Tony Blair is using Britain’s current leadership of the G8 to focus on climate change, and one arsenal in his toolbox is a conference taking place this week on dangerous climate change. The question is, how much warming can the world take before it becomes “dangerous?”

It’s a values question, not a scientific one, though science can certainly help answer it by elucidating what will be lost or changed as current warming trends continue.

A new study by the World Wildlife Federation suggests that “dangerous levels of climate change could be reached in just over 20 years time” – climate models show the world will warm by 2 degrees Celsius sometime between 2026 and 2060, and the Arctic by up to three times that amount, by which point serious and fundamental changes will have taken place in the Arctic.

But the world is already committed to about one more degree of warming even if greenhouse gases were somehow capped at today’s levels.

Today’s New York Times has more on the political machinations behind trying to define dangerous climate change. With Kyoto so controversial (and, in the end, probably ineffective) and green technologies not being implemented fast enough, it doesn’t look promising, does it?