[Tchocky]

Originally Posted by August

So the general idea, if i understand it correctly, is that Trenberth believes we have no reliable means for measuring climate change, or the human impact upon it, but since we do produce greenhouse gasses man must have some effect upon that change.

Um, no. The article (source, not Carter's....thing) discusses the weaknesses in climate prediction modelling, nothing about measuring what is already happening. The thrust of the paper is healthy and grounded, we don't know everything, and it's dangerous to assume we do. The final paragraphs make clear the necessity for a comprehensive climate model. A model that we don't currently have. The flaws in current climate modeling are well illustrated in the article
However, when the best information to hand suggests a serious situation, as it does with climate change, you have to act. Not-complete information is often confused for contrary information.

And this is what we're expected to make national policy with?

Well, global policy. And yes.

So the science is just beginning. Beginning, that is, to face up to the challenge of building a climate information system that tracks the current climate and the agents of change, that initializes models and makes predictions, and that provides useful climate information on many time scales regionally and tailored to many sectoral needs.

No matter how much they try to limit our "carbon footprint", unless they first find some way to stop the never ending increase in the global human population their efforts are doomed to failure. Every new person born will just add more to our overall output.

That depends on the future energy consumption model of each future child. Which depends on the energy models of their parents, us.
We've already started to combat this future problem, sixteen thousand children die every day of hunger.
Actually, I've no idea how population growth will affect/be affected by global warming.