The United States on Wednesday announced plans to double the grant funding it provides to help developing countries adapt to climate change to around $860 million a year, a pledge that may help clinch a global climate pact this week.

U.S. Secretary of State John Kerry announced the new financing pledge during a speech at the U.N. climate conference in Paris, where negotiators from 195 countries are working to reach an agreement by this weekend on curbing greenhouse gas emissions beyond 2020.

“We are going to do our part,” Kerry told the audience at the conference in Le Bourget on the outskirts of Paris. “We will not leave the most vulnerable nations among us to weather the storm alone.”

The pledge may help unstick one of the main points of contention at the summit in Paris, where developing nations are pressing for more financial assistance to offset the impact of climate change, such as droughts, flooding and rising sea levels.

The United States and other developed nations have already agreed to jointly mobilize more than $100 billion per year by 2020 for developing countries.

Last year, the United States pledged $3 billion into the United Nations’ Green Climate Fund (GCF), which supports both adaptation projects and clean energy projects to slash emissions, one of the main vehicles to mobilize that money.

A U.S. official said the new grant funding represented a “longer term commitment to expanding focus on adaptation” and build on existing commitments, including the GCF.

The official did not say how the grants would be appropriated, saying only that the funds would come from the State Department and Treasury budgets. It would be distributed through a number of U.S. mechanisms, including USAID.

President Barack Obama had requested $500 million in the 2016 budget for the first tranche of its $3 billion pledge into the GCF but Congressional Republicans opposed to his climate policies have vowed to oppose that spending request.

Heather Coleman, climate change manager for Oxfam, said despite the threats, she thinks Congress will support new funding for adaptation.

“In a hostile Congress, they are already delivering $425 million a year on adaptation,” she said, noting there has been bipartisan support for aid to the most vulnerable countries.

In his speech, Kerry said additional resources from both government and the private sector would need to be raised to help poorer countries, many of which have “contributed almost nothing to this problem in the first place.”

“There are countries for which climate change is an existential threat,” Kerry said. “For them, this isn’t a matter of annexes or peak years – it is a matter of life and death.”