For the past nine months, mean land and sea surface temperatures have overshot previous records each month by up to 0.2 °C — a huge margin at the planetary scale. A general warming trend is expected because of rising greenhouse-gas emissions, but this sudden heat spike greatly exceeds predictions made by statistical climate models that rely on past observations. Many reasons for this discrepancy have been proposed but, as yet, no combination of them has been able to reconcile our theories with what has happened. ... There is one more factor that could be playing a part. In 2020, new regulations required the shipping industry to use cleaner fuels that reduce sulfur emissions. Sulfur compounds in the atmosphere are reflective and influence several properties of clouds, thereby having an overall cooling effect. Preliminary estimates of the impact of these rules show a negligible effect on global mean temperatures — a change of only a few hundredths of a degree. But reliable assessments of aerosol emissions rely on networks of mostly volunteer-driven efforts, and it could be a year or more before the full data from 2023 are available. https://www.nature.com/articles/d41586-024-00816-z There have been volcanic eruptions in Iceland which might be a factor. But satellite data indicates that there has been a reduction in "ship tracks", the low clouds that form following ships. Whether and how much reduction in higher altitude sulfur aerosols has occurred is not known. It's not clear why ships were required to use low sulfur fuel, since most of the emissions would have been over open ocean and would not cause acid rain over land. Sulfur is not necessarily bad - after power plants in Europe were required to scrub sulfur, growers of cruciferous vegetables had to start using sulfur fertilizers.
So I guess what this is saying is that the climate change ninnies really don't know what the heck they're talking about. Shoot, I could have told them that.
