4 ms·

> The idea that we'd eclipse the sun to control the climate is just one of the dumbest scifi nerd fantasies I've ever heard. Except we basically already did it

> The idea that we'd eclipse the sun to control the climate is just one of the dumbest scifi nerd fantasies I've ever heard. Except we basically already did it, just unintentionally. A primary hypothesized reason for the literally-off-the-charts heat of the past 15 months or so is that regulations that cleaned up the amount of sunlight-reflecting aerosols in container ship fuel was having the effect of letting more sunlight reach Earth; the idea is that the aerosols had previously been limiting the amount of global warming that would have shown up earlier. My point is that while geoengineering does sound pretty crazy at first, it feels less crazy once you realize we've already been doing geoengineering on a massive, global scale.

mynameisvlad 3y ago
Who, exactly, is hypothesizing this? Because I couldn’t find any reference to such a hypothesis.
- hn_throwaway_99 3y ago
  There is tons of research if you search for "low sulphur shipping rules", e.g. https://www.eceee.org/all-news/news/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.eceee.org/all-news/news/analysis-how-low-sulphur...
  - swatcoder 3y ago
    Being more reserved about phrases like "tons of research" and "primary hypothesized reason" when sharing one study that proposes a small but unexpected contributing factor and some intra-industry coverage of that study would have saved you some downvotes and conflict here. It's a really fascinating phenomenon and I'm glad you shared it, but the researchers likely wouldn't stand by your phrasing and if you trace the stories and search results, you can see that it's really all just reporting about the same single bit of research from those researchers. So those pushing back on your own claims about it here have a point.
  - mynameisvlad 3y ago
    The linked article (notably not a paper nor reviewed) states: > Taking the high end of the range of estimates of radiative forcing could result in up to 0.18C additional warming by 2030 and 0.25C additional warming by 2050, though most studies have found lower forcing estimates than this. https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.carbonbrief.org/analysis-how-low-sulphur-shippin... That’s nowhere near enough to back your previous claim. In fact, that entire article looks at decade-long scales.
alehlopeh 3y ago
Yes that’s definitely the preeminent primary hypothesized reason. /s
- hn_throwaway_99 3y ago
  Yes, it is, and your snarky response misses the point and misunderstands my comment. Obviously CO2 and other greenhouse gas emissions are what's driving climate change. But climate scientists have been surprised by the recent (like post-pandemic) big spike in heat, especially in the North Atlantic, and they hypothesize that low sulphur shipping rules that went into effect in 2020 reduced the global warming "masking effect" that these aerosols previously had: https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.carbonbrief.org/analysis-how-low-sulphur-shippin...
  - silverquiet 3y ago
    Your own source contradicts you. > Given that there will be a lagged response from the climate to the shift to low-sulphur marine fuel, it is reasonable to expect less than half of the warming resulting from the 2020 regulations to have materialised by 2023, likely only in the hundredths of a degree globally. > This is unlikely to be sufficient to explain the spike in global sea surface temperature in recent weeks, which is around 0.2C above the prior record for this time of year.
  - rad_gruchalski 3y ago
    > and they hypothesize
silverquiet 3y ago
> A primary hypothesized reason for the literally-off-the-charts heat of the past 15 months or so is that regulations that cleaned up the amount of sunlight-reflecting aerosols in container ship fuel was having the effect of letting more sunlight reach Earth; the idea is that the aerosols had previously been limiting the amount of global warming that would have shown up earlier. I see this repeated a lot on HN, but it appears to be incorrect. It seems that climate scientists are aware of aerosols and can model them, but 2023 is still a baffling outlier. > These include continued accumulation of greenhouse gases, the evolution of El Niña and La Niña, and the 11-year solar cycle. It also includes two new factors that emerged during the decade: the 2022 eruption of the Hunga Tonga volcano and the 2020 phase-out of sulphur in marine fuels. Both of these are estimated to have relatively modest effects at present – less than 0.05C each – but with large scientific uncertainties. > Similarly, the phase-out of sulphur in marine fuels occurred in 2020. If it had a large climate impact, it would show up in 2021 and 2022 rather than suddenly affecting the record in 2023. While it definitely has had a climate impact – alongside the broader reduction in aerosol emissions over the past three decades – the timing suggests that its likely not the primary driver of 2023 extremes. https://www.theclimatebrink.com/p/2023s-unexpected-and-unexplained https://www.theclimatebrink.com/p/2023s-unexpected-and-unexp...
- PopAlongKid 3y ago
  s/El Niña/El Niño/

mynameisvlad 3y ago

Who, exactly, is hypothesizing this? Because I couldn’t find any reference to such a hypothesis.

hn_throwaway_99 3y ago
There is tons of research if you search for "low sulphur shipping rules", e.g. https://www.eceee.org/all-news/news/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.eceee.org/all-news/news/analysis-how-low-sulphur...
- swatcoder 3y ago
  Being more reserved about phrases like "tons of research" and "primary hypothesized reason" when sharing one study that proposes a small but unexpected contributing factor and some intra-industry coverage of that study would have saved you some downvotes and conflict here. It's a really fascinating phenomenon and I'm glad you shared it, but the researchers likely wouldn't stand by your phrasing and if you trace the stories and search results, you can see that it's really all just reporting about the same single bit of research from those researchers. So those pushing back on your own claims about it here have a point.
- mynameisvlad 3y ago
  The linked article (notably not a paper nor reviewed) states: > Taking the high end of the range of estimates of radiative forcing could result in up to 0.18C additional warming by 2030 and 0.25C additional warming by 2050, though most studies have found lower forcing estimates than this. https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.carbonbrief.org/analysis-how-low-sulphur-shippin... That’s nowhere near enough to back your previous claim. In fact, that entire article looks at decade-long scales.

alehlopeh 3y ago

Yes that’s definitely the preeminent primary hypothesized reason. /s

hn_throwaway_99 3y ago
Yes, it is, and your snarky response misses the point and misunderstands my comment. Obviously CO2 and other greenhouse gas emissions are what's driving climate change. But climate scientists have been surprised by the recent (like post-pandemic) big spike in heat, especially in the North Atlantic, and they hypothesize that low sulphur shipping rules that went into effect in 2020 reduced the global warming "masking effect" that these aerosols previously had: https://www.carbonbrief.org/analysis-how-low-sulphur-shipping-rules-are-affecting-global-warming/ https://www.carbonbrief.org/analysis-how-low-sulphur-shippin...
- silverquiet 3y ago
  Your own source contradicts you. > Given that there will be a lagged response from the climate to the shift to low-sulphur marine fuel, it is reasonable to expect less than half of the warming resulting from the 2020 regulations to have materialised by 2023, likely only in the hundredths of a degree globally. > This is unlikely to be sufficient to explain the spike in global sea surface temperature in recent weeks, which is around 0.2C above the prior record for this time of year.
- rad_gruchalski 3y ago
  > and they hypothesize

silverquiet 3y ago

> A primary hypothesized reason for the literally-off-the-charts heat of the past 15 months or so is that regulations that cleaned up the amount of sunlight-reflecting aerosols in container ship fuel was having the effect of letting more sunlight reach Earth; the idea is that the aerosols had previously been limiting the amount of global warming that would have shown up earlier. I see this repeated a lot on HN, but it appears to be incorrect. It seems that climate scientists are aware of aerosols and can model them, but 2023 is still a baffling outlier. > These include continued accumulation of greenhouse gases, the evolution of El Niña and La Niña, and the 11-year solar cycle. It also includes two new factors that emerged during the decade: the 2022 eruption of the Hunga Tonga volcano and the 2020 phase-out of sulphur in marine fuels. Both of these are estimated to have relatively modest effects at present – less than 0.05C each – but with large scientific uncertainties. > Similarly, the phase-out of sulphur in marine fuels occurred in 2020. If it had a large climate impact, it would show up in 2021 and 2022 rather than suddenly affecting the record in 2023. While it definitely has had a climate impact – alongside the broader reduction in aerosol emissions over the past three decades – the timing suggests that its likely not the primary driver of 2023 extremes. https://www.theclimatebrink.com/p/2023s-unexpected-and-unexplained https://www.theclimatebrink.com/p/2023s-unexpected-and-unexp...

PopAlongKid 3y ago
s/El Niña/El Niño/