We were discussing oil the other day and it came up that the two products of combustion are CO2 and H2O - water - and we wondered how much that contributed to sea level rise.
So please check my maths.
I did some digging. Figure 1 in this PDF says that the worldwide production is 12 x 10^12 kg. or 12 x 10^9 tonnes. Now 1 tonne of water is 1 cubic metre (by definition) so we have 12 x 10^9 cubic metres of water produced.
The area of the Earth is 510 x 10^12 m2. 71% is water or 362 x 10^12 m2.
Therefore the sea level rise purely from water formation is the former divided by the latter. I get a figure of 1/30th of a mm - utterly inconsequential. Have I forgotten a conversion factor somewhere?
No, that looks right. That’s for just one year though, so the total for all fossil fuels might be a whole millimeter, but then you have to consider the injection of water into wells and for fracking … I think we can safely go with “Inconsequential for sea level change”.
I’m sure you’re quite aware that this “water formation” is completely unrelated to either of the two reasons why warming climate causes sea-level rise.