The president used his speech at the forum to attack climate "prophets of doom" and snubbed their "predictions of the apocalypse" in favour of "optimism" for the future.
In the past, the president has characterized the world's largest single market as a "foe" that has taken advantage of the American economy.
The US President and Greta have been involved in a tit for tat since a year ago.
Although the world, through the Paris climate deal, has committed to keeping temperatures well below 2.0C (3.6F) above pre-industrial times and endeavoured to keep the rise to 1.5C, scientists say we are well off that target.
But European Commission chief Ursula von der Leyen emerged from a "very good conversation with" the president in Davos talking up the prospects of a deal covering trade, technology and energy.
Mnuchin also said that the USA was ready to strike a new trade agreement with the United Kingdom after it leaves the European Union.
"I would be very surprised if I had to implement the tariffs", he said. "I didn't want to go with China and Europe at the same time", he said.
The US and European Union agreed to pursue a trade deal in July 2017 as a tentative truce after Trump had taken office and declared a war on America's yawning trade deficits with the likes of China and Europe.
"The world is on fire", she said.
Trump is scheduled to spend the rest of his two-day visit to Davos in meetings with business executives and other world leaders. "It's a proportionate tax and it's deliberately designed as a temporary tax, so it will fall away once there is an global solution".
Mnuchin emphasised the USA was still involved in the OECD dialogue, but insisted that a digital tax was "discriminatory in nature". I did not... I think that some people are... they put it in a level that is unrealistic to a point you can't live your lives.
France, which considered a similar tax, agreed this week to suspend down payments for this year's digital tax after Washington threatened retaliation with tariffs on French wine. "What happens if he reveals what I think about a certain leader and it's not very positive?" he said, adding that Pompeo testifying would also be a risk.
Trump said Wednesday that he "can live either way" with the Senate's decision about whether to call witnesses at his impeachment trial, but argued that testimony by former national security adviser John Bolton could pose several concerns.
"We're very much looking forward to a new trade agreement with the U.K. That's a big priority of ours for this year".
Hugo Weaving Not Returning as Agent Smith in Matrix 4
Unfortunately, we can't say for sure, as we really don't know a whole heck of a lot about The Matrix 4 right now. I was in touch with Lana Wachowski , but in the end she decided that the dates weren't going to work.
Smoking Marijuana Can Be Hard on Your Heart
"Some observational studies have suggested an association between marijuana and a range of cardiovascular risks", lead author Dr. Surveys have found that marijuana smokers were three times more likely to experience a cerebrovascular event, such as a stroke .
Ovechkin nets 690th career goal, tying Lemieux for 10th all
Brady Tkachuk had a goal and assist and was on the winning side for the first time in four games against older brother Matthew. Alex Ovechkin finished with a hat trick as the Washington Capitals defeated the visiting New Jersey Devils, 5-2, on Thursday.
Spain walloped by heavy snow, rain, gales that leave 2 dead
The storm generated massive waves and gale-force winds that smashed into seafront towns, damaging many shops and restaurants. Local officials report that a man died in his home in the Spanish province of Ávila after being hit by flying roof tiles.
Serena rides second wind to third round
Tamara Zidanšek has had a good start to the tournament but I don't see her having the intensity required to compete with Serena. Williams needed just 19 minutes to win the first set but 18-year-old Russian dug in to at least make the scoreline respectable.