Invited by then British Prime Minister Tony Blair to the 2005 Group of Eight summit in Gleneagles as diplomatic window dressing to show the global scope of climate change, Mexico, India, China, South Africa and Brazil were kept on the sidelines and told what they had agreed to after the event.

Two years later at Heiligendamm in Germany they got the same treatment, being invited into the main meeting and handed the final G8 plus five statement.

This year in Hokkaido, Japan, they finally bit back, calling themselves the G5, issuing their own statement and challenging their rich northern neighbours to do far more on tackling the global warming crisis.

Not only that, but the G5 has also agreed to hold its own regular meetings, carving out its own climate agenda and challenging the United States, Britain, France, Germany, Canada, Russia, Japan and Italy to do far more than agree the world should cut carbon emissions by 50 percent -- from an undecided base year -- by 2050.

"In the climate change perspective it is the last time that the G5 could be regarded as the G8's former colonies whose interests are subjected or subservient to that of the rich countries. The G5 and the developing countries more and more will decide for themselves," South African environment minister Marthinus van Schalkwyk said on Friday on a brief stop-over in London on his way back from the summit.

"The G5 put forward a view on long-term commitments and targets and mid-term targets and a base year, 100 percent united on its proposal. On the other side you had the G8 bringing forward a very vague proposal that basically represents the lowest common denominator in their ranks -- basically the U.S.

"With regard to climate change I have no doubt that this last week equalled the playing field between developed and developing countries," he said.

Van Schalkwyk, an ardent environmental advocate and champion of the developing nations, said the rich world which had created the climate crisis had to cut carbon emissions by 25-40 percent by 2020 and 80-95 percent by 2050 -- a target that is in another universe from current G8 aspirations.

For their part the developing world would agree to commit to a relative cut in emissions by deviating below business-as-usual projections. That is far short of what the United States in particular has been calling for.

The next 18 months leading up to the United Nations meeting in Copenhagen which is supposed to decide a successor to the Kyoto Protocol should be a fascinating and probably bruising time in global climate diplomacy. The tail is starting to wag the dog.

Already some voices are being raised to call for a slowdown in actions to curb carbon emissions because of the cost involved, facing politicians with the apparent choice of bowing to the calls from their constituents in the hope of keeping their seats at the next election or standing firm because it is the right thing to do for the long term.

British Energy Minister Malcolm Wicks acknowledged the dilemma at a seminar in the House of Commons on Wednesday, noting that affordability was a tricky issue and urging his fellow politicians to guard against the pressures to take their feet off the climate accelerator.

The issue was thrown into stark relief by a report from the Centre for Policy Studies think tank that said meeting the European Union's renewable energy target of 20 percent by 2020 could cost more than 4,000 pounds per household.

This is in part because the space in Britain for onshore wind farms is running out, offshore costs more than twice as much and tidal is in its infancy.

But in part at least it is a false choice. Numerous studies show categorically that many actions like improved home insulation, turning down air-conditioning or central heating thermostats, using less water, recycling and changing lightbulbs save more than they cost very quickly and involve little effort.

At the same time there are vast, and as yet largely untapped, savings to be had from improved energy efficiency. The trick is to inform and persuade the public.

As another speaker at the meeting said by way of illustration -- it is like two economists walking down the street when one spots a $100 bill on the pavement. "Look," he says to his companion. "A $100 bill on the pavement". To which his colleague replies; "There can't be otherwise someone would have picked it up already."

The failure to act effectively on energy efficiency is a bit like having pavements strewn with $100 bills, the speaker noted.

To many people that may seem a total contradiction in terms given that aviation emissions are far worse for the atmosphere than those at ground level and that video conferencing is now readily available.

Add to that the fact that the Bali meeting of United Nations environment ministers and their support staff will in fact do almost nothing concrete to tackle the climate crisis, with even the most optimistic observers suggesting that the best outcome will be to set the agenda for more talks, and the contradiction becomes almost tangible.

But while proponents accept that it would appear somewhat absurd to emit the carbon equivalent of a small country simply to agree to talk about talks on cutting those very same emissions, they argue that nothing yet invented beats face to face, body language to body language meetings late into the night in stuffy rooms to broker a deal.

As one observer remarked recently: "You don't do backroom deals in video conferences".

That may well be true. But it does seem to be a sad reflection on humanity that it's future still relies on such brinksmanship.

Is that really the right signal to be sending to a public who are already sceptical about the massive gulf between the political rhetoric urging action by all and the actual reality of tackling what is described as the worst crisis to face humanity?