# Water formation from fossil fuels and sea level rise - maths check please **URL:** \ **Category:** Factual Questions\ **Created:** [May 31, 2019, 10:54am UTC](https://boards.straightdope.com/t/water-formation-from-fossil-fuels-and-sea-level-rise-maths-check-please/834820 "2019-05-31T10:54:33Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [May 31, 2019, 10:54am UTC](https://boards.straightdope.com/t/water-formation-from-fossil-fuels-and-sea-level-rise-maths-check-please/834820/1 "2019-05-31T10:54:33Z")
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](https://iopscience.iop.org/article/10.1088/1748-9326/aa8390/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? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [May 31, 2019, 1:06pm UTC](https://boards.straightdope.com/t/water-formation-from-fossil-fuels-and-sea-level-rise-maths-check-please/834820/2 "2019-05-31T13:06:14Z")
> [@Quartz](#): > > 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](https://iopscience.iop.org/article/10.1088/1748-9326/aa8390/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”. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [May 31, 2019, 1:18pm UTC](https://boards.straightdope.com/t/water-formation-from-fossil-fuels-and-sea-level-rise-maths-check-please/834820/3 "2019-05-31T13:18:28Z")
> [@Quartz](#): > > 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? 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. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [May 31, 2019, 8:32pm UTC](https://boards.straightdope.com/t/water-formation-from-fossil-fuels-and-sea-level-rise-maths-check-please/834820/4 "2019-05-31T20:32:02Z")
The OP sure seems to be aware of that, given the use of words like “contributing to”, and clearly specifying “from this source”.