Since returning to the White House, President Donald Trump's administration has withdrawn the United States from the landmark Paris Agreement for a second time and vowed to focus heavily on fossil fuel extraction.

German Chancellor Olaf Scholz said at a climate conference in Berlin that he "deeply regretted" the United States leaving the Paris climate accord and stressed the "enormous" economic opportunities it is missing out on.

"The global market for climate-friendly key technologies continues to grow rapidly," Scholz told the Petersberg Climate Dialogue.

He said investments in the global energy transition had exceeded the $2 trillion mark, which "corresponds to the volume of the entire global oil trade today".

The meeting's host, Foreign Minister Annalena Baerbock, said economic data contradicted the "old prejudice" that investing in climate protection was "unaffordable".

"We all know that there are spoilers in the world right now who want to prevent" greater climate investments, she told the first major meeting of the year related to the COP30 summit taking place in Brazil in November.

Baerbock added that "today climate protection and economic growth no longer contradict one another".

"Climate protection opens up huge economic opportunities, and we as Europeans want to seize them", she added.

Europe especially wants to work with "companies and countries in Latin America, Africa and other regions around the world," Baerbock said.

"If others, such as the United States, decide to stay out of it, that is their decision."

- 'Renewing economies' -

United Nations Secretary-General Antonio Guterres echoed Baerbock's message, telling the Berlin meeting in a virtual address that "renewables are renewing economies".

"They are powering growth, creating jobs, lowering energy bills and cleaning our air. And every day, they become an even smarter investment."

Baerbock also hailed as "historic" a recent agreement struck in Germany to channel an extra 100 billion euros ($107 billion) to climate measures.

Her Greens, who are set to leave government after faring poorly in February elections, wrung the concession from other political parties in exchange for agreeing to support plans for greater defence and infrastructure spending.

EU climate commissioner Wopke Hoekstra meanwhile warned that the world was living in "tremendously difficult times".

"We're facing problems literally from every direction -- and clearly also in the domain of climate action," he told the meeting.

Beyond the United States withdrawing from climate cooperation, there have also been concerns that the issue is being pushed down the global agenda by national security and economic pressures.

"But there's no alternative," Hoekstra stressed. "Humanity doesn't have an alternative and cannot wait.