President Obama is poised to pledge around $3 billion to help the world’s most vulnerable countries adapt to climate change. That sounds like a lot. But is the US set to pay its fair share?

The US’s contribution will be the largest yet to the UNFCCC’s Green Climate Fund (GCF). Such pledges are seen as critical in the run-up to next year’s international negotiations to formulate a new global climate deal. Negotiators hope Obama’s promise will encourage other countries to make similarly bold contributions.

We take a look at who’s pledged what so far, and whether countries are offering their fair share.

Green climate fund

The GCF was established at the Copenhagen climate summit in 2009. But it has been struggling for funds.

World leaders have promised to eventually contribute $100 billion a year to the GCF by 2020. The GCF originally aimed to get countries to pledge $15 billion by the end of this year. It lowered the target to $10 billion this September.

The GCF is politically important. It is the most high profile mechanism that allows developed countries to transfer funds to more vulnerable states. Many of the nations set to receive funds from the GCF have said they can’t commit to cutting emissions unless developed economies honor their promise to contribute to the fund.

Countries are due to make formal pledges at a conference on November 20th. But some have announced their contributions early in the hope of encouraging other governments to pledge.

Unsurprisingly, there’s a big difference in the size of the pledges. The US’s contribution will be much larger than those countries with smaller economies and emissions, such as Sweden and Denmark.

Fair shares

But are governments contributing their fair share?

It’s a complicated question. What counts as a ‘fair’ contribution is ultimately subjective. There is some precedent for states making contributions to similar funds, however.

Oxfam has looked at ways to divvy-up contributions to the GCF among nations, taking account of each country’s historical contribution to climate change and their current capacity to finance climate action.

Oxfam takes an average of countries’ contributions to comparable funds, such as the Global Environment Facility (GEF), Fast Start Finance (FSF), or the United Nations’ overall budget, to estimate how much each country might be expected to give towards the GCF’s initial goal. Oxfam’s calculations were for the GCF’s original $15 billion goal, we’ve adjusted them for its new $10 billon target.

As you can see, the US pledge may be the biggest so far, but is less than Oxfam suggests it should contribute. Even the upper end of Obama’s expected pledge, $3 billion, would be slightly short of the amount Oxfam calculates. It suggests the US’s contribution should be the biggest because it’s the world’s largest historical emitter and economy.

Oxfam’s fair share calculations suggest Germany and France are paying slightly more than they should be. Germany has pledged £1 billion, while Oxfam suggests its fair share is closer to $880 million. France has pledged the same amount as Germany, though its fair share is less: around $700 million, according to Oxfam.

Sweden is the biggest outlier, pledging $500 million. Oxfam’s calculations suggests its fair share is closer to $120 million.

Pledging politics

So why do some countries pay more than their supposedly fair share, while others seem to be skimping?

Countries consider a number of things when deciding how much to pledge, Kiri Hanks, Oxfam’s climate policy adviser tells Carbon Brief.

To start with, leaders have to consider the size of the pot their country’s contribution can be drawn from. Some governments, like the UK’s and Germany’s, have large budgets for international climate finance, so they can potentially pledge large amounts safe in the knowledge the funds are available.

In contrast, President Obama will have to secure the funds from Congress. So he can only pledge an amount he’s confident the US’s generally obstructive legislature will agree to give.

It also depends how much value each country pins on getting a new global climate deal next year, Hanks says. Getting the GCF up and running is vital to a new deal’s prospects, so climate leaders such as Germany have pledged early to try and galvanise others to do the same.

That’s why most of the countries that have pledged so far have done so at big international summits.

France, Denmark, South Korea, Norway, Switzerland, the Czech Republic and Mexico all made pledges at the UN secretary general’s climate summit in New York last month. Obama has chosen the G20 meeting in Australia this week to make his announcement. Hanks explains:

“These are the kind of international moments that get recognition and they’re the moments when you have all the other leaders around the table as well. So it’s an opportunity to put pressure on other people”.

Judging contributions

Most countries are yet to formally announce their contributions to the fund, including big actors such as the UK. All eyes will turn to the remaining countries at next week’s pledging conference.

Obama and the other countries that have already announced their contributions will hope their early pledges will encourage other countries to contribute their fair share. Awash in the expected flood of contributions, Oxfam’s analysis should help to assess whether that’s the case.

Once the pledges have been made, governments have to deliver the funds. The GCF’s accounts show just $13 million has been paid so far. That’s enough to get the fund going, but it’s a long way from the $100 billion a year developed countries ultimately promised to provide.

Main image: Christiana Figueres and Manuel Pulgar-Vidal at the Lima climate conference. © H.E. Mr. Sam K. Kutesa/Flickr.