The UK is pushing hard ahead of the COP26 climate summit for all countries to support the goal of zero emissions by 2050. It is necessary to achieve the goal of a maximum 1.5 degree temperature increase according to the UN climate panel.
And many countries already have net zero targets by 2050, they represent about 70 percent of the world economy.
The goal has seemed uncontroversial.
But now a proposal from a group of 24 "like-minded" developing countries has made the 2050 goal a new issue at the climate summit.
India is dominant, but also China, Indonesia, Egypt, Saudi Arabia and Vietnam are among the countries that now write that such a goal is increasing the gap between rich and poor countries and stopping their right to economic development.
They believe that the goal is a "global goal" that can not apply to all countries.
The rich countries must do more instead.
"Large, developed countries are now pushing to move the pillars of the Paris Agreement from what we agreed on earlier ... this new 'goal' is against the Paris Agreement and climate justice."
"Must leave space in the atmosphere"
The rich countries have not only betrayed promises of climate aid, and to live up to their own emission reductions before 2020, according to developing countries.
They also accuse the rich countries of not looking at their historical debt in emissions.
Developing countries believe that they are entitled to what is left of the shrinking coal budget.
"In the light of historical emissions, rich countries must leave the remaining space in the atmosphere for the developing countries' right to economic development and aim for total fossil freedom within ten years."
The Paris Agreement is based on a "common but different responsibility" for rich and poorer countries, but the proposal instead strengthens the gap at a critical stage before COP26.
China has a goal of being climate neutral by 2060, but has still signed the letter.