This is an interesting article about the potential for using Liquid Natural Gas (LNG) in maritime transport instead of (or alongside) traditional bunker fuel. The latter is a highly polluting low-grade, low-cost fuel which produces, among other things, high sulphur emissions. These emissions will be getting a much tighter cap from 2015, so a lot of work is being done into alternative fuels. 

This caught my eye because I heard this new cap being used recently as a good example of unintentional geoengineering. Sulphur emissions lead to higher concentrations of aerosols (particulate matter) in the atmosphere, which in turn reduces the amount of sunlight reaching the Earth’s surface. The drastic reduction in sulphur emissions from shipping will reduce this “dimming” effect (explained here), with a concomitant increase in surface temperature. I can’t remember what this anticipated increase was, but it was roughly equivalent to front-loading several decades of the predicted warming due to anthropogenic carbon emissions. 

The point was that as much as people may dislike the idea of geoengineering, it has been progressing on a massive (albeit unintended) scale for a long time and should be debated in this context.