Effect of a +1 degree temp. change on water supply?

Question

Does anyone have insight on how this impacts the water cycle, or a good reference? Where I live, warming causes summer drought because we lose the pack-ice on mountain tops that supply rivers during the dry summer. I guess what i'm looking for is projectons of things like additional # of "drought" days, or accelerated water loss in lakes, etc

Answer 1

There's no general answer to that question. Local condtions vary so much. For example, a change in the prevailing winds can affect precipitation and cause droughts or floods. There are some pretty warm places that are very wet.

Answer 2

Each one degree rise in the temperature of the oceans is the equivalent to the energy yield of 1.3 BILLION (yes, with a "B") one MegaTon atom bombs.  That energy is  expressed as more extreme weather.

The localized effects of Global Warming will depend on more than just that excess energy, though.  For example, British Columbia, Oregon, Washington and northern California have had a LOT of rain.  That is a normal effect of storm systems passing over mountains.  But if the majority of the water falls on the Pacific side of the Great Divide rather than the Atlantic side, no prairie provinces or mid western "bread basket" states get water for crops from that intense rainfall.  

And rain isn't stored in the mountains until spring.

You hit the nail on the head talking about the loss of the potential energy and water supply due to more rainfall and less snowfall in the mountains.  Hydroelectric operators are going to have problems in the future.

As for water loss in lakes.  Lake Superior lost about 20 million cubic meters of water last August during a single storm.  

In areas which do not normally get a lot of rainfall it is hard to tell; more water in the atmosphere generally means more rain, but as stated above more things affect rainfall than just the temperature.  I suggest you check the Hanley (Hadley?) Center for Atmospheric Research or the CIAS supercomputer for more accurate projections.

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Answer 3

If it is 1 degree higher, it will melt ice faster, and evaporate faster.