This story has been updated.

On Tuesday, as a key part of his moves to forge a consensus around a Paris climate change agreement, President Obama met with the leaders of countries that did the least to cause the problem and yet have the most to lose — many coastal and small island nations like the Maldives, Fiji, the Seychelles and others.

“I’m an island boy,” the president said, noting that he himself had grown up in Hawaii and Indonesia. But while Obama has expressed sympathy for island nations ravaged by climate change, it’s less clear how far he can go to help them.

These islands, organized as the 39-member Alliance of Small Island States and severely jeopardized by sea level rise, have long tried to strike a difficult bargain in climate change meetings — they want the global temperature goal to be holding warming to 1.5 degrees Celsius above pre-industrial levels, rather than 2 degrees. Given that current climate pledges are widely agreed to overshoot 2 degrees by a considerable margin — and with a finite carbon budget that gets smaller every day — it is not even clear whether this is still possible.

And what’s more, these nations have also coalesced around the position that a final agreement should include a separate “loss and damage” provision. Definitions of what this means vary, but in essence, as a recent report notes, it’s the controversial idea that countries that didn’t do much of anything to cause climate change — but will be severely damaged by it — should receive financial support, including financial assistance, from the countries, like the United States, that are responsible.

“For these countries, their view is that if warming goes much above one and a half degrees, they will have to move. And that has established in this process a moral framework that is clear, and is black and white, and it’s not an analytical exercise the way the rest of this is,” says John Coequyt, director of international programs at the Sierra Club. Coequyt calls the small island nations the “moral center” of the climate process.

Indeed, in recent years more and more countries, going beyond the group of small island nations, have also embraced the 1.5 degree concept and notions of “loss and damage.” Over a hundred now support the 1.5 degree goal, says Tonya Rawe, a senior adviser on food and nutrition security at CARE USA.

Speaking Monday in Paris, Obama had already reached out to the small island nations in advance of their meeting, saying that “climate change is a threat to their very existence.” He said that he would back “risk insurance initiatives that help vulnerable populations rebuild stronger after climate-related disasters.” The president on Tuesday announced $30 million in funding for such initiatives for countries located in the Pacific, Central America and Africa.

Several positions are “sacred” to small island developing states in the climate negotiations, said Senator James Fletcher of St. Lucia, who is the Caribbean island’s minister for public service, sustainable development, energy, science and technology.

These include “1.5 degrees Celsius as a long-term temperature goal” and “recognition of Loss and Damage as a critical issue for [small island developing states], which is more than adaptation, and commits to establishing a mechanism in the agreement to address Loss and Damage in a permanent manner,” Fletcher said by e-mail.

“I think we are open to discussing the details and the terminology, but I think the principles remain, and the responsibility of the rest of the world, particularly, towards the small island countries,” added Dunya Maumoon, minister of foreign affairs for the Maldives, the nation that is chairing the Alliance of Small Island States this year and thus playing a lead role in the talks.

There’s little doubt that substantively, the small island states are correct in their claims — 1.5 degrees is definitely safer, not just for them but for everyone. However, when it comes to sea level rise in particular, it could make a dramatic long-term difference for low-lying nations.

A recent report by the International Cryosphere Climate Initiative, for instance, recently estimated the “threshold for Greenland melt to become irreversible”  to be at 1.6 degrees — after that, they say, the ice sheet would be vulnerable to steadily melting away, with the potential to raise seas by 20 feet if it melted entirely. That would be absolutely devastating to many islands.

Take, for instance, the city of Male, the capital of the MaldivesAccording to a 2001 report from the U.N.’s Intergovernmental Panel on Climate Change, with a 90 centimeter rise in seas, 85 percent of it could be “inundated,” barring costly adaptation measures. (The island has built considerable seawalls, however.) Indeed, the highest elevation in the small island chain, which is home to some 400,000 people but in total area not much bigger than D.C., is just 2.4 meters above present sea level.

And the Maldives aren’t even the most vulnerable of island nations. Also in 2001, the IPCC noted that just 80 centimeters of sea level rise would flood two-thirds of Kiribati and the Marshall Islands.

More recently, the IPCC found in 2013 that expected sea level changes by the year 2100, “superimposed on extreme sea level events (e.g., swell waves, storm surges, El Niño-Southern Oscillation) present severe sea flood and erosion risks for low-lying coastal areas and atoll islands.”

No wonder, then, that small island states are holding out for the sharpest cuts in greenhouse gas emissions — and for remedies for the damages they incur because of climate change that is almost entirely not caused by them.

“I understand why they want all these things, because they really are necessary to their ultimate survival,” said Philip Duffy, president of the Woods Hole Research Center and formerly  part of the White House’s National Science and Technology Council. “But I really don’t see that they’re going to get them.”

Asked what would happen if the nations aren’t able to secure these objectives, Fletcher said it was “too early for us to speak of what we will do if the Paris agreement does not address issues that are critical to the long-term survival of [small island states].”

A particular point of contention is likely to turn on loss and damage. The small island nations feel that this is something quite separate from merely adapting to climate change. They generally argue that it should be its own part of any Paris agreement — and for it to mean financial compensation for losses.

As the Micronesian island of Nauru, representing all of the AOSIS members, argued in 2014, “Financial flows from developed countries for addressing loss and damage in vulnerable developing countries should be new and additional to financing for mitigation and adaptation.”

But the United States doesn’t see it the same way.

“We don’t think there should be separate requirements beyond the $100 billion [a year] committed to” helping developing countries, said Ben Rhodes, deputy national security adviser, on the sidelines of the Paris climate conference. He said the Green Climate Fund could be an additional mechanism for raising private capital for innovation. But White House spokesman Josh Earnest said the United States opposes the idea of damages or reparations for past greenhouse gas emissions.

Paul Bledsoe, an energy consultant and former White House aide dealing with climate issues, said by e-mail that “the U.S. and other developed countries (+ China) have emphatically resisted efforts by developing countries to gain provisions on so-called loss and damage — or what amount to climate reparations.” He said that developing nations attempted to insert language about the issue at both Warsaw in 2013 and Lima last year but were rebuffed.

As a partial alternative to loss and damage, insurance approaches like the one backed by Obama on Tuesday can help deal with climate related damages up to a point, says Pete Ogden, a senior fellow at the Center for American Progress who just wrote a report on the subject. They’re particularly good for dealing with acute disasters like hurricanes.

But the approach may be less suited, Ogden explains, for other situations that small island states may face. “Some are slow onset things. You have slow coral bleaching that wipes out a tourist attraction,” he says. “It could be the center of an economy, and if you don’t have businesses and hotels and everybody coming to spend money, that has long-term economic implications. You don’t really pay for that with a compensation fund.”

Precisely how far rich nations will go to help small islands in Paris — particularly when it comes to the clear danger of rising seas — thus remains to be seen.

Steven Mufson contributed to this report.

Clarification: A previous version of this article stated that “loss and damage” involved “compensation,” citing a report by the World Wildlife Fund to support this definition. Actually, that report defines loss and damage to include “support” to countries that are suffer losses or damage that may include financial assistance, but not as compensation. The article has been clarified accordingly.

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