World leaders welcomed chinas new climate target in addresses to the un general assembly on thursday, and said the year ahead would determine the fate of the paris climate agreement.

Boris johnson, the uk prime minister, called on other heads of state to commit to new climate targets this year, following the net-zero emissions goal it adopted last year. the uk aspired to be the saudi arabia of wind power, he said. it is already the worlds biggest centre for offshore wind power.

Humanity was caught napping by coronavirus, mr johnson said. but for this thing, for climate change, nobody can say that we have not been warned. and nobody can say that we are not now capable of making the preparations.

Despite the pledges, young protesters led by greta thunberg are planning to take to the streets on friday in thousands of cities around the world, in the biggest demonstrations over climate change since coronavirus lockdowns began.

We are in a global emergency that affects all of us, said the 17-year-old activist at a press conference last week. ms thunberg recently returned to secondary school full time but has called for a youth strike from school on friday.

At a time when coronavirus has postponed many countries climate plans, and as wildfires take a devastating toll from the west coast of the united state to siberia, the new pledges made at the un general assembly have put climate change back in focus.

The year ahead of us will determine the fate of the paris climate agreement, said ursula von der leyen, president of the european commission.

She outlined the ways in which the eu was tackling climate change as part of its 750bn recovery resilience fund, including raising 200bn through green bonds, a first for the eu.

She also praised chinas vow to achieve carbon neutrality, saying she was encouraged by president xi jinpings announcement.

Chinas pledge to become carbon neutral by 2060, announced on tuesday, will represent the biggest reduction in emissions of any country if it can be achieved. the new target will lower global warming projections by 0.2c-0.3c, according to climate action tracker, a non-profit research group.

The uk and italy were due to host the next un climate summit, known as cop26, in glasgow this november. but it has been delayed by a year because of the coronavirus.

A major challenge for the talks is that the us the worlds second-largest emitter of greenhouse gases is planning to formally withdraw from the paris climate accord in november.

Donald trump, us president, called the agreement one-sided, when he addressed unga this week, and accused china of dumping plastic into the ocean.

Global emissions are expected to fall this year because of the economic contraction caused by coronavirus. however, the carbon dioxide already in the atmosphere has contributed to record-breaking temperatures in recent months, including the hottest summer ever recorded in the northern hemisphere.