I'm attempting to get some rough idea of the increase in precipitation for different temperature rises.

My method at present is very rough, look at the temperature rise at the end of phase 3 as against end of phase 2 for stable runs, and round it to the nearest 0.5C. Then for precipitation do the same rounding to the nearest 0.25mm/day. As these have been done by eye they are fairly inaccurate.

My results are (after 57 results):

Temp rise precipitation rise number
1.5            0.067            3
2.0            0.088            2
2.5            0.118            10
3.0            0.159            11
3.5            0.181            9
4.0            0.181            4
4.5            0.200            9
5.0            0.200            2
5.5            0.200            2
6.0            0.263            2
6.5            0.250            1
7.0            0.275            1
7.0            0.275            1


Up to a temperature rise of about 3.5C the precipitation seems to increase linearly, after that it seems to fall of and settle at somewhere between 0.25 and 0.30mm/day but there are not yet enough results to make this a robust conclusion.

This result seems to go against what I've read which says that precipitation increases linearly with temperature rise. It also could have a bearing on whether the high sensitivity models are realistic or not.

Most worryingly, it may be that high sensitive parameter sets or high temperature rises have lower precipitation than predicted. If this is so then larger areas of the world will go into drought conditions.

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<a href="http://www.boincforum.info/boinc/">boinc forum</a> and <a href="http://www.uk4cp.co.uk/">United Kindom</a> team, my climate change <a href="http://www.livejournal.com/users/mike_atkinson/">blog</a>.