Phillip Muller, the Marshall Islands' ambassador to the United Nations, said comparing vulnerabilities is a near-impossible task. But one criterion he said should be paramount is a country's survivability.
"One definition I think we can start off with is to look at countries that would cease to exist if sea levels rise, or if there's a big hurricane or tsunami," said Muller, who fears that his own country of archipelagos will someday disappear beneath the waves.
And Farrukh Iqbal Khan, Pakistan's lead negotiator, who also chairs an adaptation fund board, said he believes countries need to consider the global impact of a catastrophe in a specific country. For example, he said, a struggle over water between Pakistan and India could reverberate worldwide -- but so would helping both nations to adapt.
"We must look at the global co-benefit, how to invest in areas that also contribute to addressing global impacts," Khan said.
Sparring over a dubious achievement
The issue came to a head at a U.N. climate change conference in Cancun, Mexico, last year when the G-77 group of developing nations sparred over who should be included in the definition of "vulnerable."
The 2009 Copenhagen Accord specifically cited least developed countries, small island developing states and Africa as "particularly vulnerable." That, negotiators said, caused unhappiness in Latin America, where leaders felt threats to their region were being ignored. But attempts in Cancun to categorize nations ended in a stalemate, and negotiators ultimately stayed vague, declining to elaborate on who should be included in the definition "particularly vulnerable."
Katherine Sierra, former vice president for sustainable development at the World Bank and now a senior fellow at the Brookings Institution, described the debate over vulnerability as "like a third rail" among developing nations.
But, Sierra said, there are models that new bodies like the Green Fund can look to for experience. The World Bank, for example, has an established formula for International Development Association (IDA) funds that go to the poorest countries that combines income level, institutional capacity, governance and other elements. By contrast, grants that the World Bank has doled out specifically for climate resilience were determined by an outside group of experts working with a set of specific criteria.
The Global Environment Facility, which implements an adaptation fund paid for by taxes on clean energy projects through the Kyoto Protocol, still has not finalized a way to prioritize funding, said Marcia Levaggi, manager of the adaptation fund secretariat. That discussion, she said, is still happening among the country representatives who make up the board.
'We are all in this together'
Heather McGray, a senior associate at the World Resources Institute which also is studying the issue, suggested a sequencing or rotation in which resources are directed to different regions in cycles.
As plans for the Green Fund go forward -- a transition board will meet in Bonn, Germany, in March -- Sierra said she expects discussions about broad categories of financial eligibility. But, she said, she doubts nations are ready to get specific about prioritizing money. "I think it's going to be very difficult politically to get this done," she said.
But for now, some point out, the fight over how to spend the money is almost a moot point. There is no money. The Green Climate Fund established in Cancun, which will manage most of a $100 billion annual pledge that nations have made, is not yet organized. And so far, the financial pledge is unfulfilled. Most countries have not even decided where the money will come from.
Wheeler in his study warned that the world doesn't have long to make choices. One aspect of the research that came through loud and clear, he said, was that climate change impacts are already being felt and there is little time to waste.