Many citizens noted that Thunberg, which chastised Western countries for not doing enough to address climate issues, never criticized China or India, which are among the world's worst polluters.
"Well she's remarkable. She represents one of the main reasons why I've been trying to make all this effort all these years", he said. "Obviously, those demands have been completely ignored".
At a press conference in the Swiss ski resort, Ms Thunberg, 17, who over the years has emerged as the global climate ambassador, said her calls to the corporate elite meeting in Davos to disinvest immediately in fossil fuels were ignored.
Asked for her impressions of the event, a clearly underwhelmed Thunberg was to the point, saying "We had a few demands (coming into the World Economic Forum)".
At the news conference, Thunberg sought to share the spotlight, deferring to her fellow activists: Vanessa Nakate of Uganda, Loukina Tille of Switzerland, Luisa Neubauer of Germany, and Isabelle Axelsson of Sweden. Thunberg fired back at the comment Mnuchin made at the Davos Economic Forum when he said that the environmentalist needs to get back to school and study economics, before urging the global community to stop investing in fossil fuels that climate activists believe are the main driver of climate change. "That doesn't work. The only way it works is to tell stories and to get to people's hearts, and some of these young people I know have such incredible stories, and they really are changing the way people think", Goodall said in an interview Thursday.
"From the first day onward, we striked for actual climate action", she added.
Asked about Mnuchin's comments, the Swede said: "Of course it has no effect".
The CEO of Siemens said he had told Trump he needed to start listening to young activists.
"At the moment there is an insane focus on climate activists, on people".
On Friday, Thunberg, who has been battling the flu this week, apologized for her "low energy" - a term Trump has often used to mock rivals - as she spoke out again in favour of science and facts, and set off on yet another "Fridays for Future" march through snowy Davos streets.