If talking could cut greenhouse gas emissions, then this would be a good week for international action on climate change. It opened with more than 80 speeches from governments at a special session on the issue at the UN, and will close with a two-day "summit" in the White House bringing together all the world's major emitters. The bad news is that we are still heading steadfastly in the direction of an avoidable climate catastrophe.
The special session was a bold effort by the secretary general, Ban Ki-moon, to instill urgency into climate negotiations. His aim: to prepare the ground for an international treaty with real, enforceable limits on greenhouse gas emissions. That means a more ambitious, and inclusive, successor to the Kyoto protocol, which expires in 2012. Negotiations begin in earnest in December at a summit in Bali - or they might if governments can bring themselves to stop dithering and start acting.
It's hard to exaggerate the importance of Bali. There is still a window of opportunity for avoiding the worst effects of climate change - but that window is closing. Most governments broadly accept the need to restrict average temperature increases to less than 2C above pre-industrial levels. Business-as-usual will take us over twice that level by the end of the century, so every year of delay will make it more difficult to achieve the target.
Climate change threatens to cause unprecedented reversals in human progress in our lifetime. Increased exposure to droughts, floods, storms and climatic uncertainties will reinforce the poverty trap affecting millions of the world's most vulnerable people. Future generations will have to live with potentially catastrophic ecological risks.
We need international political leadership of the highest order. Instead we are witnessing governments in the rich world conducting political manoeuvring of deckchairs-on-the-Titanic variety.
Consider the question of reducing emissions. To have a realistic chance of avoiding dangerous climate change, rich countries need to make cuts of at least 80% by 2050. Kyoto asked for cuts averaging 5%. And even this has been beyond most developed countries - the majority have increased their emissions since signing on to the protocol.
Rhetorical flourishes aside, it is hard to discern a real intent to change this picture. The US, the world's largest emitter, envisages a voluntary set of "aspirational" goals, negotiated on a country-by-country basis (no binding numbers, please).
Europeans paint the US as the sole problem, while ignoring shortcomings closer to home. The EU has some of the world's boldest targets for reductions, but energy policies are pulling in a different direction. Britain is not immune: the proposed climate change bill has adopted what is presented as an ambitious target of cutting emissions by 60%. Leave aside the fact that it excludes aviation, the fastest growing source of emissions. Forget that it falls far short of what is needed. Just look at the numbers. Emissions of carbon dioxide are higher than they were 10 years ago - and the government has virtually conceded that its target of a 20% cut by 2010 will not be achieved.
Aligning energy policies with climate change targets will require tough political decisions. While the technological fixes are available, they will be deployed only if governments change incentives. That means pricing emissions through carbon taxation, or cap-and-trade programmes that set regulatory limits. The EU's emissions trading scheme is a step in the right direction - but European governments have conspicuously failed to limit emission permits to a level consistent with its climate change goals.
What about the developing world? One of the weaknesses of Kyoto is that it does not extend to major emitting countries such as China and India. Both are high-growth economies with large populations and coal-based energy systems - a lethal concoction for global warming. As a group, developing countries now account for about half of greenhouse gas emissions, and their share is rising.
None of this should divert attention from the historic responsibility of rich nations. China may be emerging as the world's single biggest source of CO2 emissions, but adjusted for population its carbon footprint is less than one-fifth that of the US.
There are two conditions for the major emitters among developing countries to enter into a post-2012 deal. First, rich countries need to demonstrate leadership by making deep early cuts. Second, they need to put in place a "Marshall plan" for finance and technology transfer, providing developing countries with the resources they need to make a low carbon transition. The White House summit could address this question, perhaps setting the scene for a joint EU-US initiative.
Finally, before Bali, governments need to get real about the consequences of climate change. We urgently need stringent mitigation. But even the deepest cuts in emissions today will not prevent temperatures rising for at least three decades. While the rich world has the capabilities to protect citizens from the consequences, vulnerable populations in the developing world have to cope with their own meagre resources. Social justice surely demands that, having manufactured the risk, the rich world compensates the victims.
Kevin Watkins, director of the UN's Human Development Report Office.