President Biden has pledged to direct $11 billion annually toward international climate aid by 2024, quadrupling the previous U.S. high-water mark.

It is something that Biden has raised repeatedly in speeches to other world leaders, including during the United Nations General Assembly in September.

"To meet our global responsibility, my administration is working with our Congress to deliver more than $11 billion a year to international climate finance," Biden said then, "to help lower-income countries implement their climate goals and ensure a just energy transition."

When Biden speaks about U.S. efforts to cut carbon emissions at the UN climate summit, COP27, in Sharm el-Sheikh, Egypt on Friday, Biden will reiterate that he wants to "help the most vulnerable build resilience to climate impacts," White House press secretary Karine Jean-Pierre told reporters.

But it remains unclear whether the president will be able to meet his goal — particularly if Republicans make gains in midterm elections this week — because Congress has been reluctant to spend as much money as Biden has asked for.

What is the purpose of international climate aid?

At past international climate summits, like the one Biden will attend this week, developed nations agreed to help less-developed and more vulnerable nations adapt to life on a hotter planet. Developed nations are historically the biggest emitters of greenhouse gasses , while developing nations have contributed very little to the planet's warming but are bearing the brunt of damages from at hotter, more unpredictable climate. This type of aid and investment is often referred to as "climate finance."

The United States is the world's largest economy and largest cumulative emitter of greenhouse gas pollution. It has done more over time to warm the planet than any other nation, although China now emits more on a per-year basis.

How much does the U.S. government spend on helping other countries fight climate change?

The United States, like other countries, is required to submit a report every two years to the United Nations documenting progress on its climate goals. The Trump administration did not file those reports for 2018 or 2020.

A retroactive report, submitted by the Biden administration last year, said that the U.S. invested an average of $2.2 billion dollars yearly between 2015 and 2018 toward international climate finance.

As for what the U.S. has contributed to climate finance under Biden, the totals haven't been officially tallied, but the portion appropriated by Congress has gone up during his tenure.

In March of this year, Democrats in Congress passed a budget that allocated about $1 billion dollars to international climate aid efforts — $387 million more than the same budget items during the Trump administration, though far short of the $2.5 billion the White House had asked for, and many times less than Biden would need to meet his larger pledge.

How much should the U.S. be spending on climate change aid?

At a UN conference in 2009, 12 of the world's largest economies — including the United States — pledged to collectively mobilize at least $100 billion each year to international climate aid by 2020 from public and private sources.

That pledge has never been met — and the countries have now extended the goal to 2025.

In 2020, the most recent year for which complete data is available, developed nations mobilized roughly $83 billion toward climate finance, a mixture of both government grants and loans as well as private dollars.

Compared to the other countries involved, the U.S. invests a lot of money in terms of total dollars, but a comparatively small amount relative to the size of its economy.

An analysis from the World Resources Institute, which works to advance international climate action, estimates that a "fair share" for the U.S. of the big economies' $100 billion pledge would be somewhere between $40 billion and $47 billion annually, taking into account the size of its economy and its historic contribution to global warming.

The $11 billion in annual climate finance aid that Biden has promised — and the $100 billion that the United States has pledged collectively with other world economies — would be a major resource to help the poorest nations adapt to and mitigate damages caused by a warming planet.

Advocates see it as a good-faith commitment, a sign that the U.S. and other major emitters are taking the problem seriously.

But as a UN report laid out earlier this month, the pledge still is many times lower than the full amount needed to tackle the immense, global challenges posed by the climate crisis.

Where would the money for Biden's climate pledge come from?

The administration has two main sources of funds it hopes to draw from: appropriated funding from Congress, and money from federal development agencies.

The White House would like Congress to provide $5.3 billion, or roughly half the total pledge, to help specific countries and to support large, international efforts like the Green Climate Fund.

Administration officials hope the second half will come from sources like the Export-Import Bank and the International Development Finance Corporation (DFC), government agencies that use financial instruments like loans and insurance to advance U.S. policy goals abroad.

Congress isn't keen on Biden's $11 billion promise

The first — and most immediate — hurdle that Biden faces is Congress. Passing any funding bill requires 60 votes to clear the Senate. That means Democrats need to convince some Republican lawmakers to join them.

The White House asked Congress for $5.3 billion in funding in its 2023 budget request in March, which would be enough, in combination with anticipated development finance money, to meet the president's pledge. But it is a big jump from what Congress has done in the past — roughly five times what it allotted for 2022.

Wyoming Senator John Barrasso, the top Republican on the Senate Energy and Natural Resources Committee, denounced the White House's proposal as "another pipe dream of liberal activism and climate extremism."

And since the budget was released in the spring, the headwinds facing the administration have only gotten stronger. Inflation has remained stubbornly high, and some economists worry that interest rate hikes from the Federal Reserve could lead to a recession.

That would mean that adding billions in international climate aid could be a tough pill for some lawmakers — even some Democrats — to swallow.

Biden also hopes to tap development agencies for climate funds

Government development agencies are another source of money for Biden's pledge. The government invests in projects abroad through agencies like the Export-Import Bank and the International Development Finance Corporation, which lend out money and look to generate a return on their investments.

The Export-Import Bank and DFC support their work largely through the fees and returns they make on their loans and other programs, rather than through money they receive from Congress.

It's possible that these agencies could scale up their spending on climate-focused programs to help meet the president's pledge, according to Bella Tonkonogy of the Climate Policy Initiative, a nonprofit policy research organization.

But Tonkonogy warned that it isn't just about whether the government can find the money. There is also the question of whether these agencies can quickly identify and vet quality projects.

"That will require working differently — from developing comprehensive climate strategies, to building up staff capacity, to partnering with other agencies," Tonkonogy said.