In very basic terms, global warming is what happens when we leave the car parked in the sun and go inside after a couple of hours. The interior temperature is much higher due to heat being trapped inside the vehicle. That’s what they do greenhouse gases with our planet. And that accumulated heat is energy. According to an article published in Earth System Science Data, global warming has trapped an enormous amount of energy in Earth’s atmosphere over the past half century.
Study authors Andrew King and Steven Sherwood, both climate scientists at the University of New South Wales (Australia) estimate that, between 1971 and 2020, about 380 zettajoules, or 380,000,000,000,000,000,000,000 joules, of energy have been trapped by global warming. Such a large number is difficult to put into context but the authors have put it into perspective by comparing the energy with that released by nuclear weapons and it turns out that it is the equivalent to about 25 billion atomic bombs similar to the “Little Boy”, the atomic bomb dropped on Hiroshima on August 6, 1945.
Even more mind-boggling, the energy absorbed by the planet during this time period probably equals only about 60% of total emissions of greenhouse gases, so the actual number is even higher, King and Sherwood point out. But such a large amount of energy is also puzzling, because based on that amount of heat trapped in the atmosphere, the average global temperature should have risen tens of degrees since pre-industrial times, instead of 1.2 degrees Celsius. So where has all this extra energy gone?
What saves us are the oceans, for now
According to the study data, the oceans have absorbed about 89% of the energy (338.2 zettajoules), the Earth’s surface has absorbed 6% (22.8 zettajoules), 4% (15.2 zettajoules) has melted regions of the cryosphere (the part of Earth’s climate system that includes snow, sea ice, freshwater ice, icebergs, glaciers, and polar caps) and only 1% has remained in the atmosphere and that is the percentage that we “suffer”.
Returning to the simile of the car, it is as if most of the heat had been absorbed by the fabrics of the seats, the roof lining and the dashboard: although the interior temperature has risen, if it were not for these elements in the car, it would be much higher.
The upside is that most of the heat absorbed by the seas is trapped in the top 1 kilometer of the oceans and this is what has spared humanity the brunt of climate change so far, but has also caused massive increases in sea surface temperatures, which has accelerated the melting of the poles, damaged marine ecosystems, increased the severity of tropical storms, and begun to alter ocean currents, which in turn influence temperatures on land and the cycle starts again.
However, the oceans will not protect our planet forever, the authors conclude, so we must begin to rapidly decrease greenhouse gas emissions by decarbonizing the global economy to ensure our future survival. “We are in a race, and the stakes are high: ensuring a livable climate for our children and for nature.” The first solution is obvious: we should get out of the car…
