Bhutan, Panama, Madagascar and Suriname rarely make the headlines at the annual climate conference, lost among the rich nations and major emitters that hog the limelight.

By banding together to highlight their unusual status, they hope to change that.

"Our biggest ask is acknowledgement," Bhutan's Prime Minister Tshering Tobgay told AFP in an interview in Baku where the countries launched their "G-Zero Forum".

"If you don't acknowledge this very important fact, a fact born out of decades of sacrifice... why would any country be serious about achieving carbon neutrality."

Tiny Bhutan has a population of less than 800,000 and has harnessed its Himalayan topography to become a hydropower giant, supplying renewable energy to neighbours like India.

There is not yet any official UN designation for carbon-neutral or negative countries.

But the Climate Watch database from the World Resources Institute says Bhutan emits so little that it contributes 0.00 percent to global emissions.

For years it touted its policy of prioritising "Gross National Happiness" over growth, an approach that has become more challenging as young people desert the country in search of jobs.

"We did not become carbon neutral and negative automatically," said Tobgay.

"It took sacrifices. It still takes sacrifices."

"Should we cut down our forest? Should we strip mine our land?" he asked.

Maintaining carbon-neutrality "is costly. It doesn't just happen automatically."

And even Bhutan's existing economic growth -- based largely on hydropower and agriculture -- is threatened by climate change.

"Our big ask is that other countries pursue net-zero more aggressively," he said.

The COP29 talks are heavily focused on the need to increase climate funding for developing countries, with some demanding an existing annual $100-billion figure be increased 10-fold.

Tobgay said he favoured an "ambitious but realistic" approach.

"You can talk of trillions and it's just going to remain a talking shop, and then we sacrifice the billions that we could have otherwise gotten," he said.

"So let's be realistic."