No CO₂ from hard_coal in v2024_07_08 international shipping?

[LeonSimons]

Looking at the international shipping emissions of v2024_07_08, I noticed that CO₂ increased before SO₂ did:

This doesn't seem to be accurate? Looking CO₂ and SO₂ by Fuel shows no CO₂ emissions from hard coal, but it does show SO₂ emissions:

[ssmithClimate]

Thanks @LeonSimons for the careful look, that doesn't sound right. We'll get that fixed.

[LeonSimons]

Thank you for the rapid response, Steven.

[jkikstra]

Looks like this has been updated (& resolved?)

ceds-update-shipping-so2-co2.pdf

[ssmithClimate]

Yes resolved. (Just not released publicly yet since we're squashing bugs you and others may find.)

[LeonSimons]

Thank you for sharing Jarmo.

I notice the update has lower shipping SO₂ emissions than the previous version?

Could you elaborate on this Steven?

On May 1st 2025 a new Emission Control Area will come into effect over the Mediterranean.
This will reduce regional sulphur emissions further. Also depending on past and future scrubber adoption, which reduces emissions by up to 98%.

[ssmithClimate]

Yes, in 2020 and after our new emission estimates are lower. This is mostly due an updated calculation for SO2 scrubber use 2020 and after, which lowered emissions. Instead of just using the fraction of ships with scrubbers, we adjusted this to account for the observation that the ships that use the most fuel are more likely to use scrubbers to come into compliance (Hermansson etal (2024), Strong economic incentives of ship scrubbers promoting pollution.) This ups the overall compliance rate significantly. (All still uncertain, and there's a lot of papers out there - as you probably know - discussing how to assure compliance. So hopefully there will be better data at some point. So we do the best we can with what we have.)

FYI - we also updated our gridding proxy for shipping to use CAMS shipping, which has more regionally specific and annual detail over recent time than what we used before. I'm sure the CAMS shipping group is planning to incorporate changes such as you mention above into their updates.

[LeonSimons]

Thank you Steve,

From Greg Miller, I learned that "Lloyds Seasearcher data has not been updated for newly delivered ships with scrubber installations and retrofits for over two years". For this article, he used Clarksons data instead (see PDF attached): https://www.lloydslist.com/LL1152606/Scrubber-trend-not-over-yet-Uptake-still-rising-despite-tighter-fuel-spread

Ships using scrubbers will likely show even lower emissions than ships using VLSFO. Actual sulphur emissions will depend on total fuel use per ship, as you mentioned. Would be interesting to see those calculations in detail, but I guess it's hard to break it all down.

Scrubber trend not over yet_ Uptake still rising despite tighter fuel spread __ Lloyd's List.pdf