- The agreement, which is not legally binding, was amended at the eleventh hour after interventions from India and China — both among the world's biggest burners of coal.
- This led to a change in language about fossil fuels; the pact now refers to the "phase down" of coal, rather than the "phase out" of coal, as originally proposed.
- There are fears that a more drastic rise in temperatures will disproportionately affect vulnerable populations such as the world's small island nations which are already being inundated by rising sea levels.
The president of COP26 said Sunday that China and India will need to explain why they insisted a crucial passage of the U.N.-brokered climate deal was changed at the last minute.
"China and India are going to have to explain themselves to the most climate vulnerable countries in the world," U.K. lawmaker Alok Sharma, who led the COP26 negotiations, told the BBC's Andrew Marr.
It comes a day after nearly 200 countries agreed on a deal to try to prevent the worst consequences of the climate crisis, following two weeks of talks in Glasgow, Scotland.
The wide-ranging agreement, which is not legally binding, was amended at the eleventh hour after interventions from India and China — both among the world's biggest burners of coal. This led to a change in language about fossil fuels; the pact now refers to the "phase down" of coal, rather than the "phase out" of coal, as originally proposed.
After initial objections, opposing countries ultimately conceded to the amendment.
"Over the past weeks obviously there were certain countries that did not want to have coal language in this compact," Sharma added.
"But at the end of the day, this is the first time ever that we've got a language about coal in a COP decision. I think that is absolutely historic."
Speaking to CNBC Saturday, however, Sharma admitted there was "certainly more work to be done on this issue."
"When we took on the role of COP presidency, I said very clearly that I wanted us to try and consign coal power to history," he said in answer to a question at a press conference following the deal.
"If, at that time, I'd said to you, that here, towards the end of this year at COP, we would have ensured that all of the biggest economies will be no longer financing international coal projects and we have managed to get the sort of agreement we have here, I think people would have been skeptical."
He added: "There's absolutely progress. Should we be going faster? Of course."
Going into the climate conference, world leaders, campaigners and environmental activists representing those most threatened by climate change called for urgent action to limit global warming to 1.5 degrees Celsius above pre-industrial levels.
There are fears that a more drastic rise in temperatures will disproportionately affect vulnerable populations such as the world's small island nations which are already being inundated by rising sea levels. To drive the point home, Simon Kofe, the foreign minister of Tuvalu, an island in the South Pacific, delivered his speech to COP26 standing knee-deep in the ocean.
Sharma has insisted that the deal agreed at COP26 means a 1.5 degree Celsius rise remains "within reach." However, independent analysis by Climate Action Tracker indicates that the current pledges are not enough. It says that even if all pledges are met, global greenhouse gas emissions in 2030 will be around twice as high as necessary to hit the 1.5 degree target.
This temperature threshold refers to the aspirational target inscribed in the landmark 2015 Paris Agreement. Keeping average temperatures from surpassing this level requires the world to almost halve greenhouse gas emissions in the next 8 years and reach net-zero emissions by 2050. It is critically important to prevent the worst of what the climate crisis has in store.
There has been a mixed response to the COP26 deal so far. Jennifer Morgan, the executive director of Greenpeace International, said via Twitter that it only just manages to keep the 1.5 Celsius goal alive, adding that "a signal has been sent that the era of coal is ending — and that matters."
—CNBC's Sam Meredith contributed to this article.