Climate Creep and Rotten Ice

I hear that the entire Mekong Delta is likely to flood at high tide by 2050.

And parts of the Nile Delta. And a broad swath of Bangladesh. And the U.S. Gulf of Mexico coastline.

Farmers could still raise salt-resistant crops on a river delta, but they would have to commute every day, just as the Hopi Pueblo people do, running back from their fields to their mesa top dwellings before sunset. Just imagine New Orleans with the convention hotels still operating most of the time, but where all workers have a high-speed, wi-fi-enabled commute back to their dwellings on higher grounds. Over time, new cities will develop up there, mining the ruins at low tide for building materials.

In between, there might be a neo-Venice Era, with gondola taxis between urban islands guarded by coffer dams.

Residents still might want to flee, should bankrupt cities no longer provide police and fire, should utilities fail, gangs take over, and so forth. Or residents may simply flee the increasing heat and humidity, especially if electricity for air conditioning becomes unreliable.

Some residents will move out of state, just to avoid taxation for repairing the damage.

That’s certainly a worry in Florida where state taxpayers guarantee insurance companies against excessive losses. Major nationwide insurance companies stopped writing new policies in coastal Florida twenty years ago. But without insurance, buyers cannot get a mortgage, and thus most condo sales would have frozen. And so the whole state’s taxpayers are on the hook, no matter how far inland they reside.

But it’s not just coastlines that are being slowly invaded. The tropics have been expanding to the north (and the south), in turn pushing the desert dry bands up into the temperate zones, as in southern California and the Mediterranean. The dry zone in central Australia is pushing south, threatening to move their sliver of westerly winds (delivering ocean moisture) farther south, off the edge of South Australia. Perth is 32° from the equator, the same as San Diego.

That desert-zone creep is reversible if we cool ourselves off; sea level, however, would continue to rise because draining meltwater from the surface of an ice sheet down a crack has weakened the base of some ice sheets, allowing them to shear, the upper layers continuing downhill. It’s a familiar consideration in evaluating avalanche danger; any basic mountaineering course teaches it.

Rotten ice. That could have been prevented if we had acted earlier.

The creeps are the part of the climate problem that climate models have been forecasting since 1968. Modeling has come a long way in a half-century, but it is only beginning to tackle the dynamics, such as the jet stream resonances that can lock a loop in place. With no eastward drift of the jet-stream loops, the trapped lows keep producing floods. The cloudless highs, when stalled, prolong heat waves and fire weather, sometimes for a few weeks. The loop turnarounds produce severe windstorms that may continue to batter a city until the jet stream’s ground path finally drifts eastward again.

What’s going to kill people in great numbers, long before heat stroke gets around to it, is disorganization: losing societal stuff, like police and fire departments, judges to settle disputes peacefully while enforcing contracts so that lenders will still advance loans to farmers, with which to buy seeds to plant.

Are farmers still going to be able to get in a second crop during the growing season?

Indonesia is already having trouble with their third crop, just because the rainfall timing has shifted a month with overheating.

Extreme weather makes the second harvest unreliable. We ought to be using the second crop to build up a stockpile for lean years.

But what worries you more, I see, are the sudden shifts in extreme weather. Leaps, rather than Creeps?

Yes, shifts in five types of extreme weather show that the climate has become unstable, apt to produce surprises not included in those gradual-only 1.5°C forecasts. And the only way I can see to back out of the danger zone for abrupt climate shifts is to cool back down in a hurry. I’ll save that for next time.