The power of the spotlight
Political leaders like success. It can rub off on them. They are drawn to the spotlight, to the banks of cameras that circle international events. They want to be in the "family photo" that shows the people back home that they were there when history was made.
It follows that they do not want to turn up and leave empty-handed. They do not want to be associated with failure. It makes for bad headlines. As more leaders have committed to attending the climate change talks in Copenhagen, so hopes of a deal have risen too. As more heads of government promise to attend, others are drawn in. We are reaching the point where few will want to stay away.
US President Obama has changed his schedule. He was to have dropped-by this week en route to receiving the peace prize in Oslo. It would have amounted to a warm embrace and little more. He realised there was a danger that the US, the world's largest carbon emitter, would have been isolated. By attending the final two days, all the pressure will be on to sign the strongest deal.
The shape of the agreement is already clear. The world will commit itself to reducing greenhouse gases to prevent global temperatures rising two degrees which many scientists believe would be catastrophic. There will be pledges-a-plenty to cut emissions by 2050 and before but, at this stage, they are likely to be non-binding.
The second part of the deal will be to agree that these cuts are only possible if the rich countries give aid to the developing countries to help them reduce emissions even as they expand their industries.
What almost certainly will not happen is for an internationally legally binding treaty, one of the original hopes for the Copenhagen summit. Some, like British Prime Minister Gordon Brown, hope that such an agreement will follow within six months.
Even as the curtain is raised on Copenhagen one can sense the pattern of things. The pledges are coming in. President Zuma of South Africa said he would cut emissions by 42% by 2025. It was unclear what the baseline for those cuts would be, but the offer was conditional on support from the international community and "in particular, money". It comes down to: "You pay, we cut."
Then listen to President Lula de Silva from Brazil. Yes, he says, we can protect the rain forests if rich countries pay the price. The developing world sees in Copenhagen an opportunity for a transfer of funds and technology, so they want a legally-binding agreement and money on the table.
The pledges may be easier than the money. Even the EU, which has prided itself on being at the forefront of fighting climate change, has struggled to agree figures. It has stated that by 2020 100bn euros will be needed to help the developing world adapt. There is a promise that the EU "will assume its share" but there is no agreement as to what tax-payers will end up funding. There is the suggestion of somewhere between 22bn and 50bn euros. That is a wide gap. And then it has finally to be agreed who pays what and on what basis.
Some eastern European countries like Poland argue that they are struggling to reduce their emissions as it is and that they should be helped as much as the poorer countries.
Politicians find it easy to make financial pledges that extend in to the long-term future when, most likely, they'll no longer be in power. The reality is that many economies are heavily in debt and need to reduce public spending. It will be a tough sell to tell tax-payers the true costs of fighting climate change. However most environmentalists will argue that there can be no agreement without money.
Copenhagen also cannot be a success without the United States. President Obama has put a target on the table, of cutting emissions by 17% over the next 10 years. The international community will be looking for him to do more, yet he faces a sceptical Congress back home and a business community most reluctant to take on further costs as they struggle to emerge from the recession.
Chancellor Merkel of Germany compared the importance of climate change to that of the fall of the Berlin Wall. Other leaders have invested heavily in getting agreement. Copenhagen will surely deliver a world-wide commitment to fight global warming but the hard part, the money, the targets and how it all will be enforced may lie in the future.