"Dear Wharfie,. The theory that more and deeper floods will result from CO2 at 400 ppm instead of 280 ppm and even more at 500ppm instead of 400 ppm is bung. "
No, your scientific knowledge is bunk, altho it's actually not the CO2 which directly increases rainfall. CO2 increases the temperature. Increased temperatures means increased water in the atmosphere; 7% more/ degree C, and temperatures are up by 1.5 degrees C from the pre-industrial Earth. That means heavier rain and snow when they fall, but it doesn't always mean they are gonna fall on you, which is why droughts are also getting worse.
==
" I wonder what a global vote would find to the question 'Would you like the average temperature to be up or down 1 degree Celsius?' I'd vote for up 5 degrees."
I suspect most climate refugees, whether from floods, fires, or drought, would vote for 1 degree cooler.
==
#67178
Lynas 6 degrees
From The Sunday Times March 11, 2007
What will climate change do to our planet?
BETWEEN FOUR AND FIVE DEGREES OF WARMING
We are looking now at an entirely different planet. Ice sheets have vanished from both poles; rainforests have burnt up and turned to desert; the dry and lifeless Alps resemble the High Atlas; rising seas are scouring deep into continental interiors. One temptation may be to shift populations from dry areas to the newly thawed regions of the far north, in Canada and Siberia. Even here, though, summers may be too hot for crops to be grown away from the coasts; and there is no guarantee that northern governments will admit southern refugees. Lynas recalls James Lovelock's suspicion that Siberia and Canada would be invaded by China and the US, each hammering another nail into humanity's coffin. "Any armed conflict, particularly involving nuclear weapons, would of course further increase the planetary surface area uninhabitable for humans."
When temperatures were at a similar level 55m years ago, following a very sudden burst of global warming in the early Eocene, alligators and other subtropical species were living high in the Arctic. What had caused the climate to flip? Suspicion rests on methane hydrate - "an ice-like combination of methane and water that forms under the intense cold and pressure of the deep sea", and which escapes with explosive force when tapped. Evidence of a submarine landslide off Florida, and of huge volcanic eruptions under the North Atlantic, raises the possibility of trapped methane - a greenhouse gas 20 times more potent than carbon dioxide - being released in a giant belch that, as Lynas puts it, "pushed global temperatures through the roof".
"Summer heatwaves scorched the vegetation out of continental Spain, leaving a desert terrain which was heavily eroded by winter rainstorms. Palm mangroves grew as far north as England and Belgium, and the Arctic Ocean was so warm that Mediterranean algae thrived. In short, it was a world much like the one we are heading into this century." Although the total amount of carbon in the atmosphere during the Paleocene-Eocene thermal maximum, or PETM, as scientists call it, was more than today's, the rate of increase in the 21st century may be 30 times faster. It may well be the fastest increase the world has ever seen - faster even than the episodes that caused catastrophic mass extinctions.
Globalism in the five-degree world will break down into something more like parochialism. Customers will have nothing to buy because producers will have nothing to sell. With no possibility of international aid, migrants will have to force their way into the few remaining habitable enclaves and fight for survival.
"Where no refuge is available," says Lynas, "civil war and a collapse into racial or communal conflict seems the likely outcome." Isolated survivalism, however, may be as impracticable as dialling for room service. "How many of us could really trap or kill enough game to feed a family? Even if large numbers of people did successfully manage to fan out into the countryside, wildlife populations would quickly dwindle under the pressure. Supporting a hunter-gatherer lifestyle takes 10 to 100 times the land per person that a settled agricultural community needs. A large-scale resort to survivalism would turn into a further disaster for biodiversity as hungry humans killed and ate anything that moved." Including, perhaps, each other. "Invaders," says Lynas, "do not take kindly to residents denying them food. History suggests that if a stockpile is discovered, the householder and his family may be tortured and killed. Look for comparison to the experience of present-day Somalia, Sudan or Burundi, where conflicts over scarce land and food are at the root of lingering tribal wars and state collapse."
Chance of avoiding five degrees of global warming: negligible if the rise reaches four degrees and releases trapped methane from the sea bed.
BETWEEN FIVE AND SIX DEGREES OF WARMING
Although warming on this scale lies within the IPCC's officially endorsed range of 21st-century possibilities, climate models have little to say about what Lynas, echoing Dante, describes as "the Sixth Circle of Hell". To see the most recent climatic lookalike, we have to turn the geological clock back between 144m and 65m years, to the Cretaceous, which ended with the extinction of the dinosaurs. There was an even closer fit at the end of the Permian, 251m years ago, when global temperatures rose by - yes - six degrees, and 95% of species were wiped out.
"That episode," says Lynas, "was the worst ever endured by life on Earth, the closest the planet has come to ending up a dead and desolate rock in space." On land, the only winners were fungi that flourished on dying trees and shrubs. At sea there were only losers. "Warm water is a killer. Less oxygen can dissolve, so conditions become stagnant and anoxic. Oxygen-breathing water-dwellers - all the higher forms of life from plankton to sharks - face suffocation. Warm water also expands, and sea levels rose by 20 metres." The resulting "super-hurricanes" hitting the coasts would have "triggered flash floods that no living thing could have survived".
There are aspects of the so-called "end-Permian extinction" that are unlikely to recur - most importantly, the vast volcanic eruption in Siberia that spread magma hundreds of metres thick over an area bigger than western Europe and shot billions of tonnes of CO² into the atmosphere. That is small comfort, however, for beneath the oceans, another monster stirred - the same that would bring a devastating end to the Palaeocene nearly 200m years later, and that still lies in wait today. Methane hydrate.
Lynas describes what happens when warming water releases pent-up gas from the sea bed. "First, a small disturbance drives a gas-saturated parcel of water upwards. As it rises, bubbles begin to appear, as dissolved gas fizzles out with reducing pressure - just as a bottle of lemonade overflows if the top is taken off too quickly. These bubbles make the parcel of water still more buoyant, accelerating its rise through the water. As it surges upwards, reaching explosive force, it drags surrounding water ?up with it. At the surface, water is shot hundreds of metres into the air as the released gas blasts into the atmosphere. Shockwaves propagate outwards in all directions, triggering more eruptions nearby."
The eruption is more than just another positive feedback in the quickening process of global warming. Unlike CO², methane is flammable. "Even in air-methane concentrations as low as 5%," says Lynas, "the mixture could ignite from lightning or some other spark and send fireballs tearing across the sky." The effect would be much like that of the fuel-air explosives used by the US and Russian armies - so-called "vacuum bombs" that ignite fuel droplets above a target. According to the CIA, "Those near the ignition point are obliterated. Those at the fringes are likely to suffer many internal injuries, including burst eardrums, severe concussion, ruptured lungs and internal organs, and possibly blindness." Such tactical weapons, however, are squibs when set against methane-air clouds from oceanic eruptions. Scientists calculate that they could "destroy terrestrial life almost entirely" (251m years ago, only one large land animal, the pig-like lystrosaurus, survived). It has been estimated that a large eruption in future could release energy equivalent to 108 megatonnes of TNT - 100,000 times more than the world's entire stockpile of nuclear weapons. Not even Lynas, for all his scientific propriety, can avoid the Hollywood ending. "It is not too difficult to imagine the ultimate nightmare, with oceanic methane eruptions near large population centres wiping out billions of people - perhaps in days. Imagine a 'fuel-air explosive' fireball racing towards a city - London, say, or Tokyo - the blast wave spreading out from the explosive centre with the speed and force of an atomic bomb. Buildings are flattened, people are incinerated where they stand, or left blind and deaf by the force of the explosion. Mix Hiroshima with post-Katrina New Orleans to get some idea of what such a catastrophe might look like: burnt survivors battling over food, wandering far and wide from empty cities."
Then would come hydrogen sulphide from the stagnant oceans. "It would be a silent killer: imagine the scene at Bhopal following the Union Carbide gas release in 1984, replayed first at coastal settlements, then continental interiors across the world. At the same time, as the ozone layer came under assault, we would feel the sun's rays burning into our skin, and the first cell mutations would be triggering outbreaks of cancer among anyone who survived. Dante's hell was a place of judgment, where humanity was for ever punished for its sins. With all the remaining forests burning, and the corpses of people, livestock and wildlife piling up in every continent, the six-degree world would be a harsh penalty indeed for the mundane crime of burning fossil energy."
RED ALERT
If global warming continues at the current rate, we could be facing extinction. So what exactly is going to happen as the Earth heats up? Here is a degree-by-degree guide
1c Increase
Ice-free sea absorbs ?more heat and accelerates global warming; fresh water lost from a third of the world's surface; low-lying coastlines flooded
2c Increase
Europeans dying of heatstroke; forests ravaged by fire; stressed plants beginning to emit carbon rather than absorbing it; a third of all species face extinction
3c Increase
Carbon release from vegetation and soils ?speeds global warming; death of the Amazon rainforest; super-hurricanes hit coastal cities; starvation in Africa
4c Increase
Runaway thaw of permafrost makes global warming unstoppable; much of Britain made uninhabitable by severe flooding; Mediterranean region abandoned
5c Increase
Methane from ocean floor accelerates global warming; ice gone from both poles; humans migrate in search of food and try vainly to live like animals off the land
6c Increase
Life on Earth ends with apocalyptic storms, flash floods, hydrogen sulphide gas and methane fireballs racing across the globe with the power of atomic bombs; only fungi survive.
==
"Regarding crops, they do much better with 1000 ppm CO2 than the Tragedy of the Commons starvation level of 280 ppm"
Crops were growing just fine in the pre-industrial era, and most of the increase since then has been because of the Green Revolution, not an increase in CO2.
Plants in the controlled environment of a biology lab might grow better with 1000 PPM, but, in real life, farmers can't control the temperature and water. Despite the "wonderful 400 PPM CO2" in the skies over my state, frmers were devastated, despite being plugged in to probably the best aqueduct system since the collapse of Rome.
Policy Brief: Drought and Groundwater Sustainability in ...
Drought is costly to the state, and especially to its large agricultural sector. Over a billion dollars of economic output and thousands of jobs were lost in both 2021 and 2022, relative to an average year, from cropland fallowing and yield losses.
Jun 27, 2024
==
Drought Impacts on California Crops 3
USDA Climate Hubs (.gov)
Furthermore, farmers fallowed 37% more summer acres and 154% more year- round acres in 2015 than they did in 2011.
2 pages |
