But we are almost certainly going to miss our [global warming] deadline. We cannot get the 10 lost years back, and by the time a new global agreement to replace the Kyoto accord is negotiated and put into effect, there will probably not be enough time left to stop the warming short of the point where we must not go.

The real requirement, if we are to avoid runaway global warming, is probably 80% by 2030, and almost no burning whatever of fossil fuels (coal, gas and oil) by 2050.

It doesn't matter what we think we are there [in Afghanistan] for; it matters what they think. They think we are invaders.

While the high-level climate talks pursue their stately progress towards some ill-defined destination, down in the trenches there is an undercurrent of suppressed panic in the conversations. The tipping points seem to be racing towards us a lot faster than people thought.

There is a point of no return after which warming becomes unstoppable - and we are probably going to sail right through it. It is the point at which anthropogenic (human-caused) warming triggers huge releases of carbon dioxide from warming oceans, or similar releases of both carbon dioxide and methane from melting permafrost, or both. Most climate scientists think that point lies not far beyond 2 degrees C hotter (3.6 degrees F).

For most of history, war has been a more or less functional institution, providing benefits for those societies that were good at it, although the cost in money, in lives, and in suffering was always significant. Only in the past century have large numbers of people begun to question the basic assumption of civilized societies that war is inevitable and often useful.

Fiat justitia, ruat coelum. (Do the right thing even if the heavens fall.) It's not nearly as naïve a maxim as it seems, because in the real world it often turns out that doing what is morally the right thing is also, in practical terms, the right thing to do.