Hundreds of climate scientists, thousands of research studies, eight years of work – building on more than three decades of research before that – have been boiled down in the past fortnight to a single message: we are running out of time.

Extreme weather is taking hold in every part of the planet, the atmosphere and seas are warming at rates unprecedented in human history, and some of the consequences are irrevocable, according to the sixth assessment report of the Intergovernmental Panel on Climate Change (IPCC), published on Monday.

Only drastic cuts in greenhouse gas emissions this decade can prevent us from raising global temperatures to a disastrous extent, the scientists have concluded.

The IPCC is the body of the world’s leading climate experts, formed in 1988 and charged with preparing comprehensive reports on the state of our knowledge of the climate.

Its first report in 1990 warned of the potential consequences of rising greenhouse gas emissions, and was key to the forging two years later of the UN Framework Convention on Climate Change, the parent treaty to the 2015 Paris agreement.

Since then, reports have been produced roughly every seven years, with Monday’s the sixth assessment report. Only the first part, dealing with our knowledge of the physical basis of climate change – the core underlying science – was published on Monday. Two further instalments, on the impacts of the climate crisis and on ways of reducing those impacts, will follow next year.

Each report runs to thousands of pages, representing the full spectrum of human knowledge of the climate system, but is reduced to a few key messages called a summary for policymakers (SPM), in a fortnight-long meeting of scientists. Under the rules of the IPCC, which was co-founded by the UN and the World Meteorological Organisation, governments also play a key role at this stage and can temper the findings of the SPM.

That has led to criticism in the past, as some scientists have charged that the messages have been toned down, and new science such as concerns over tipping points in the climate system have been sidelined. However, it also means governments cannot ignore the findings they have themselves endorsed.

This year’s SPM meeting still lasted a fortnight, but was markedly different from the sweaty all-nighters that characterised previous IPCC reports. Instead of meeting in person, scientists had to log in from around the globe to online sessions, because of the Covid-19 pandemic.

At previous IPCC meetings, the lead scientists would emerge, rumpled, unshaven – the leaders were almost always men – and exhausted, waving handwritten notes to announce their conclusions. This time, the process was managed via video calls and electronic meeting systems.

It was still exhausting. Paola Arias, an associate professor at the University of Antioquia in Colombia, and an IPCC lead author, says: “We were collaborating around the world, which was good as it meant we could all talk, but meant with the different time zones usually someone would have to get up at 2am or 3am to start while another was at the end of their day.”

Joeri Rogelj, the director of climate research at the Grantham Institute, Imperial College London, rushed out to buy food after briefing the world’s media on Sunday. “My cupboards are bare; I haven’t managed to get any shopping in a fortnight,” he said.

After this report is completed next year, the IPCC process will continue. Researchers will submit papers for peer review and publication in scientific journals, and the IPCC’s lead authors will pick the most significant for further investigation and inclusion in a seventh assessment report, likely to be published towards the end of this decade.

There will be one stark difference between this report and the next, however: this is the last IPCC report to be published while we still have a chance of averting the worst ravages of climate breakdown.