The difference between greenhouse gas (GHG) stabilization levels and GHG peak targets is one we've failed to adequately explain. I may make a botch of this, but here goes:

Stabilization levels are our long-term goals: when Jim Hansen says we need a concentration of carbon dioxide in the atmosphere no more than 350 ppm, he's discussing where we need to end up in a certain time frame (many use the time frame 2050 or 2100 -- I'm not sure what Hansen's time frame here is). Though we're already over that level, with concerted effort and widespread innovation, we could bring CO2 concentrations down.

Peak target is another kind of measurement, a threshold above which we should stray. The consensus opinion here seems to be hovering around 450 ppm: meaning that if we exceed that amount of CO2 (and other GHGs) in the atmosphere, we're running serious risk of quickly crossing catastrophic tipping points.

I imagine an engine. For optimal performance and longevity, we should only run it so fast. It can be run faster, but wear and tear (and the possibility of break down) increase rapidly the longer we run it at faster speeds. Some speeds, however, are just too fast: above those speeds, we're likely to just burn the engine out altogether.

Stabilization level is the fastest speed at which we believe we can safely run the engine over time: peak target is the red zone, the speed at which the engine should never go.

(Thanks to Tariq Banuri for pointing out this key concept.)

There are 6.5 billion people on the planet. The earth can absord about 5 billion tons of CO2 per year. That means everyone can make no more than about 0.8 tons/year.

Americans make 20, Europeans about 10, Cubans about three, and sub-Saharan Africans less than one.

I'd sure like to know how any leaders or people could stop CO2 levels from increasing for the forseeable (like 2050 or later) future, much less bring them down.

DK

Posted by: dooberheim on January 7, 2008 4:38 PM

I've just watched a BBC Horizon show about "Global Dimming" and it sounds like the increase in temperature is going to devastate the now green spaces in the world within a few decades time. I would like to talk about the introduction of a Gandhian economic principle called "trusteeship". This idea stems from basic needs vs. basic wants in humans, but especially First-World citizens trying to get a leg up on the family next door. This is a method of non-ownership where a person must justify their use of a possession to a community, before buying or using that thing.

So I buy a new hybrid car. Great ! This uses half the gas that a normal vehicle uses because it idles on a battery, and reduces all around carbon output. Now I am still going to drive that hybrid car to work every day alone, and my ride is six km from home. Before I get the keys to my new forest green hybrid vehicle I have to speak with some members of my family, neighborhood, workplace, or some form of community member. If I can't find a friend to carpool this ride with, or take public transit to work, they will deem it fit for me to take this car into work every day by myself. If they can find another way for me to get to work daily, I have not justified my "trust" in the vehicle, and therefore don't have permission to use this possession every day. The onus is on the user or buyer of the thing who must constantly be creating something positive out of that possession, thus justifying the "trust" in that thing before a group of their own peers

This was a little long winded, but the idea remains that personal possessions should not be ours to protect and hide in, but ours to justify. Our own responsibility to defend to our peers.

Posted by: Pastis on January 16, 2008 2:02 AM