Global Dimming? What the hell is this, do we really need another Global ____ing crisis of some kind?
It's exactly what it sounds like, enough stuff gets into the atmosphere that it blocks the sunlight enough to shift temperatures. It's happened in the past due to the previously mentioned supervolcanoes, and it could be happening now in some parts of the world, due to pollution.
Angelinos will be unable to notice this phenomenon.
Whoa, wait a second. If it's making the world cooler, and the big problem is warming, then what the hell are we complaining about? It's less a natural disaster and more of an ironic superhero.
...Until you get to the side effects. Global dimming happens now because some pollutants act as cloud "seeds," that is water molecules in the air cling to them and form clouds. These pollutants form more and smaller collections of water, making the clouds denser and shinier, and therefore reflecting more light back into space.
These same pollutants are the ones responsible for acid rain, smog and a handful of other nasty shit. It also causes changes in weather patterns, leading to greater rainfall in some areas and droughts in others.
Some people believe that global dimming might have already lead to the massive droughts that ruined Africa back in the 70s and 80s, but the real shitstorm comes from the belief that if we cut back on the emissions that cause global dimming, global warming will suddenly accelerate and fuck us all, because that may be one of the mechanisms keeping global warming in check.
So Are We Doomed?
At the end of the day, most of the practices that cause the dimming also cause the warming. Going green fixes both problems in the long run. So while some people have actually suggested increasing the dimming to prevent the warming in the short term, this is kind of like killing a hooker and instead of just calling a lawyer to plea down to manslaughter, killing all of the witnesses in hopes that somehow you'll eventually kill enough people that the cops will stop investigating. It really doesn't work that way.
Or, on more scientific terms, Gavin Schmidt from NASA says:
"Ideas that we should increase aerosol emissions to counteract global warming have been described as a 'Faustian bargain' because that would imply an ever increasing amount of emissions in order to match the accumulated greenhouse gas in the atmosphere, with ever increasing monetary and health costs."
Of course, "monetary and health costs" would be the Vengeful Pimp in this analogy.
You can immediately see from the title of this entry that this phenomenon has two names, and that one of them has to be utterly inappropriate. Either the situation is wacky and harmless like a burp, or it's something you'd name after a fucking sci-fi supervillain's doomsday weapon (a "Clathrate Gun").
So which is it?
Methane burps are, sure enough, huge belches of methane coming from the ocean floor and permafrost, and they make an 18-wheeler's carbon footprint look like a baby koala. Since they're a terrifying death sentence for life as we know it, we should probably be calling it the Gun thing from now on (so-named because once this is set in motion, it is unstoppable, just like firing a gun).
It works like this: Heating in the atmosphere causes the permafrost to thaw, or for underwater methane clathrate deposits to release. Methane is much more powerful than carbon dioxide as a greenhouse gas, so it would drastically cut the amount of time global warming needs to take hold.
The shitty news? The sudden increase in temperature would spur the release of even more methane, which would raise the temperature even more, which would release even more methane... You get the idea (and the bullet analogy).
So Are We Doomed?
The bad thing is, this isn't something concocted by eggheads crunching numbers on theoretical doomsday scenarios. It has happened before. Twice.
The second time was about 55-million years ago and screwed up the environment for almost 100,000 years. The first was in the wake of the aforementioned supervolcano from 251-million years ago that, as we said, killed off almost every living thing on Earth.
See, volcanoes can also cause global warming (due to CO2 they release) so with CO2 again on the rise--this time thanks to thousands of power plants and millions of cars--it's at least possible the trigger could get pulled on the Clathrate Gun. But how likely is it?
Right now, we have no freaking idea. So why not call it the "Methane Russian Roulette Hypothesis?" Because scientists have no imagination, that's why.
Do you have something funny to say about a random topic? You could be on the front page of Cracked.com tomorrow. Go here and find out how to create a Topic Page.
To see how else our frail meatsacks can be destroyed, check out 5 Cosmic Events That Could Kill You Before Lunch and 5 Bizarre Ways the Weather Can Kill You Without Warning.
And stop by our Top Picks (Updated 02.02.2010) to see how the Internet can destroy the planet.