It makes me wonder if much of the warming of the last 50 years is due to reduced air pollution. We burn much less coal in the northern hemisphere than we once did.
Of course they don’t. Desired policies are not allowed to have undesirable side effects, even if most people would agree that the trade offs are worth it.
Interesting article, well reasoned by Quico (as always). There is just one thing I don't understand. When I look at the satellite picture of the ship trails, it reminds me very much of airplane condensation trails. There have been numerous articles in the press over the last couple years on the WARMING effect of contrails. Why is the effect of these ships tracks the opposite, cooling instead of warming?
Ships produce a lot of aerosols but typically emit them low in the atmosphere – this changes clouds near to the Earth’s surface, making them brighter and creating a cooling effect.
Clouds formed from aviation are high up (10km up in the troposphere), and are very cold, making them good at stopping heat leaving the Earth and keeping it warm.
Clouds in general are a science communications shit show!! There are like 20 different hypothesized ways an aerosol can affect a cloud, the details change depending on weather conditions, season, altitude, it’s a nightmare. I mean I sort of get it why climate movement types want to just skip the whole mess, it gives you a headache
Many thanks for this interesting post as well as the preceding one. Just one quibble: My understanding from, for example, RPJ's Substack is that there is not actually any indication that tropical cyclones are getting more intense. Can that statement be consistent with the claim in your article ("monster storms")?
thx for this! I've been thinking about it. Roger Pielke Jr. is a treasure, and I'm a bit scared to take him on directly, but on this, I do think that he's...not wrong, exactly. It's just that he's right in such a narrow, technical, arcane way it's almost worse than being wrong.
I'll write more about it soon.
One nice thing about having a tiny little nascent reader community is that I can reply to each comment, and I'm glad to take direction about what to write next from you. My comments section is my commissioning editor!
Thanks for your reply. Having worked in shipping I’m well aware of the IMO regulations to reduce GHG emissions. Do you have sources for the radiative forcing data and its effects? FWIW the IMO continues to press the industry to continue lowering emissions. Ocean warming has numerous inputs (loss of reflective surfaces [ice], altered ocean currents, and certainly human activity. I’m curious about the contribution from reduction of ocean vessel GHG.
Human activities affect the Earth’s climate through modifying the composition of the atmosphere, which then creates radiative forcing that drives climate change. The warming effect of anthropogenic greenhouse gases has been partially balanced by the cooling effect of anthropogenic aerosols. In 2020, fuel regulations abruptly reduced the emission of sulfur dioxide from international shipping by about 80% and created an inadvertent geoengineering termination shock with global impact. Here we estimate the regulation leads to a radiative forcing of +0.2 (+/- 0.11)Wm−2 averaged over the global ocean. The amount of radiative forcing could lead to a doubling (or more) of the warming rate in the 2020 s compared with the rate since 1980 with strong spatiotemporal heterogeneity. The warming effect is consistent with the recent observed strong warming in 2023 and expected to make the 2020 s anomalously warm. The forcing is equivalent in magnitude to 80% of the measured increase in planetary heat uptake since 2020. The radiative forcing also has strong hemispheric contrast, which has important implications for precipitation pattern changes.
Yet again, I learned something new today. Two good articles in a row is frankly a better average than many sources I read. You're off to a very encouraging start. Thank you.
It makes me wonder if much of the warming of the last 50 years is due to reduced air pollution. We burn much less coal in the northern hemisphere than we once did.
It's a fascinating topic. Nobody writes about it.
Of course they don’t. Desired policies are not allowed to have undesirable side effects, even if most people would agree that the trade offs are worth it.
Interesting article, well reasoned by Quico (as always). There is just one thing I don't understand. When I look at the satellite picture of the ship trails, it reminds me very much of airplane condensation trails. There have been numerous articles in the press over the last couple years on the WARMING effect of contrails. Why is the effect of these ships tracks the opposite, cooling instead of warming?
Edit:
Just found my answer in the following article:
https://www.imperial.ac.uk/news/242017/clouds-created-aircraft-have-bigger-impact/
In a nutshell:
Ships produce a lot of aerosols but typically emit them low in the atmosphere – this changes clouds near to the Earth’s surface, making them brighter and creating a cooling effect.
Clouds formed from aviation are high up (10km up in the troposphere), and are very cold, making them good at stopping heat leaving the Earth and keeping it warm.
Not an easy story to sell to the public...
Clouds in general are a science communications shit show!! There are like 20 different hypothesized ways an aerosol can affect a cloud, the details change depending on weather conditions, season, altitude, it’s a nightmare. I mean I sort of get it why climate movement types want to just skip the whole mess, it gives you a headache
Many thanks for this interesting post as well as the preceding one. Just one quibble: My understanding from, for example, RPJ's Substack is that there is not actually any indication that tropical cyclones are getting more intense. Can that statement be consistent with the claim in your article ("monster storms")?
thx for this! I've been thinking about it. Roger Pielke Jr. is a treasure, and I'm a bit scared to take him on directly, but on this, I do think that he's...not wrong, exactly. It's just that he's right in such a narrow, technical, arcane way it's almost worse than being wrong.
I'll write more about it soon.
One nice thing about having a tiny little nascent reader community is that I can reply to each comment, and I'm glad to take direction about what to write next from you. My comments section is my commissioning editor!
Many thanks for your reply and for replying so quickly! I look forward to reading more about this!
Thanks for your reply. Having worked in shipping I’m well aware of the IMO regulations to reduce GHG emissions. Do you have sources for the radiative forcing data and its effects? FWIW the IMO continues to press the industry to continue lowering emissions. Ocean warming has numerous inputs (loss of reflective surfaces [ice], altered ocean currents, and certainly human activity. I’m curious about the contribution from reduction of ocean vessel GHG.
Research in this is ongoing, but: https://www.nature.com/articles/s43247-024-01442-3
Thanks, will review.
So the climate went “haywire” from this single cause?
Human activities affect the Earth’s climate through modifying the composition of the atmosphere, which then creates radiative forcing that drives climate change. The warming effect of anthropogenic greenhouse gases has been partially balanced by the cooling effect of anthropogenic aerosols. In 2020, fuel regulations abruptly reduced the emission of sulfur dioxide from international shipping by about 80% and created an inadvertent geoengineering termination shock with global impact. Here we estimate the regulation leads to a radiative forcing of +0.2 (+/- 0.11)Wm−2 averaged over the global ocean. The amount of radiative forcing could lead to a doubling (or more) of the warming rate in the 2020 s compared with the rate since 1980 with strong spatiotemporal heterogeneity. The warming effect is consistent with the recent observed strong warming in 2023 and expected to make the 2020 s anomalously warm. The forcing is equivalent in magnitude to 80% of the measured increase in planetary heat uptake since 2020. The radiative forcing also has strong hemispheric contrast, which has important implications for precipitation pattern changes.
Yet again, I learned something new today. Two good articles in a row is frankly a better average than many sources I read. You're off to a very encouraging start. Thank you.
thx! tell your friends!