Paris 2015

Climate change should keep us 'up at night': World Bank

Climate change is something that should keep us all "up at night," World Bank President Jim Yong Kim told CNBC, dismissing the skepticism among prominent politicians – especially in the U.S. – that man-made climate change is even occurring.

"As an American and as someone trained in science, the denial of the reality of climate change is really disappointing," World Bank President Jim Yong Kim told CNBC Monday.

"The science is absolutely clear, and 98 percent of climate scientists agree that man-made climate change is real and that the effects of climate change and a warming planet are much more severe at 0.8 degrees than we would have imagined," Kim said, referring to how much higher global temperatures are today than they were in pre-industrial times. Kim was speaking on the sidelines of the COP21 climate change summit in Paris.

Over 130 world leaders were gathering in Paris Monday for the United Nations conference on climate change and there are hopes that progress can be making the reduction of greenhouse gas emissions a priority for national governments, particularly the U.S. and China, who are the largest emitters.

Described by its organizers as a "crucial" event, COP21 will see world leaders attempt to come to, "a new international agreement on the climate, applicable to all countries, with the aim of keeping global warming below 2 degrees Celsius."

Polar bear on a wide surface of ice in the russian arctic close to Franz Josef Land.
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Despite a general global consensus that climate change is potentially catastrophic for mankind, there are still naysayers, particularly among Republican political circles in the U.S. For one, billionaire Donald Trump, a Republican presidential candidate, has said that he doesn't believe climate change exists.

"Unless somebody can prove something to me, I believe there's weather. I believe there's change," he told a radio talk show in September.

A cement factory releasing heavy smoke in Binzhou, China.
AFP | Getty Images

The tide appears to be turning, however, with climate change deniers becoming increasingly a minority. Kim said the science supporting evidence of climate change was overwhelming and that politicians had a responsibility to mind climate change phenomena.

"This is about science, this is ethics and this is about your children and grandchildren, " Kim said. " I know that these politicians care about their children and grandchildren …and I think that as more extreme weather events hit the United States, people will begin to realize that what they're leaving for their children is something that should keep them up at night."

Worst El Nino 'in 50 years'

Extreme weather events believed to have been caused by man-made climate change are becoming more frequent and harder to ignore. Devastating floods, droughts and tropical cyclones have all been attributed to climate change and have hit all parts of the world. Most recently, the extreme weather system known as "El Nino" has come high on the agenda for scientists and environmentalists analysing climate change.

The "El Nino Southern Oscillation," to give it its full name, is the warming and cooling of the Pacific Ocean away from its average temperatures, often resulting in severe weather such as floods and droughts. La Nina is the cooling phase, and El Nino is the warming phase.

The World Bank president warned that the current El Nino pattern is expected to be one of the strongest in decades.

"I don't know what it is that we can do to make it any more vivid but I tell you, El Nino is about to hit and the waters off Lima, Peru are six degrees Celsius above normal and in previous episodes it's been about 2 degrees Celsius above normal so this is going to be the worst El Nino in 50 years."

Security measures are seen during final preparations for the COP21, Paris Climate Conference site on November 26, 2015 in Le Bourget, France.
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The World Bank states on its website that all development in the world is now taking place "in a world shaped by climate change." The bank states that it "is concerned that without bold action now, the warming planet threatens to put prosperity out of reach of millions and roll back decades of development."

There are hopes that at this year's summit in Paris, world leaders can come to a legally binding agreement on reducing greenhouse gas emissions and in the process, help to protect the world's poorest from suffering the devastating effects of climate change such as floods destroying homes and livelihoods. Kim said the time for action was now.

"We have done our calculations and if we don't have a active and vigorous response to climate change, by 2030 an additional 100 million people will be plunged into poverty. So for us, tackling climate change is not just about preserving the planet – which is critically important -- but it's also about making sure the poorest don't suffer the most. When there are extreme weather events, the poorest suffer the most."

- By CNBC's Holly Ellyatt, follow her on Twitter @HollyEllyatt. Follow us on Twitter: @CNBCWorld

Correction: An earlier version of this story misstated how much warmer the planet is today than it was in pre-industrial times.