US President Joe Biden is set to announce the country’s steepest ever emissions cuts, as he hosts 40 world leaders on Thursday for a summit on climate change that will include China’s Xi Jinping and Russia’s Vladimir Putin. Biden is expected to pledge to reduce US greenhouse gas emissions by as much as 50 percent by 2030 relative to 2005 levels, according to people familiar with the administration’s thinking.

That marks a significant acceleration of the Obama administration’s pledge to cut emissions by 26-28 percent by 2025. Ahead of the summit, the Biden administration has launched several new climate policies, including efforts to integrate climate-related risk into the financial system as well as tax credits for clean energy as part of its $2tn infrastructure bill.

Janet Yellen, the US Treasury secretary, said in a speech that climate change had become an “existential risk to our future economy and way of life,” as she vowed to try to catalyze public investments in green energy and private financing of green technologies. “The investment needed to green our economy is enormous,” Yellen said. “One estimate placed the needed incremental investments at over $2.5tn for the United States alone. Private capital will need to fill most of that gap. ”

Since taking office, Yellen has co-ordinated the agency’s efforts on the subject and has vowed to step up efforts to evaluate and disclose climate risks, to facilitate more investment in the sector.

or even do nothing at all. This is completely wrong, in my view. This is a major problem and it needs to be tackled now,” she said.