Far from the standing ovation delivered by delegates in Dubai, activists in some of Asia's most climate-vulnerable nations responded to the COP28 agreement with disappointment on Thursday.

The deal, approved by nearly 200 countries on Wednesday, contains their first call for a transition from fossil fuels, language hailed by US President Joe Biden as a "milestone".

Lavetanalagi Seru, a Fiji-based climate activist, acknowledged the language was "an incremental step in the right direction".

However, "it falls short of climate justice and equity for our frontline communities", he said.

It "continues to allow for dangerous distractions and loopholes… which is deeply disappointing".

Representatives from some of the most climate-vulnerable nations in the world — small island states which face inundation by rising seas — were not even in the room when the deal was approved.

Marshall Islands negotiator John Silk described the deal as a "canoe with a weak and leaky hull, full of holes".

"We have to put it into the water because we have no other option."

In Bangladesh, regularly ranked as one of the countries most vulnerable to climate change, activist Sohanur Rahman also worried about what the deal leaves undecided.

"Though we demanded phasing out fossil fuels, they adopted transitioning away," said Rahman, executive coordinator of YouthNet, Bangladesh's largest youth network for climate justice.

"It remains a question as to how they'll implement it. More actions are needed on this. It has many loopholes."

'Not losing hope'

Among the concerns expressed by experts is a lack of clear goals for what countries should do on the move away from fossil fuels and by when.

The language also leaves a role for "transitional fuels" — seen as code for natural gas — and addresses fossil fuel use in energy, not industrial areas such as plastics production or fertiliser.

It also preserves a place for coal power if it is "abated", meaning its emissions are captured or limited by technology — something activists fear will be used as a licence to continue polluting.

"The final outcome of COP28 is not enough," said Mitzi Jonelle Tan, a climate justice activist with Youth Advocates for Climate Action Philippines.

"It is a stab in the back after being promised that this would get us on track for the 1.5C (above pre-industrial levels) limit of safety. It hurts us all."

"We need a just and equitable fossil fuel phaseout that's funded and fair."

The conference declared an early win with the launch of a "loss and damage" fund that will help countries cope with climate disasters.

But there was less detail or money on the table for countries facing growing climate impacts and mounting debts while struggling to pay for energy transitions to meet their climate goals.

Bill Bontigao, a youth climate activist in Albay province in the central Philippines, said the loss and damage deal offered a "glimpse of hope".

But the 24-year-old, who has seen the tide creep closer to his home on San Miguel island over the course of his life, said he was already hoping for more at next year's COP29 in Azerbaijan.

He wants to see "this text to become more ambitious, rather than this kind of language which is so vague for me", he said.

"I'm hoping for stronger language."

"As a climate activist, as a youth, I'm not losing hope but continuously disappointed at what is happening."