So we're heading down to the point of no return on some fun fun changes to the climate- specifically, a pretty dramatic increase in average global temperatures.
This has already happened, obviously, and we've got some temperature increases "loaded in" such that there's nothing we can do to stop ~1-1.5 degrees of heating, but the current expectation is that humanity is gonna hit 2-4 degrees C (with 3 degrees being the most likely) unless it starts a crash course in not emitting quite so many greenhouse gasses.
A lot of those egghead scientists put the goal at stabilizing carbon emissions at 450 parts per million (PPM). Right now we're at 387 PPM, adding about 2 PM every year. So by ~2040, we're gonna want to have ourselves stabilized and sustainable and nice sounding words like that. In order to pull this off, we have to start soon- the head honcho at the IPCC, a man selected specifically for his conservative, restrained, calm views on global warming, things things are so bad we've got 4-5 years to get things going.
Now, 450 PPM still means a good amount of warming, hell we should try to get back down to 350 PPM but not nearly as bad as your 550 PPM and 650 PPM, or, god forbid, higher concentrations than that. Let's not forget ocean acidification as well- saturated with CO2 as they are, the oceans are becoming more acidic (not becoming acid, just more acidic) which has unpleasant consequences for marine organisms...like fish. That you eat. At 850 PPM, the oceans will become anoxic. That would be bad.
So what can we do? We've got two main schools of thought on the economic side of things, and four main schools of thought on the "in general" sort of thing. Starting with the general...
: Lying conspiratorial envirocommie homosatanic liberals have made the whole thing up, we don't have to worry. Business as usual! Bring on the CO2! It's the sun, not antropogenic emissions!
: The best course of action is to avoid the worst of the warming by reducing and stabilizing carbon emissions.
: The best course of action is to accept a warmer world and take steps to prepare for it. Shift populations away from coastlines, buy up soon-to-be-fertile land in Siberia for farming, enjoy the Northwest Passage, etc.
: Develop magical super science
that can magically scrub CO2 out of the air! Build a solar shade to cool Greenland down! Start pumping out sulphate aerosols to ramp up global dimming!
My thoughts, working backwards: With the exception of a couple of simple things, geoengineering is so in its infancy we can't bet our horses on being able to fix the problem. Scientists may have already provided us with a technological solution- they gave us an early warning- and there's no guarantee a practical, workable geoengineering option will be developed in time or not have disastrous unintended consequences by itself. Adaptation is already going to be necessary or more accurately, already is necessary. Sorry Bangladesh! But it's going to be very difficult to adapt to some of the more dire "business as usual" possibilities, my personal opinion is that we should mitigate as much as we can and then brace ourselves for the need to adapt. As far as I can tell, doing nothing appears to be rather self-destructive and foolish.
The two basic economic options are:
: Straight up, full stop, tax the shit out of things that emit carbon. Want to make and sell concrete? Fuck you, we're taxing you on the shit-ton of emissions that puts out, so it makes it in your interest to figure out a way of making concrete that isn't quite as deadly to the atmosphere. This is my guess as to the best solution. The basic problem from an economic perspective is that market activity has a long-term negative externality not priced (i.e., not represented) by the system. Force the system to price carbon emissions and bingo, bango, bongo, people might stop burning down the Congo.*
*well, probably not in this case. But you get the idea.
Cap and Trade
: The less efficient but more "market friendly" (i.e., easier to cheat) system that has the added benefit of being slightly more politically palatable in the United States. The government would slap a cap on the total number of carbon emissions acceptable. Any carbon emitting company going over would have to buy permission to do so. Carbon emitting companies going under can sell that permission. This creates an economic incentive to keep ones emissions low. The Europeans tried this and it failed, because they set too weak of a cap and screwed up the implementation in several ways. I'm deeply skeptical it's a model that can work.
Every economic analysis of the costs of climate change put it as waaaaay more expensive than mitigation efforts; the Stern Review, for example, put the cost of mitigation at 1% of global GDP and the average
cost of letting it get out of hand at nearly 14% of global GDP.
So what do you folks think?
TL,DR: What should we do about global warming?