Why was no agreement reached at Copenhagen? And why would the agreement being sought there have had no real effect on the climate situation?

The Conference was not about the climate problem but about Money.

The prevailing orthodoxy, devised by economists and financiers - not people with their feet firmly on the ground - is that the climate problem will be solved by adjustments to the Human Market in goods, services and money. There is no reason at all to believe that a few changes in taxes and charges will actually affect the real physical problem. Almost certainly if such a plan were implemented the city slickers would enrich themselves but not a single gram of carbon emission would be avoided.

After the collapse of the Copenhagen Conference they (who?) are already talking about a repeat in Mexico City. The only change from Copenhagen would be that the weather will be hot and the city one of those horrible mass urbanisations that have grown up in the last 50 years or so, themselves a serious problem. The delegates might have a small chance of seeing the misery that arises out of the various problems we face.

Practical Conference
Let us instead have a conference of the kind of people who can actually design the mitigation and reversal of the climate problem. We need Engineers with designs for the huge solar power installations we need, the Ocean Thermal Plants, the Carbon absorption schemes we need to bring the carbon back. We need anthropologists to advise on the style of life people will need to adopt if we change the energy basis of our civilisation.

The only things that count in the reversal of this problem are the very large quantity we need of energy produced to replace oil and coal, derived from the solar input, and geothermal and tide; an equally large effort is needed to reabsorb the carbon already out there, with such programmes as photosynthesis of algae for long lasting plastics to replace concrete.

When we have decided to build these things then we can talk about how to pay for them. But the money is secondary.