A huge patch of water in the Pacific Ocean along the North American coast warmed above typical seasonal temperatures in late 2013.
This increase, named the “Blob” after a 1958 horror film about an alien life form that grows as it consumes everything in its path, lasted an abnormally long period of time and decimated sea life, killing fish, birds, and many other marine animals, particularly in 2015 and 2016.
The Blob has made at least two appearances since then, and now, a team of scientists has pinpointed the systematic warming in the Pacific Ocean that spurred the Blob’s rise, according to a study published in the journal Nature Communications Earth and Environment. Their modeling reveals the source of the Blob is not natural climatic variation, but rather human influences.
A team of researchers led by Armineh Barkhordarian, an expert on atmospheric science and member of Universität Hamburg’s Cluster of Excellence “Climate, Climatic Change, and Society,” demonstrated how the long-term warming pool has contributed to local marine heatwaves.
The most recent marine heatwave, which lasted from 2019 to 2021, caused water temperatures to rise by up to six degrees Celsius. According to the study, the extreme occurrence was directly caused by rising manmade greenhouse-gas emissions. The press release states that the probability of such a heatwave happening without all the excess greenhouse gasses humans have pumped into the atmosphere is less than one percent.
The study also discovered that, on average over the previous 25 years, the water temperature above the warming pool in the northeast Pacific increased by 0.05 degrees Celsius (32.09 degrees Fahrenheit) per year. During the cold season, the team also noticed a decrease in low clouds, which generally have a cooling effect on the waters below. During the winter, this intensifies the atmospheric high-pressure systems over the warm water pool.
Overall, the area experienced summers that were 37 days longer on average and winters that cooled off less. As a result, there have been 31 marine heatwaves in this area alone during the past 20 years as opposed to just nine from 1982 to 1999.
“This warming pool will continue to increase the water temperature in the future, increasing both the frequency and intensity of local marine heatwaves. The sharp increase in average water temperature is pushing ecosystems to their limits,” Barkhordarian explained in a press release.
The findings are aligned with previous research that found marine heatwaves are 20 times more likely now due to human-caused climate change.
“More frequent and extreme marine heatwaves are a serious burden for affected ecosystems. This not only poses a tremendous threat to biodiversity; it can also push these marine ecosystems past a tipping point, after which they can no longer recover,” Barkhordarian said. “The discovery of the long-term warming pool will now provide us with crucial information on the likelihood of such extreme events in the future.”
Huge patches of unusually warm water are becoming more common around the world, with new warm areas emerging in the North Pacific Ocean and elsewhere. Scientists are using what they’ve learned from The Blob to help predict how future marine heat waves will evolve. However, if global warming continues, heat waves will become more frequent, larger, more powerful, and last longer. In fact, oceans are facing a mass extinction event comparable to the “Great Dying.”
Our oceans could dramatically change by the end of the century, which further highlights the urgency of ending our reliance on fossil fuels and reducing greenhouse emissions.