Oops, Scientists May Have Miscalculated Our Global Warming Timeline

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• The Paris Climate Accords in 2015 set an ambitious (and necessary) goal of keeping global temperatures 1.5 degrees Celsius above pre-industrial temperatures. But one study says we may have crossed that threshold a few years ago.

• Scientists at the University of Western Australia’s Ocean Institute studied long-lived Caribbean sclerosponks and created an ocean temperature timeline dating back to the 1700s.

• While the study claims we exceeded 1.5 degrees Celsius in 2020, other scientists question whether data from just one part of the world is enough to capture the enormous thermal complexity of our oceans.

Whatever your stance is climate change (it’s real, let’s move on), it’s impossible to miss the almost ubiquitous call to action to “keep the temperature not exceeding 1.5 degrees Celsius compared to pre-industrial levels.” Over the past few years, this somewhat bureaucratic phrase has become a rallying cry for the climate-conscious.

This ambitious goal was first revealed after: Paris Climate Agreementand it defines a kind of climate threshold – if we exceed a long-term average temperature increase of 1.5 degrees Celsius and stay at these levels for several years, we will cause serious harm to ourselves and our environment.

There’s some bad news in an article from the University of Western Australia’s Ocean Institute: Earth may have passed this threshold four years ago.

Published in magazine Nature Climate ChangeThe article reaches this conclusion in an unusual way; By analyzing six sclerosponges, one type sea ​​sponge clinging to underwater caves in the ocean. These sponges are widely studied by climate scientists and “natural archives“Because they grow so slowly, say, a fraction of a millimeter per year. This actually allows them to lock climate data into their limestone skeletons, not entirely dissimilar to tree rings or ice cores.”

By analyzing the strontium/calcium ratios in these sponges, the team was able to effectively calculate water temperatures dating back to 1700. The sponges’ watery home in the Caribbean is also a plus because of the large oceans. currents Do not distort or distort temperature readings. This data could be particularly useful, as direct human measurement of sea temperature dates back to about 1850, when sailors dipped buckets into the ocean. That’s why the Intergovernmental Panel on Climate Change (IPCC) uses the years 1850 and 1900 as the pre-industrial baseline. according to website ground.

“The big picture is that global warming “The clock on emissions reductions has been pushed forward by at least a decade to minimize the risk of dangerous climate change,” said Malcolm McCulloch, lead author of the study. Associated Press. “Actually, time is running out.”

The study concludes that the world began to warm about 80 years earlier than the IPCC predicted, and that we have already exceeded 1.7 degrees Celsius in 2020. This is a big “wow, if it’s true” moment, but some scientists are skeptical. Such a scientist talk with Live ScienceHe said: “It would be naive to claim that instrumental records are wrong based on paleosponges in one part of the world.” World … Frankly, it doesn’t make any sense to me.” Other experts expressed that he would like to see more data Before completely upending the IPCC’s climate targets, which say the Earth is currently subject to a long-term temperature change of around 100,000 1.2 degrees Celsius.

Unfortunately, although sponges If we are wrong, there is growing evidence that we are now in the process of passing the 1.5 degree threshold. This January was the hottest January on record, running 1.7 degrees above pre-industrial temperatures. Accordingly New ScientistThis means we have been above 1.5 degrees of change for at least a year. This doesn’t push the long-term average above the 1.5 line, but it’s certainly a sign that we’re quickly approaching it.

Whatever the percentage, one thing is certain: Climate change is an all-encompassing crisis. To make the planet habitable in the future, humans need to reduce emissions immediately; After all, that’s what sea sponges tell us.

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