We are living yesterday's tomorrow...

Stay with me on this one. 

The consequences of actions taken in my father's time are reaching maturity - and not in a good way. And they presage the the results of my own decisions.


Example:  The Hoover Dam

Nobody loves to watch those History Channel pieces about building the Hoover Dam more than I. But demand for water has made it less an answer than a relic.

The promise of abundant water and power took the brakes off the growth of Los Angeles, San Diego and many other western cities; it encouraged farmers to complacently plant the most water-thirsty crops; and it gave us city dwellers the impression that we can water our lawns every day without worrying about waste and runoff.

Yet the world Hoover Dam made is now facing the era of limits. For decades California was able to use Colorado River water formally apportioned to Arizona and Nevada, because those states weren't developed enough to use their full allocations. That condition ended in the mid-1990s, at which point California had to give up nearly 20% of its Colorado River supply.

Thus far we've managed a "soft landing" from that shock by crafting intricate reallocations of water among the state's agricultural, urban and ecological interests. But the balancing act is only getting harder, as a long drought shrinks our water-supply cushion and population growth continues almost unabated. Up to now, solutions to our water needs have been worked out in a crisis atmosphere. In the future, they'll take place against a political background too.

In the Central Valley, farmers are already marching to demand the construction of more dams to provide more water for irrigation, as if one can just create abundance out of thin air. Environmentalists' efforts to discharge water from reservoirs to preserve riparian and marine habitats draw the ridicule of conservative television pundits. Private companies have moved into the water business, figuring that where there's scarcity there are profits. [More]

Now consider how temporary that drought could be.  My guess: not very. 

In fact, let's go the the "worsest" case of all.  This is the 5% probability of climate change and global warming. (Not for the squeamish)

There is a horrible paper in this week's Proceedings of the National Academy of Sciences (hat-tip Desdemona Despair), which looks at how the limits of human physiology interact with upper-range global warming scenarios.  The bottom line conclusion is that there is a small - of order 5% - risk of global warming creating a situation in which a large fraction of the planet was uninhabitable (in the sense that if you were outside for an extended period during the hottest days of the year, even in the shade with wet clothing, you would die).  To give you a feeling for the likely uninhabitable regions, it's the portions of the map above that are in the white or pink/purple color (above 35^oC wet bulb temperature on the scale).  As you can see, it includes most of the eastern US, much of inland Brazil and Latin America, tropical Africa, pretty much all of India, portions of northern China, and most of Australia.  Plenty to qualify as a "Risk to Global Civilization", I think.

 Some explanation is in order so I will borrow freely, with apologies.

More precisely, the wet bulb temperature being plotted here is the average annual high that extended for at least six hours, and the data is for 1999-2008.  So the filthy-hottest parts of the planet become clear - the tropics of course, with the inland Amazon and northern India worst, but the eastern US is not far behind, as also northern China and much of Australia.

So how high a wet bulb temperature can people tolerate?  The paper doesn't cite much experimental data (apparently the Nazi scientists missed this in their program) but what is known is that skin temperatures above 35^oC (which is 95^oF) are fatal for an extended period (your skin needs to be at least a few degrees cooler than your core temperature of 37^oC/98^oF so that heat can be conducted from the blood to the skin in order to shed metabolic heat).  So it's reasonable that if the wet bulb temperature is above this for an extended period (they take six hours) you won't be able to survive.  In fact, given that a human who needs to be outside probably won't be sitting in the shade with wet clothes and a big fan, the maximum survivable wet bulb temperature may actually be a degree or two lower.

At the moment, as the map above shows, nowhere on the planet gets up that high.  The highest is in the low thirties - pretty damn unpleasant, no doubt, and no-one is going to do a whole lot outside under those conditions, but not actually fatal for all but a small minority of folks (probably with other health conditions). [Same source]

OK, it's fair to howl derisively at the long shot this represents, but keep that 5% chance number in mind when you hear predictions about deficits, hunger, health care costs, etc.  If you use any 1-in-20 example to buttress your case, then this exercise is for you.

For my part, the fact this horrific outcome has a 5% chance, while a double-dip recession now is accorded a 12% chance and many of us have already taken that to heart means it is not a future we should discount out of hand, if only for relative probability consistency.

Back to the Hoover Dam.  The scenario outlined above certainly casts in doubt the future of water-intensive commodities like cotton in California.  If there is water for crops, it will be very high value produce, I would suggest.

Compare and contrast the above charts. I have, just like the maps of IL moving (climate-wise) to AR.

[More]

So let's say you are skeptical of these outcomes.  How about if the USGCRP is just half-right?

OK, make your own bet.  But I think the money is going to be made adapting to very high temps and rainfall here and desertification farther west.

Everybody gets to take a position on this one.