The UK minister tasked with leading UN climate talks says world leaders are failing to show the necessary level of ambition.
Alok Sharma was speaking at the conclusion of a virtual climate summit organised by the UK, UN and France.
He said "real progress" had been made and 45 countries had put forward new climate plans for 2030.
But these were not enough to prevent dangerous warming this century, Sharma explained.
Taking place on the fifth anniversary of the Paris climate agreement, the virtual meeting heard the UN Secretary General warn that every country needed to declare a climate emergency.
Around 70 heads of state and government took part in the meeting, outlining new pledges and commitments to curb carbon.
China's contribution was eagerly awaited, not just because it is the world's biggest emitter, but because it has recently promised to reach net zero emissions by 2060.
Achieving net zero means that emissions have been cut as much as possible and any remaining releases are balanced by removing an equivalent amount from the atmosphere.
But while President Xi Jinping outlined a range of new targets for 2030, many analysts felt these did not go far enough.
India brought little in the way of new commitments but Prime Minister Narendra Modi said his country was on track to achieve its goals under the Paris agreement and promised a major uptick in wind and solar energy.
According to the UK, some 24 countries had outlined net zero commitments and 20 had now set out plans to adapt and become more resilient to rising temperatures and their impacts.
But despite these commitments, Sharma said not enough had been achieved.
"Have we made any real progress at this summit? And the answer to that is: yes," he said.
"But they will also ask, have we done enough to put the world on track to limit warming to 1.5C, and protect people and nature from the effects of climate change? To make the Paris Agreement a reality."
"Friends, we must be honest with ourselves, the answer to that, is currently: no. As encouraging as all this ambition is. It is not enough."
Earlier on Saturday, UK Prime Minister Boris Johnson said advances in renewable energy technologies would "save our planet and create millions of high-skilled jobs".
He added: "Together we can use scientific advances to protect our entire planet - our biosphere - against a challenge far worse, far more destructive even than the coronavirus. And by the promethean power of our invention, we can begin to defend the Earth against the disaster of global warming."
China's President Xi Jinping reiterated a previous commitment to reach peak CO2 emissions before 2030 and achieve carbon neutrality by 2060.
He announced that China would reduce its carbon emissions per unit of gross domestic product (GDP) by over 65 percent compared with 2005 levels. The country will also increase the share of non-fossil fuels in primary energy consumption by about 25 percent. And President Xi pledged to increase forest cover and boost wind and solar capacity.
But Manish Bapna, executive vice president and managing director of the World Resources Institute (WRI) said: "The strengthened renewable energy, carbon intensity, and forest targets are steps in the right direction, but recent WRI analysis shows that China would benefit more economically and socially if it aims higher, including by peaking emissions as early as possible."
- BBC