I think you're mistaken that passenger cars are the smaller part. I'm struggling to find a clear source but pg 45 of this [1] shows passenger cars as 50% of to

I think you're mistaken that passenger cars are the smaller part. I'm struggling to find a clear source but pg 45 of this [1] shows passenger cars as 50% of total transportation energy (including road freight and shipping, I think) and page 35 projects passenger cars as 43%, compared to 8% for shipping, of CO2 emissions in 2050. You might be mixing up CO2 emissions with Sulfur emissions [2] [1] https://www.iea.org/publications/freepublications/publication/transport2009.pdf https://www.iea.org/publications/freepublications/publicatio... [2] https://www.quora.com/Is-it-true-that-the-15-biggest-ships-in-the-world-produce-more-pollution-than-all-the-cars https://www.quora.com/Is-it-true-that-the-15-biggest-ships-i...