Robert Rohde, chief scientist at Berkeley Earth, is great at climate science and at communicating it. He just posted an illuminating thread on X breaking down what’s going on with the extreme heating of the North Pacific Ocean (even as the tropical Pacific appears headed for a La Niña cooldown, according to NOAA). I’ve unrolled his posts for you below.
He explains how an unintended consequence of a rapid cut in shipping pollution - kind of an accidental sunblocking geoengineering experiment - played a role. I wonder what Rep. Marjorie Taylor Greene will think of that after her hearing on weather control and geoengineering? See hearing witness
But first, here’s an introduction to the North Pacific heat wave from Jeff Berardelli, chief meteorologist at the Tampa-area station WFLA and a friend from his days at Columbia (via his @weatherprof account on X):
It's hard to overstate just how off the charts warm the Pacific is right now. The swath of the basin from California to Japan (a HUGE area) from 25N to 60N is ~3F (1.6C) above normal. To put it into math terms that is 6 Sigma/ standard deviations above the mean. I won't bother calculating the chances of this happening against the late 20th century climate - let alone the pre-climate change climate - because the numbers would show it simply could never happen without global warming. So let's talk about why this is happening. Since the last El Nino a couple of years ago the ocean has been rearranging its warm/cool water, as it typically does as a normal part of it's natural oscillation. (This summer a record ridge/ heat dome was parked over the N Pacific). But each next time this configuration lines up (warm north Pacific/ cool tropical Pacific) it piles on a higher and higher baseline temperature over time due to greenhouse warming, air pollution reduction, and the feedbacks (clouds & direct insolation) of both. So we end up with the bottom chart which shows the standardized anomaly (departure from normal) is sloping upward at a very unnatural rate an alarming rate.
Here’s Rohde’s explanation, which finds a significant role in the sharp reduction in sooty sulfurous pollution from shipping:
The Northern Pacific Ocean is currently smashing temperature records. And it is reaching these levels far earlier than the current generation of climate models had expected.
Nearly the entire Northern Pacific is experiencing a strong marine heat wave, with record warmth in Japan and abnormally warm waters stretching all the way to the North American coastline.
Like most record-setting events, this warmth has multiple causes. It's a combination of short-term weather over the last few months and global warming over decades.
But it is also probably, in part, the result of an accidental experiment in large-scale geoengineering. What do I mean by an accidental experiment in geoengineering?
In 2020, new anti-pollution regulations to protect human health (IMO2020) cut the allowable sulfur content in marine fuels. This slashed shipping-related sulfur pollution ~85% overnight.
The North Pacific and North Atlantic are the world's great shipping corridors.
Cutting ship-borne sulfur pollution had the secondary effect of clearing the skies in these areas, reducing ship-track associated clouds, and letting a bit more sunlight be absorbed by the ocean.
Cutting air pollution over the ocean isn't the whole story, but likely adds a few to several tenths of a degree Celsius to the temperature of this ocean basin.
Contributing, in part, to the current Northern Pacific records and the North Atlantic records in 2023/2024.
Does reduced sulfur pollution explain the divergence between climate models and observations?
Not sure, but it likely explains at least some of it.
The current generation of models did not anticipate the marine sulfur regulations, and so will not have included that impact.
The next generation of model results, which better reflect recent sulfur emission changes, will be appearing soon.
Hopefully they will clarify if we understand what is happening in the Pacific, but right now that warming is exceeding our models in a troubling way. [X thread is here]
It’s wonderful that we can rely on hard-working scientists like Rohde and Berardelli to help communicate what’s happening and why.
I hope those who can afford it will consider becoming paid subscribers. Helps me justify the time this take.s
Nice article. Somehow missed the demonstration that a major factor in the unexpected N Pacific warming is another “unplanned geoengineering experiment,” viz., the huge reduction in industrial aerosol emissions that the Chinese government has conducted since the 2008 Olympics. Hard to say which is more important, China or maritime reduction.
Wang, Hai, et al. (2024). "Atmosphere Teleconnections from Abatement of China Aerosol Emissions Exacerbate Northeast Pacific Warm Blob Events." Proceedings of the National Academy of Sciences 121: e2313797121 [doi:10.1073/pnas.2313797121].
Nice article. Somehow missed the demonstration that a major factor in the unexpected N Pacific warming is another “unplanned geoengineering experiment,” viz., the huge reduction in industrial aerosol emissions that the Chinese government has conducted since the 2008 Olympics. Hard to say which is more important, China or maritime reduction.
Wang, Hai, et al. (2024). "Atmosphere Teleconnections from Abatement of China Aerosol Emissions Exacerbate Northeast Pacific Warm Blob Events." Proceedings of the National Academy of Sciences 121: e2313797121 [doi:10.1073/pnas.2313797121].