Stressing on adoption of clean technologies by nations, Kerry, speaking at the UN climate talks here, said nearly 20 million new asthma cases a year in India linked to coal-related air pollution. "Now, significantly, the renewable energy boom isn't limited to industrialised countries, and that's important to note. In fact, emerging economies like China, India, and Brazil invested even more in renewable technologies last year than the developed world," he said.

"China alone invested more than 100 billion dollars. Ultimately, clean energy is expected to be a multitrillion dollar market – the largest market the world has ever known. And no nation will do well if it sits on the sidelines, handicapping its new businesses from reaping the benefits of the clean-tech explosion," he said in his speech.

Noting that world is already changing at an increasingly alarming rate with increasingly alarming consequences, he said the impacts of global warming are now evident across the world with record-breaking droughts, rising sea levels, unusual storms and millions of people displaced by weather events. "We have seen record-breaking droughts everywhere – from India to Brazil to the west coast of the US. Storms that used to happen once every 500 years are becoming relatively normal.

In recent years, an average of 22.5 million people have been displaced by extreme weather events annually. We never saw that in the 20th Century," he said. He made a stirring appeal to all countries including his own to press ahead with the fight against climate change, saying a failure to do so would be a "betrayal of devastating consequences."

Without mentioning US President-elect Donald Trump by name in his speech, he said "At some point even the strongest skeptic has to acknowledge that something disturbing is happening." Republican president-elect has called global warming a "hoax" and has pledged to "cancel" the Paris deal limiting greenhouse gas emissions.

Noting that there are challenges that countries face because they have a big population, growing economy, and a lot of people in poverty, Kerry said that those countries too are determined to maintain stability and pull those people into the economy.

"And of course, they’re concerned about stability. We all are. Access to affordable energy is a key part of providing that stability. And the dirtiest sources of energy are, unfortunately, some of the cheapest. But I emphasise this only in the short term. In the long term, it’s an entirely different story.

"In the long term, carbon-intensive energy is actually today, right now, one of the costliest and most foolhardy investments any nation can possibly make. And that is because the final invoice for carbon-based energy includes a lot more than just the price of the oil or the coal, or the natural gas, it or the price of building the power plant," he said.

"The real cost accounting needs to fully consider all of the downstream consequences, which, in the case of dirty fuels, are enough to at least double or triple the initial expenses," Kerry said.