My initial impression of a future world with runaway Global Warming was one of deserts, droughts and being really thirsty. From what I have recently learned from reading some information provided by Paul Durack and others in Science magazine April 2012, there will actually be more rain as the temperature increases. I suppose if I had taken a little time to think about it I would have reached the same conclusion. The warmer the temperature is, the more evaporation there will be, which means an increase in the water cycle.
I am not saying I fully support all the claims of the coming disasters of Global Warming (that is for another blog), but I am interested in the concept of the possible acceleration of the water cycle. Mr. Durack estimates that the water cycle could undergo as much as a 24% increase if there is a 3° C average (5.4°F) temperature increase by the end of the century as some have predicted. The problem is, and always has been, that the evaporated water is not equally distributed around the surface area of the globe. As the water cycle accelerates dryer regions could get drier and wetter regions could get a lot wetter. Overall, there will be more fresh (non-salt) water falling from the sky than today.
So, why are we always hearing that we are running out of fresh water? Because we are. We can’t harvest all of it. Much of it just falls back into the ocean (77%) and the rest quickly runs off as surface water, returning to the ocean, in some cases, after flooding low lying areas. The scientific challenge is to think of ways to improve our “catch and hold” methods. Giant floating tankers with pipelines to land based reservoirs? More dams on land? Large underground storage tunnels? And of course, any land storage methods of holding water would also need some ingenious methods of reducing their evaporation losses.
These are all great engineering puzzles….maybe we can ask Siri how to fix it?
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