Campaigners have had trouble with this, as the 450 ppm target was regarded by many as impossible to achieve anyway. This is no reason for anyone to deny the science, and Hansen is the best climatologist there is. At least, so says the President of the National Academy of Sciences, Ralph Cicerone. I heard many reports from Poznan where a delegate would describe how terrible it was that the governments weren’t accepting “the best science” or however else they wanted to describe it, yet these delegates weren’t accepting the best science themselves as they called on the governments to work toward achieving 450 ppm. 450 ppm by 2050 is to say lets work together for 42 years and then we can hand our descendants a planet committed to global catastrophe.

Its been a mistake, and Gore is showing real leadership as he seeks to persuade people to rectify it.

Twenty years ago, I attended the 1988 Changing Atmosphere conference in Toronto. This was before the creation of the IPCC, and before climate change was a front page issue. That conference is held to be a bit of a landmark, as it helped to put this issue on the main table for discussion.

Anyway, there, the delegates had no problem describing global warming as threatening consequences that could only be exceeded by “global nuclear war”, yet they called for no stabilization target, merely reductions that added up to “slowing this down”, which was the underlying line conference organizers wished to get out.

I was horrified. Civilization was being told all it could do was to slow down the rate at which it accelerated into planetary catastrophe that could only be compared to global nuclear war. I was the only delegate who stood, when they were about to put words into their final statement saying the changes could not be reversed, to say no, this can be reversed. No one stood against me, but no one supported me either. Still, they didn’t put those words into their final statement, and Canada’s Ambassador to the UN, the conference chair, interrupted the final plenary to ask me to stand and be recognized for my contribution. Obviously, I was saying what many of the rest of the delegates felt they couldn’t say, or what they wished there were a few billion more people like me out there saying.

If you are sailing into a planetary catastrophe, the only thing to do is advocate that the ship be turned around. This is the significance of Gore’s speech in Poznan calling for a new target. 350 ppm means the changes that have happened to the atmosphere must be reversed. Hansen has been saying the science supports this for about a year. I thought the science supported it twenty years ago. Its far past time for people to drop their denial and accept the best science.

People think they have to have a plan to achieve a goal before they accept the goal. This is a mistake. We’ll never get to where we have to go if we never accept that 350 ppm or even less is where we have to go. Stabilizing the composition and taking some greenhouse gas out of the atmosphere is the only “safe” thing to do. Its incredible that negotiations have been going on for so long and only now is a realistic target mentioned in a speech, with the target yet to be considered as necessary by any of the parties to the agreement, but there it is.

In your statement I see no reference to a target level of greenhouse gas, and I believe you should consider rectifying this. The most vital matter is to reduce greenhouse gas emissions as quickly as possible to as low of a level as possible as humanity’s net contribution must at some point become negative, i.e gases have to come out of the atmosphere.