William Nordhaus's comments to The Associated Press on Friday followed Trump's recent dismissal of his own government's report warning of the dire consequences of climate change.
"There will be no forward progress under the Trump administration; I think that's virtually inconceivable," Nordhaus said. "It will be good if it didn't go backwards."
Nordhaus will split the 9 million-kronor ($1 million) prize with another American, Paul Romer, who was recognized for his work on how markets can encourage innovation.
Carbon taxes, which involves the imposition of levies on companies that burn fossil fuel, are criticized as being detrimental to economic growth, according to opponents. And that's a sensitive issue in the wake of the global economic downturn a decade ago.
"Nobody can predict with any accuracy what will happen in a year or two years," he said at a news conference with Nordhaus and the winners of the physics and chemistry Nobels.
"On the other hand, everything in history suggests there will be another decline in output. I think we should expect that there will be additional financial crises."
Two of the chemistry prize laureates said excessive concerns about genetically modified foods and other substances can inhibit mankind from benefiting from developments in the field.
"We've been modifying the biological world at the level of DNA for thousands of years," said American Frances Arnold, citing examples such as new dog breeds. "Somehow there is this new fear of what we already have been doing and that fear has limited our ability to provide real solutions."
"There's a lot more we could do with directed evolution if there weren't regulatory hurdles to doing it," Britain's Gregory Winter said. "If we want to do something about it we'll have to loosen up some of these regimes."
They were named winners along with American George Smith for advances that the award characterized as speeding up evolution of enzymes and proteins.
Arnold was one of two female winners of science Nobels this year. The other, Donna Strickland of Canada, said she sees progress in attracting women to traditionally male-dominated science, engineering and mathematics.
"I think women are going into most of the fields. Physics still lags behind and I don't really know why that is the case; it depends, I think, a lot on whether society looks at physics as something to do," she told the AP. She credited the popular TV program "The Big Bang Theory" as having "helped make physics seem cool."
Strickland, Gerard Mourou of France and American Arthur Ashkin share the physics award for developments in lasers. Ashkin, at age 96 the oldest-ever Nobel winner, was unable to travel to Stockholm for Monday's awards ceremony.
The Nobel Peace Prize will be presented on Monday in Oslo. No winner of the literature prize was named this year.
Jim Heintz in Moscow contributed to this story
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