(Bloomberg) — Sign up here to receive the Davos Diary, a special daily newsletter that will run from Jan. 20-24.President Donald Trump launched a veiled attack on environmental “alarmists” in a speech to business and political leaders in Davos, taking a swipe at the World Economic Forum’s key focus this year.Speaking at the Swiss resort town on Tuesday, Trump invoked those who predicted an “overpopulation crisis” and the end of oil, saying: “These alarmists always demand the same thing, absolute power to dominate, transform and control every aspect of our lives.”He also said: “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 and optimism and action, but to embrace the possibilities of tomorrow, we must reject the perennial prophets of doom and their predictions of the apocalypse.”The World Economic Forum audience included 17-year-old climate activist Greta Thunberg, who brought a stark message to the business elite gathering in Davos: Everybody is talking about climate change, but nobody is doing anything. Trump has mocked Thunberg on Twitter.The forum is sounding alarm bells on climate change. This year and for the first time on record, environmental risks occupy the group’s top five long-term concerns, while corporate executives say they’re increasingly concerned about environmental issues.Trump’s remarks were largely focused on America’s economy as an example to other nations, which he urged to cut regulations and taxes. Trump sought to take credit for a booming economy, repeating his re-election arguments just hours before the U.S. Senate was set to formally start his impeachment trial.“I’m proud to declare that the United States is in the midst of an economic boom, the likes of which the world has never seen before,” Trump said. “We’ve regained our stride, rediscovered our spirit.”Trump recounted how his administration presided over cuts in regulations and taxes, and described low unemployment rates for African Americans and women.Claiming CreditTrump claims credit for overseeing an economy enjoying its longest-ever expansion, with an unemployment rate that fell to a five-decade low after tax cuts and spending increases. The Standard & Poor’s 500 Index, which Trump regularly cites as a marker of success, is up about 25% from a year ago.But his fight with China over trade and other protectionist policies have created uncertainty among businesses, especially manufacturers. Despite last week’s interim trade deal with Beijing, the International Monetary Fund on Monday predicted economic growth will moderate to 2% this year and 1.7% in 2021 from 2.3% in 2019 as fiscal stimulus wanes.In his speech at the Swiss resort, Trump said: “The American dream is back, bigger better and stronger than ever before.” The president repeated his grievances with the Fed, saying it raised rates too quickly and lowered them too slowly.Trump said in his speech that he and Chinese leader Xi Jinping “love each other” even after their fight over trade.“He’s for China and I’m for the U.S., but other than that, we love each other,” Trump said.Meeting LeadersTrump is due to hold bilateral meetings with Iraqi President Barham Salih, Pakistan’s Prime Minister Imran Khan, European Commission President Ursula von der Leyen, Swiss President Simonetta Sommaruga and Nechirvan Barzani, president of the Kurdistan Regional Government, according to the White House. Trump will also meet with the forum’s executive chairman, Klaus Schwab, and has said he’ll meet with business leaders, too. He leaves Davos on Wednesday.This is Trump’s second visit as president to the annual gathering of business chiefs, central bankers and foreign leaders. Hanging over the trip this time, however, is his impeachment trial set to formally begin in the Senate. Trump will almost certainly be acquitted by the Republican majority in the Senate, but the trial may produce surprises.Trump has sought to highlight his trade and economic victories to contrast the impeachment proceedings. He skipped Davos in 2017 out of concern that the well-heeled Davos crowd was the wrong fit for a man elected on a nationalist, anti-elites message. He attended in 2018, then skipped last year amid a government shutdown.Trump and German Chancellor Angela Merkel are the biggest-name political leaders in attendance; Trump has regularly complained that Merkel spends too little on defense, doesn’t do enough in Ukraine and is too soft on Iran’s regime, but won’t meet with her in Davos.Other speakers include teenage climate activist Greta Thunberg, whom Trump has insulted on Twitter. Ukrainian President Volodymyr Zelenskiy, whose phone call with Trump triggered the impeachment process, is also due to attend briefly but not to meet with the U.S. president.Once Trump leaves on Wednesday, the U.S. delegation will be led by Treasury Secretary Steven Mnuchin.Trump’s first Davos appearance in 2018 oscillated between a vintage, raucous version of Trump in meetings with national leaders and business executives and more subdued remarks in his formal speech. He touted his agenda but added: “America First does not mean America alone.”To contact the reporter on this story: Josh Wingrove in Washington at jwingrove4@bloomberg.netTo contact the editors responsible for this story: Alex Wayne at awayne3@bloomberg.net, Justin Blum, Alan CrawfordFor more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.