NICHOLAS KAMM via Getty Images Elon Musk listens to President Donald Trump speaks during a meeting with business leaders in the Roosevelt Room at the White House in Washington, DC, on January 23, 2017.

Elon Musk spent the last decade building an electric car and solar panel company into a $41.7 billion empire aimed at loosening fossil fuels’ grip on the global economy.

But the billionaire Tesla chief executive said he now supports former Exxon Mobil Corp. CEO Rex Tillerson becoming secretary of state. Senators narrowly voted along party lines on Monday to confirm Tillerson’s nomination.

On Tuesday, Musk tweeted a December editorial from The Economist arguing that Tillerson had “the integrity to talk sense to his boss,” President Donald Trump, who has repeatedly called climate change a hoax invented by the Chinese and threatened to pull out of the Paris climate accord.

“This may sound surprising coming from me, but I agree with The Economist. Rex Tillerson has the potential to be an excellent Sec of State,” Musk wrote in the tweet.

“Rex is an exceptionally competent executive, understands geopolitics and knows how to win for his team,” he added. “His team is now the USA.”

He then said: “I share The Economist’s opinion that he should be given the benefit of the doubt unless his actions prove otherwise.”

Under Tillerson, Exxon Mobil shifted away from its scorched-earth disinformation campaign denying the existence of global warming. During his confirmation hearings this month, Tillerson said he believes in climate change, though he rejected the overwhelming scientific consensus that emissions from burning fossil fuels are the chief cause. Still, in 2009, he publicly backed putting a tax on carbon, albeit as his preference to the cap-and-trade system then being debated in Congress.

Rex Tillerson supports a carbon tax. This is what is really needed to move the needle. https://t.co/6ne01TOzs1 — Elon Musk (@elonmusk) January 25, 2017

Musk, by contrast, may be one of the strongest advocates for climate science in the Fortune 500. His companies depend on it. In November, shareholders gave Musk the green light to merge Tesla, known for its luxury electric vehicles, with SolarCity, the solar energy firm he ran with his cousins. Musk envisions the combined company as a one-stop shop for zero-emissions vehicles, and home electricity and heating systems.

His support for Tillerson may be more political than personal. Musk joined Trump’s economic advisory team last month, along with the chief executives of General Motors, Uber Technologies and other big firms. He met with the newly sworn-in president on Monday to discuss the future of U.S. manufacturing, of which Tesla aims to be a big part. The company is building factories in Nevada and New York.

Sigh — Elon Musk (@elonmusk) January 25, 2017