In the aftermath of a vote that projected to the White House, uniquely in the world, a head of state who believes neither in the existence of global warming nor in the responsibility of human activity, US Secretary of State John Kerry addresses Cop 22.

Indeed in Marrakech, after a week of preparatory work by the sherpas, negotiations have entered full swing with the arrival of the first government delegations and leaders — among them Angela Merkel and François Hollande — and above all with the eagerly awaited address by the head of US foreign policy.

Who, almost as if wishing to act as a bridge between Trump's bleak electoral proclamations and actual policy, opens with:

In the time I have spent in public life, one of the things I have learned is that some issues look a little different when you are in office than when you are on the campaign trail. The majority of Americans know that climate change is real and want to honour the commitments made to the planet. The world is more united than ever — not only does it accept the challenge, but it wants to honour the commitments made in Paris.

The new attitude of the US government will therefore need to be measured over a longer timeframe and put to the test of facts. What is certain is that this, for the moment, is precisely the picture of the new and extremely delicate phase emerging from Marrakech — a conference called upon to give substance to the course set in December 2015 with the Paris Agreement. John Kerry focuses on the economy. "I am optimistic," Kerry insists, "about the markets, about the commitments the business world has made, commitments that will compel politicians to meet their targets. Investing in clean energy is an economically sound choice. No nation will be better off if it stays on the sidelines."

The final bill of a high-CO2 economy includes far more than just the price of oil or coal, or natural gas, or the cost of building thermal power stations. A proper accounting of real costs requires fully considering all the downstream consequences, which, in the case of dirty fuels, are sufficient to at least double or triple the initial expenditure.
This is the kind of calculation we need to make today. Just consider the price of environmental and agricultural degradation. Think about the loss of capacity of farmers in a region due to a lack of water or too much heat to grow their crops today. Think about the hospital bills for asthma and emphysema, and the millions of deaths linked to air pollution caused by the use of fossil fuels.

Thus, in his final speech as US Secretary of State, John Kerry sought to emphasise the idea that tackling global warming could give the economy a boost, unlocking substantial investment in green technologies and renewable energy. At the same time, he warned that any country that does not take part in the fight not only jeopardises everyone's goals, but also excludes itself from the wave of jobs and economic benefits brought by the ecological revolution.

No nation will do well if it sits on the sidelines, depriving its businesses of the opportunity to benefit from the advantages of the clean technology boom. Millions of people around the world are currently employed in renewable energy, and if we make the right choices, millions more people will be at work. The market is clearly heading towards clean energy, and the trend can only become even more pronounced.