Christiana Figueres, Founding Partner, Global Optimism, on Centre Stage during day two of Web Summit 2019 at the Altice Arena in Lisbon, Portugal.

DAVOS, Switzerland — The architect of the landmark 2015 Paris Agreement told CNBC on Monday that it cannot be easy for President Donald Trump to justify his approach to the climate crisis — both to himself and citizens of the world.

Speaking on the sidelines of the World Economic Forum (WEF) in the Swiss Alpine town of Davos, Christiana Figures, former United Nations Framework Convention on Climate Change (UNFCC) said Monday: "I always wonder: How can he face himself?"

"How can he face his children and his grandchildren? How can he face citizens of the United States and of the world? I don't understand how he can do that."

Figueres' comments come as policymakers and business leaders arrive in Switzerland for the WEF's four-day annual conference, with those in attendance scheduled to focus on the intensifying climate crisis.

The event, which is often criticized for being out of touch with the real world, has said it aims to assist governments and international institutions in tracking progress toward the Paris Agreement and the UN's Sustainable Development Goals.

It follows the hottest year on record for the world's oceans, the second-hottest year for global average temperatures and wildfires from the U.S. to the Amazon to Australia.