So too were a number of other conditions that Europeans and others would have liked, such as a date for peak emissions.

ECONOMIST: Climate change after Copenhagen

So from their point of view, asking rich nations to peak their emissions within a few years and halve them within five isn't unreasonable - especially, as another portion of the text says, that the problem of greenhouse warming has been on the radar for so long that rich countries could have peaked their emissions during the 1990s if they had wanted to.

BBC: Durban: Climate summit looks back and forward

Mr Harvie called for a legally binding global treaty which made 2015 a global peak year for emissions and he said there was a need for support for low carbon development in poorer countries.

BBC: 'UN Climate Summit' debate 2

CO2 emissions must eventually peak and gradually decline toward zero, regardless of whether we go for a target of 350ppm or 1, 000ppm.

ECONOMIST: Blowing hot and cold

You want a guarantee of safety - not something along the lines of "if we peak at date X and reduce emissions at rate Y that gives you Z% chance of not being flooded out of existence".

BBC: Durban: Climate summit looks back and forward

Developed nations whose emissions have not yet peaked must make them peak and begin to decline immediately.

BBC: Durban: Climate summit looks back and forward

Cooling might take the edge off the peak of a planetary fever, or perhaps buy time as emissions cuts begin to have the desired effects.

ECONOMIST: Geoengineering

The rate of greenhouse gas emissions is rising and we're rapidly approaching the date by which science suggests they need to peak if there's to be a reasonable chance of keeping the temperature rise under 2C.

BBC: Durban: Climate summit looks back and forward