Donald Trump has attacked climate activists in front of Greta Thunberg as he revealed the US is signing up to a project to plant one trillion trees

In a speech in Davos, Switzerland, the US president called those calling for more action on climate change "perennial prophets of doom" and the "heirs of yesterday's foolish fortune tellers".

Teenage activist Thunberg was among those watching Mr Trump at the event, having earlier warned that planting trees is "nowhere near enough".

Image: Greta Thunberg was in the audience to watch the US president

It comes after Mr Trump unilaterally pledged to withdraw the US from the Paris Climate Accord, which aimed to cut CO2 emissions to a rate that will limit global warming to 1.5C.

He made his comments at the World Economic Forum in Davos after its founder Klaus Schwab made climate change a key topic.


To applause, Mr Trump told the forum: "Today I'm pleased to announce the United States will join the one trillion trees initiative being launched here.

Thunberg calls out 'empty words' at Davos

"And in doing so we will continue to show strong leadership in restoring, growing and better managing our trees and our forests.

"This is not a time for pessimism. This is a time for optimism. Fear and doubt is not a good thought process because this is a time for tremendous hope and joy, optimism and action.

"But to embrace the possibilities of tomorrow we must reject the perennial prophets of doom and their predictions of the apocalypse. They are the heirs of yesterday's foolish fortune tellers."

His words came in stark contrast to those of 17-year-old Thunberg, who spoke earlier on the first full day of the forum about the "crisis" she said was occurring.

The Swedish teenager told delegates: "Planting trees is good of course but it's nowhere near enough. It cannot replace mitigation."

She accused leaders of "cheating and fiddling around with numbers" by talking about cutting emissions to net-zero and added that her calls for more action were based on science, not on irrational fears.

"My generation will not give up without a fight," she said.

Mr Schwab had earlier outlined his plans to launch a scheme to plant a trillion trees using public and private funds by the end of this decade.

The idea was not new and a number of organisations and activists have already been promoting the idea for some years.

Image: Thunberg spoke at a session during the World Economic Forum

Experts say the number of trees on the planet has declined from its previous high of six trillion to its current three trillion, so replanting one trillion would go some way to offsetting the carbon emitted into the atmosphere by industrialised nations.

Mr Trump's pledge to join the project, however, was a deviation from the main theme of his speech in which he claimed US economic success since he came to office - something he said had been achieved as a result of deregulation.

While claiming to be a "big believer in the environment" and wanting "the cleanest water and the cleanest air", he spoke with pride about the expansion of US oil and gas production.

Most ecologists believe more controls on industry and a sharp reduction in oil and gas use are required if carbon emissions are to be cut to a level that will limit climate change.

Nobel prize winning economist Joseph Stiglitz told Reuters afterwards he found Mr Trump's comments "astounding", adding it was "As if what we are seeing with our eyes are not there".