They made some progress at the annual December round of the international negotiations on controlling climate change, held this year in Qatar. They agreed that the countries that cause the warming should compensate the ones that suffer the most from it. The principle, known as the Loss and Damage mechanism, has no numbers attached to it, but it's a step forward. The only step forward, unfortunately.
In the first phase of these talks, which concluded with the Kyoto Protocol of 1997, the emphasis was on "mitigation"; that is, on stopping the warming by cutting human emissions of carbon dioxide and other "greenhouse gases". Fifteen years later, emissions are rising, not falling.
So gradually the emphasis shifted to "adaptation". If we can't agree on measures to stop the global temperature from going up, can we learn to live with it? What's the plan for developing new crops to withstand the droughts and high temperatures that are coming? What's the plan for coping with massive floods that drown river valleys and inundate coastlines?
Well, there are no such plans in most places, so the emphasis has shifted again, to compensation. Terrible things will happen to poor countries, so who pays for them? In principle, says the new Loss and Damage mechanism, the rich countries that are responsible for the warming pay. It will become a lawyers' playground of little use to anybody else.
So if mitigation is a lost cause, and if adaptation will never keep up with the speed at which the climate is going bad, and if compensation is a nice idea whose time will never come, what is the next stage in these climate talks?
There will be a fourth stage to the negotiations, but first we will have to wait until rising temperatures, falling food production and catastrophic storms shake governments out of their present lethargy. That probably won't happen until quite late in the decade - and by then, at the rate of emissions, we will be well past the point at which we could hold the rise in global temperature down to 2 degrees C. We will, in fact, be on course for 3, 4 or even 5 degrees C of warming, because beyond plus 2 degrees, the warming that we have already created will trigger "feedbacks": natural sources of carbon dioxide emissions like melting permafrost which we cannot shut off.
So then, when it's too late, everybody will really want a deal, but just cutting gas emissions won't be enough. We will need some way to hold the temperature down while we deal with our problem, or else the temperature goes so high that mass starvation sets in. The rule of thumb is we lose 10 per cent of food production for every rise of one degree C.
There is a way to stop the warming from passing plus 2 degrees C and triggering the feedbacks, during the decades it will take to get our emissions back down. It's called "geo-engineering": human intervention in the climate system. Our greenhouse gas emissions are an inadvertent example of geo-engineering that is pushing the climate in the wrong direction. Another, deliberate kind of geo-engineering may be needed to stop it.
Geo-engineering to hold the heat down is possible, though the undesirable side-effects could be very large. The biggest problem is that it's cheap: Dozens of governments could afford to do it - and just one government, acting alone, could do it to the whole atmosphere.
So the fourth phase of the climate talks, will be about when it is time to start geo-engineering, and what techniques should be used, and who controls the process. They won't agree on that either, so things will drag on further until some government, desperate to save its people from starvation, decides to do it alone. That could cause a major war.
So we had better hope neutral observers like the fossil fuel industries are right in insisting global warming is a fraud. Maybe all those scientists really are making it up just to get more money in research grants. That would be a happy ending.
Gwynne Dyer is an independent journalist whose articles are published in 45 countries.