The world is still on track for a catastrophic 2.6C increase in temperature as countries have not made sufficiently strong climate pledges, while emissions from fossil fuels have hit a record high, two major reports have found.

Despite their promises, governments’ new emission-cutting plans submitted for the Cop30 climate talks taking place in Brazil have done little to avert dangerous global heating for the fourth consecutive year, according to the Climate Action Tracker update.

The world is now anticipated to heat up by 2.6C above preindustrial times by the end of the century – the same temperature rise forecast last year.

This level of heating easily breaches the thresholds set out in the Paris climate pact, which every country agreed to, and would set the world spiralling into a catastrophic new era of extreme weather and severe hardships.

A separate report found the fossil fuel emissions driving the climate crisis will rise by about 1% this year to hit a record high, but that the rate of rise has more than halved in recent years.

The past decade has seen emissions from coal, oil and gas rise by 0.8% a year compared with 2.0% a year during the decade before. The accelerating rollout of renewable energy is now close to supplying the annual rise in the world’s demand for energy, but has yet to surpass it.

“A world at 2.6C means global disaster,” said Bill Hare, CEO of Climate Analytics. A world this hot would probably trigger major “tipping points” that would cause the collapse of key Atlantic Ocean circulation, the loss of coral reefs, the long-term deterioration of ice sheets and the conversion of the Amazon rainforest to a savannah.

“That all means the end of agriculture in the UK and across Europe, drought and monsoon failure in Asia and Africa, lethal heat and humidity,” said Hare. “This is not a good place to be. You want to stay away from that.”

The world has already heated up by about 1.3C since the Industrial Revolution due to deforestation and the burning of fossil fuels, a situation that has already unleashed fiercer storms, wildfires, droughts and other calamities.

Under the Paris deal, signed in 2016, countries are meant to periodically update their plans to slash emissions, with new submissions of so-called nationally determined contributions (NDCs) expected for this round of UN climate talks currently under way in Belém, Brazil.

But only about 100 countries have done so, with the cuts envisioned very much insufficient to address the climate crisis.

Under a scenario that considers countries’ net zero targets as well as NDCs, the outlook has slightly worsened, with global heating moving from 2.1C to 2.2C by the end of the century, according to the Climate Action Tracker, largely because of the US’s withdrawal from the Paris climate deal.

Donald Trump has called the climate crisis a “hoax”, torn up climate policies at home and agitated for more oil and gas drilling in America and overseas. For the first time, the US has not sent a delegation to a Cop summit, to the relief of some delegates.

While the rate of global heating is still dangerously high, the expected levels have come down since the Paris deal, when about 3.6C of heating by 2100 was expected. This is due to an explosion in the rate of clean energy deployment and a decline in the use of coal, the dirtiest of fossil fuels.

However, an assessment released simultaneously by the Global Carbon Project (GCP) found emissions from fossil fuels are still projected to rise by about 1% in 2025.

The new analyses also show a worrying weakening of the planet’s natural carbon sinks.

The scientists said the combined effects of global heating and the felling of trees have turned tropical forests in southeast Asia and large parts of South America from overall CO₂ sinks into sources of the climate-heating gas.

There was a global agreement to “transition away” from fossil fuels at Cop28 in Dubai in 2023, but the issue is always contested at the UN meetings.

On Tuesday, the G77 group of nations plus China, representing approximately 80% of the world’s population, announced support for an agreed process at Cop30 to support a just transition away from fossil fuels – though other countries (including Australia, Canada, Japan, Norway, the UK and the EU) did not support it.

Brazil has established an investment fund to tackle deforestation, but many countries, including the UK, have not signed up to it.

Former US vice-president Al Gore told delegates that it is “literally insane that we are allowing [global heating] to continue”.

“How long are we going to stand by and keep turning the thermostat up so that these sort of events get even worse?” he said.

“We need to adapt as well as mitigate, but we also need to be realistic that if we allow this insanity to continue, to use the sky as an open sewer, that some things will be very difficult to adapt to.”

Prof Corinne Le Quéré of the University of East Anglia, one of the 130 GCP scientists, said: “We’re not yet in a situation where emissions are going down as rapidly as they need to to tackle climate change, but at the same time emissions are growing much less rapidly than before because of the extraordinary growth in renewable energy.

“It is clear that climate policy and actions work – we are able globally to bend these curves.”

She said 35 countries, representing a quarter of the global GDP, now have growing economies but falling emissions. This has been the case in Europe and the US for some years, but these nations have now been joined by Australia, Jordan, South Korea and others.

The report projects that the level of CO₂ in the atmosphere will reach 425ppm (parts per million) in 2025, compared with 280ppm in the preindustrial era. It would have been 8ppm lower if the carbon sinks had not been weakened.

The GCP projection for 2025 is based on monthly data up to September and has proven accurate in the previous 19 annual reports.

Romain Ioualalen, at Oil Change International, said: “The countries meeting at Cop30 need to double down on renewable energy and start planning for an accelerated phaseout of fossil fuel production and use.”