GREENHOUSE PHYSICS

THE BASIC
PHYSICS OF
GLOBAL WARMING
.

The most basic thing is: all molecules refect radiation. We're familiar with solids emitting heat, but even gasses do. Infra-red (IR) reflects in all directions, but at the speed of light (300,000 KmPS) it doesn't take long to find a sink ---either the ground or space. The more gas --& the bigger the molecules-- the more reflects back to the ground. Most sunlight beams right thru the atmosphere down to earth, but then is absorbed & re-transmitted as infra-red. IR, on the other hand, gets reflected around by those gasses. The more gasses, the more "greenhouse". It can be no other way. Put on a blanket, you get warmer. People in the north, especially, are aware of the blanket-effect of clouds during the night. Temps are far higher when they cover an area. But CO2 is there ALL the time!

There has always been a GH-effect. What is meant lately is... an increase in it, past what the earth (the Gaian mechanism) had evolved into a balance with... and way faster than it can keep up with. In the last 60 years, the amount has increased from 280 ppm to 365. (ppm= parts per million)

Here's the historical record. Imagine how blind you'd have to be not to see a trend here. One perfectly parallel to the rise in g-house gasses.

It would be blind to assume that this time would be different than all the other times (pre-historical) when CO2 varied --by natural means-- and the effect was catastrophic. 'Twas then... 'twill be again; but this time, it's plainly by human means.

Generally, the bigger the molecule, the better it is at reflection. CO2 isn't very big, but it makes up for it by far . in that it's very abundant. Cloroflourocarbon is very big, but doesn't occur in nature at all, so any CFC addition by man goes on top of all else. We make (& release) a horrible amount of other big ones ---especially in plastics manufacture.

As temps rise, water vapor increases, and that reflects too. A small vicious circle. But there are bigger ones. A staggering amount of CO2 is locked up in various places (clathrates, permafrost, forest litter), and much can get released by an increase in temps. Another vicious circle. This is probably why past world-heatings have been surprisingly quick.

Coal is fairly pure carbon, so it's the last thing a sane society would burn! The U.S. (& China) gets most of its electrical energy from coal. (The sulphur in it burns too, but we won't even get into Acid Rain!)

CLOUDS

This was quite a problem to get a formula for in the computers. It warms the Earth at night --like a blanket. The northern half of the U.S. knows this well. But in daytime, it's a parasol, reflecting solar input back to space. Net effect: warmer.

Aircraft contrails add a surprising amount of cloud-cover. My additional thought: even the invisible engine-exhausts, and the trails that soon disappear.. are still there as water vapor, and will contribute again (& again) to the next formation of a cloud, just as if the trails were always visible and were semi-permanent.

OTHER REFLECTANTS
The effect of melting the north polar ice cap on Earth's climate would be huge. Researchers say the ice *reflects roughly 80% of solar energy that reaches it back into space. Remove the ice, and the Arctic becomes a giant heat collector, *absorbing 80% of the sunlight that reaches the far north. It is shrinking, but so far, mostly in thickness (about half its former thickness now).
. . The results showed that the chances of the ice shrinkage since 1953 being due to natural cycles are less than 0.1%, strongly implying that humans are to blame.
. . Is there a natural cycle that heats Earth 'tween ice ages? Sure --we're in one now. Maybe it's still heating up. Maybe. If so, it'd give us a degree or two over a few centuries. What's happening now is *thousands* of times faster than that!! And the math says that it'll go even farther up the thermometer than it ever has before --especially when the ocean clatrates and the arctic permafrost (suddenly) let go of billions of tons of CO2.
. . Is the sun heating up? Yes. Add another degree every few millenia. ...Nuthin'!

A THOUGHT ON SEA-RISE. . Actually --tho we've seen no studies or discussion of this yet-- as the oceans expand and the Earth's equatorial diameter increases a few more meters (like a spinning ice-skater when she extends her arms) the Earth will slow its rotation. Oh, the amount is very, very slight, but what other effects will that have? Rotation-speed influences the Coriolus Effect, and that, in turn, the spin of ocean and air and subsurface magma currents. On it goes.... "You can't do only one thing."
. . Addendum (later news --hey, I was right! ): "Scientists say the planet has slowed recently. They'll have to add an extra second onto the end of a year more often." (There is a lunar effect too, that slows the Earth... over millenia.)

. . The atmosphere becomes more chaotic as the heat increases, because, as you recall, weather is driven by the "heat engine". More hot-air masses rise faster and it revs up like an engine, perhaps till it breaks (flops into an unpredictably different set of conditions). In 1998, there were 50% more hurricanes... need I mention 2005? 98 also set a record (even after only 11 months) for most costly weather-loss year ever --then topped by 2005. So expect a few records for cold, and for wind, as well. (An historic wind hit most of Europe in Jan '07.)

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