The British ambassador to the U.S. is taking a road trip this week across the Midwest in a borrowed electric Jaguar to meet with states that are maintaining high clean-energy standards even as the Trump administration rolls back federal environmental rules.

"You have to be encouraged by the number of U.S. states which are supporting ambitious climate change targets, and so there is a lot we can still work with here," said Ambassador Kim Darroch. He spoke with CNBC shortly before starting his trip around five Midwestern states to promote American and British cooperation on low- and zero-emission vehicles and other clean-energy initiatives.

Darroch is meeting with several state and city politicians, including Michigan Gov. Rick Snyder, Minnesota Gov. Mark Dayton and Chicago Mayor Rahm Emanuel. He's also touring facilities such as the Argonne National Laboratory, where scientists research new energy technologies.

British companies already employ 150,000 people in the states Darroch is visiting: Michigan, Minnesota, Indiana, Illinois and Wisconsin.

"It is not generally realized just how deeply the U.K. is plugged into these five states," he said. "There are hundreds of businesses literally based across the region, offshoots of major British companies."

Jaguar is lending Darroch its new I-Pace, an electric crossover unveiled in March, for the trip. The vehicle has been billed as a serious competitor to high-end electric vehicles from Tesla.

He said he was disappointed the U.S. withdrew from the Paris Climate Agreement, but says he's optimistic about progress individual states have made.

The U.K. is also still working through negotiations around its decision to leave the European Union, but Darroch said he is confident the country will have a deal this fall. The first priority for the U.K. will be to negotiate its own free-trade deal with the U.S., he said.

"We are disappointed by the administration's decision to impose steel and aluminum tariffs," Darroch told

CNBC. "On the other hand, we were encouraged by the agreement the president reached with the president of the European Commission a few weeks back on negotiating a new free-trade agreement on industrial goods apart from vehicles, and that would be a big step forward."