“It’s probably a mixture of human drivers and internal (Earth) change,” said the study’s head, Norman Loeb. Human and natural factors combined “caused a warming which leads to a rather large change in the earth’s energy imbalance. The extent of the increase is unprecedented. ” Loeb emphasized that the study is only a snapshot of long-term climate change and that it is not possible to predict with any certainty what the earth’s energy budget might look like in the coming decades. (SDA)