Ominous new research shows that the Earth is taking in a shocking amount of heat. In the past 15 years, the amount of incoming solar radiation trapped on the surface and in the oceans has doubled.
The findings, published in Geophysical Research Letters by scientists at NASA and the National Oceanic and Atmospheric Administration, are a deafening klaxon that the planet is rapidly shifting outside the boundaries that have allowed civilisation to thrive.
The Earth’s energy balance is climate science 101. (It was actually a presentation on it that drew my wife into the field, so thank you for studying it, scientists.) The Earth is just like you and me. It has a budget. It absorbs energy from the sun and emits an equal and opposite amount of energy back into space, much like an average person gets paid and then uses that money to pays bills. However, the Earth’s budget is becoming increasingly unbalanced.
Scientists at NASA and NOAA decided to study this energy imbalance, which is currently just 0.3%, meaning the planet is currently taking up more energy from the sun than it’s putting back into space. That energy has to do something here on Earth, and the end result is generally more heat. To gauge how that imbalance has changed since 2005, the researchers pulled satellite data looking at the top of the atmosphere and a network of autonomous floats that gather data in the upper 2,000 metres of the ocean. The former shows what kind of energy is coming and going while the latter offers a look at where 90% of the world’s heat gets stored.
The results show a major change over the 15 years of records. Both datasets show the planet has roughly doubled the amount of heat it has taken on since 2005. That the two sources of data are in such close agreement gives the researchers confidence in the disturbing 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.”
Among the analogies he mentioned in an attempt to help you get your head around it are that the heat is equal to dropping 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. I appreciate the effort, but even those stats are confounding. I don’t even have 20 outlets in my apartment.
While deniers will be quick to screech “bUt WhAt AbOuT sOlAr CyClEs,” the research shows that’s simply not the issue here, calling changes in solar radiation “negligible.” The main causes for the deepening imbalance are tied to changes in cloud cover and reflectivity of the surface. Climate change is having an impact on clouds, though it’s an area of active research. And rising temperatures are absolutely altering the reflectivity of the Earth, particularly by melting Arctic sea ice. That allows darker ocean water to take up more heat. The study also notes that what it innocuously refers to as “trace gases” — i.e. carbon dioxide and other forms of pollution from human activities — are contributing to the imbalance as well.
Some of the cloud cover changes may be tied to natural climate shifts, such as El Niño and the Pacific Decadal Oscillation (which is basically a pattern somewhat similar to El Niño that lasts for decades rather than a year). Both, particularly the PDO, have been in phases conducive for the planet to absorb more heat. But those natural patterns alone aren’t enough to send the energy balance spiralling in the wrong direction.
“It’s likely a mix of anthropogenic forcing and internal variability,” Norman Loeb, the study’s lead author and a researcher at NASA’s Langley Research Centre, said in a press release. “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.”
While it’s readily apparent to anyone who has lived on Earth these past 15 years that the energy imbalance is having deleterious effects, the study helps quantify it in stark terms. And it points a pathway forward for researchers to analyse what’s going on in more detail, including how it could affect the global average temperature, sea level rise, and other more familiar phenomena associated with the climate crisis.
Worryingly, if the imbalance continues to grow more lopsided, it could lead to more dramatic climate change impacts sooner than expected. I certainly respect the need for more research, particularly the role natural climate shifts could be playing. But I’d also appreciate it if the world got a handle on carbon pollution so researchers can’t test that part of their hypothesis in real life.