"the heat radiates out to space."
It would, but for the GHGs. That's the crux of the problem. Tyndall figured that out 150 years ago. You must have been sick the day he presented that paper.
The Greenhouse Effect
The "greenhouse effect" is the heating of the Earth due to the presence of greenhouse gases. It is named this way because of a similar effect produced by the glass panes of a greenhouse. Shorter-wavelength solar radiation from the sun passes through Earth's atmosphere, then is absorbed by the surface of the Earth, causing it to warm. Part of the absorbed energy is then reradiated back to the atmosphere as long wave infared radiation. Little of this long wave radiation escapes back into space; the radiation cannot pass through the greenhouse gases in the atmosphere. The greenhouse gases selectively transmit the infared waves, trapping some and allowing some to pass through into space. The greenhouse gases absorb these waves and reemits the waves downward, causing the lower atmosphere to warm.(www.eb.com:180)
umich.edu
"Imagine how improved things would be if the Arctic was a year-round seaway and Greenland was green and pleasantly habitable."
Sounds like paradise...for a gila monster. I'm sure you have a method to keep the rest of the world habitable while this happens...talk about living in LaLa Land.
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.
timesonline.co.uk |
