downwithtyranny | It may be a see-saw course, but it's riding an uphill train.
A bit ago I wrote, regarding climate and tipping points:
A bit ago I wrote, regarding climate and tipping points:
The concept of "tipping point" — a change beyond which there's no turning back — comes up a lot in climate discussions. An obvious tipping point involves polar ice. If the earth keeps warming — both in the atmosphere and in the ocean — at some point a full and permanent melt of Arctic and Antarctic ice is inevitable. Permanent ice first started forming in the Antarctic about 35 million years ago, thanks to global cooling which crossed a tipping point for ice formation. That's not very long ago. During the 200 million years before that, the earth was too warm for permanent ice to form, at least as far as we know.
We're now going the other direction, rewarming the earth, and permanent ice is increasingly disappearing, as you'd expect. At some point, permanent ice will be gone. At some point before that, its loss will be inevitable. Like the passengers in the car above, its end may not have come — yet — but there's no turning back....
I think the American Southwest is beyond a tipping point for available fresh water. I've written several times — for example, here — that California and the Southwest have passed "peak water," that the most water available to the region is what's available now. We can mitigate the severity of decline in supply (i.e., arrest the decline at a less-bad place by arresting its cause), and we can adapt to whatever consequences can't be mitigated.
But we can no longer go back to plentiful fresh water from the Colorado River watershed. That day is gone, and in fact, I suspect most in the region know it, even though it's not yet reflected in real estate prices.
Two of the three takeaways from the above paragraphs are these:
"California and the Southwest have passed 'peak water'" and "most in the
region know it." (The third takeaway from the above is discussed at the
end of this piece.)
"For the first time in 120 years, winter average minimum temperature in the Sierra Nevada was above freezing"
My comment, that "most in the region know it," is anecdotal. What you're about to read below isn't. Hunter Cutting, writing at Huffington Post, notes (my emphasis):
"For the first time in 120 years, winter average minimum temperature in the Sierra Nevada was above freezing"
My comment, that "most in the region know it," is anecdotal. What you're about to read below isn't. Hunter Cutting, writing at Huffington Post, notes (my emphasis):
With Californians crossing their fingers in hopes of a super El Niño to help end the state's historic drought, California's water agency just delivered some startling news: for the first time in 120 years of record keeping, the winter average minimum temperature in the Sierra Nevada was above freezing. And across the state, the last 12 months were the warmest on record. This explains why the Sierra Nevada snow pack that provides nearly 30% of the state's water stood at its lowest level in at least 500 years this last winter despite precipitation levels that, while low, still came in above recent record lows. The few winter storms of the past two years were warmer than average and tended to produce rain, not snow. And what snow fell melted away almost immediately.
Thresholds matter when it comes to climate change. A small increase in temperature can have a huge impact on natural systems and human infrastructure designed to cope with current weather patterns and extremes. Only a few inches of extra rain can top a levee protecting against flood. Only a degree of warming can be the difference between ice-up and navigable water, between snow pack and bare ground.
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