It's about water

Final installment of my rant about global warming, for now, is to raise the issues I heard raised by Larry Dale, most recently as mentioned a couple of posts ago in a visit he and his co-researchers at the Climate Change Center made to a group of us at PG&E. The relationships of gasoline, coal and natural gas to global warming are obvious -- they're all fossil fuels (refined or unrefined), and the fact that they're in some ways substitutable for each other raises complicated and interesting questions about trying to limit their use. But water?

Well, from my perspective working at PG&E, water is a renewable generation source, again substitutable for other energy sources such as fossil fuels. But what Larry Dale's research has been about, the changes in how water will be "delivered" to the state of California by our friendly neighborhood climate, affects the use of water for consumption as much as it does the use of water for electricity production. What we think we know so far is that:

1) Global warming will reduce California's ability to store its annual water supply in the Sierra snow pack, effectively eliminating a huge state reservoir of all the man-made ones.

2) California may get almost the same amount of rain, on average per year, fifty or a hundred years from now as it does now. But the characteristics of the rainfall patterns may be drastically different: the general picture is of rains starting earlier and ending earlier, on average, making the storage of water to serve the period of its greatest demand, the dry summer, more difficult. Also, weather may be more volatile and more rain may come in the form of "extreme" events like larger storms.

3) Because of the still enormous supplies of water underground in the state, California is blessed or cursed with the possibility of almost directly substituting energy use for natural weather patterns in maintaining its water supplies. This doesn't mean our droughts haven't been real, as I take it, but that at a high enough cost in energy our essential needs could be met even under future scenarios that deliver a lot less water from the mountains to the farms and cities.