For as long as there have been international climate talks, Saleemul Huq, a botanist from Bangladesh, has quietly counseled diplomats and activists on the prickliest question: What is owed to countries least responsible for the problem of global warming but most harmed by its effects — and by whom?

Year after year, calls have steadily grown louder for industrialized nations responsible for the greenhouse gas emissions already heating up the planet to own up to the problem — and pay for the damage.

This year, demands for redress have sharpened as climate justice has become a rallying cry, not just from countries in the global south, like Mr. Huq’s, but from a broad range of activists, especially young people, in the United States and Europe. They have peaked in Glasgow: As negotiations close this week, a major point of contention between rich and poor countries is whether the final summit document will acknowledge the need for a separate pool of money to address historic harms.

Known by sterile code words crafted to avoid blame, “loss and damage,” that fund would be separate from money to help poor countries adapt to a changing climate, its proponents have argued. Loss and damage is a matter of historic responsibility and would pay for irreparable losses, such as the disappearance of national territory, culture and ecosystems, they said.

“The term ‘loss and damage’ is a euphemism for terms we’re not allowed to use, which are ‘liability and compensation,’” Mr. Huq said. “‘Reparations’ is even worse.”

The United States, which is the largest emitter of greenhouse gases historically, has long been cool to the idea. But in Glasgow, it signed a statement agreeing to “increase resources” for loss and damage, without committing to anything more specific. The U.S. climate envoy, John Kerry, said Thursday that any agreement on loss and damage would have to shield countries from legal claims. “We’re going to work hard to deal with that issue over here,” he said.

In the real world, beyond the windowless chambers where negotiators are arguing over the words of the final document, three factors have made it harder to ignore the demands for loss and damage money.

Courts around the world are already hearing liability cases against governments and fossil fuel companies, and in some cases ruling against those governments and companies for the damages they have already caused.

Second, it has become impossible for leaders of wealthy countries to ignore big ticket losses and damages when extreme weather events exacerbated by rising temperatures are taking a toll in their own countries, including record wildfires this year in California and floods in Germany.