In 2020 the fuel sulphur limit in international shipping was reduced from 3.5 to 0.5 wt%. Three adaptive measures dominate: (i) increased exhaust gas cleaning in the maritime industry enabling continued use of high-sulphur fuel oil, (ii) increased refining output ratio of low-sulphur fuels, and iii) increased use of blended fuels. As (i) and (ii) are insufficient to comply with the new demand, refiners will resort to (iii), which requires increased crude oil throughput. Extracted crude oil will typically oxidize completely over longer time periods, so increased crude oil throughput is synonymous with increased CO2 emissions of up to 323 Mton in 2020, corresponding to similar to 1% of the total global CO2 emissions from fossil fuels. Transferring demand from low-value to high-value oil products cause indirect CO2 emissions, and vice versa. CO2 emissions can be mitigated by prioritizing demand reduction according to oil product value starting with the most valuable products.