New research indicates that the Earth is absorbing an alarming amount of heat. The amount of incoming solar radiation trapped on the surface and in the waters has doubled in the last 15 years.
The findings are a blaring warning that the planet is fast-changing outside the constraints that have permitted civilization to survive. NASA and the National Oceanic and Atmospheric Administration published the study, titled, "Satellite and Ocean Data Reveal Marked Increase in Earth's Heating Rate," in Geophysical Research Letters.
Climate science 101 is all about the Earth's energy balance. (It was a talk on it that drew my wife into the topic, so thank you, scientists, for researching it.) It receives solar energy and outputs an equal and opposite amount of energy back into space, equivalent to how an ordinary person is paid and then spends their money on bills. The Earth's budget, on the other hand, is becoming increasingly uneven.
NASA and NOAA scientists decided to investigate this energy imbalance, which is now only 0.3 percent, implying that the planet is absorbing more energy from the sun than it is returning to space. Here on Earth, that energy has to do something, and the ultimate consequence is usually more heat. The researchers used satellite data from the top of the atmosphere and from a network of autonomous floats that collect data in the upper 2,000 meters of the ocean to see how that imbalance has altered since 2005. The first indicates how much energy is coming in and going out, while the second shows where 90 percent of the world's heat is kept.
The findings reveal a significant shift in the 15 years of data. Since 2005, the Earth has approximately doubled the amount of heat it has absorbed, according to both databases. The fact that the two data sets coincide so closely gives the researchers confidence in the alarming trend.
"It is a massive amount of energy," Gregory Johnson, an oceanographer for NOAA's Pacific Marine Environmental Laboratory and co-author of the study, told the Washington Post. "It's such a hard number to get your mind around."
He used analogies like exploding four atomic bombs equivalent to the one dropped on Hiroshima every second, or all 7 billion-plus of us firing up 20 electric tea kettles and just letting them run in an attempt to help you get your head around it.
Solar Cycles Not An Issue
While denialists would immediately raise the problem of solar cycles, the research reveals that this isn't the case, with changes in solar radiation being described as "negligible." Changes in cloud cover and surface reflectivity are the primary sources of the deepening imbalance. Clouds are being affected by climate change. Gizmodo said this is an area of ongoing research. Rising temperatures are also changing the Earth's reflectance, particularly as Arctic sea ice melts. As a result, the darker ocean water may absorb more heat. The report also mentions that so-called "trace gases" - like carbon dioxide and other forms of pollution from human activities - are adding to the imbalance.
Some of the fluctuations in cloud cover could be linked to natural climatic shifts like El Niño and the Pacific Decadal Oscillation (which is essentially an El Niño-like phenomenon that lasts for decades rather than a year). Both have been in phases that allow the globe to absorb more heat, notably the PDO. Those natural patterns, however, are insufficient to shift the energy balance in the incorrect direction.
Norman Loeb, the study's principal author and a researcher at NASA's Langley Research Centre, said in a press release it's likely a mix of anthropogenic forcing and internal variability.
While everyone who has lived on Earth for the past 15 years can see that the energy imbalance has negative consequences, the study helps to quantify it in stark terms. It also paves the way for researchers to dig deeper into what's going on, including how it might affect world average temperatures, sea-level rise, and other climate-related phenomena.
Worryingly, if the imbalance worsens, more drastic climate change impacts may occur sooner than projected.
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