The world’s largest-ever report on climate change will be published later, highlighting the stark reality of the state of the planet.
The study is conducted by the Intergovernmental Panel of Change (IPCC), a UN group that looked at more than 14,000 scientific papers. The IPCC is a UN body set up in 1988 to assess the science around climate change; it provides governments with the scientific information to develop policies on global heating.
The report will be the most up-to-date assessment of how global warming will change the world in the coming decades.
Scientists have said that it will likely be bad news, with “nuggets of optimism”.
And environmental experts have said it will be a “massive wake-up call” to governments to cut emissions.
Some papers studied by the panel show that some of the changes humans are inadvertently making to the climate will not be reversed for hundreds or maybe thousands of years.
The IPCC’s findings, which will be revealed at a press conference at 09:00 BST, will also be used during a major summit hosted by the UK in November.
The summit, COP26 that the UN runs, is seen as a critical moment if climate change is brought under control. Leaders from 196 countries will meet to try and agree on action.
The last panel was in 2013, and researchers say much has firmed up since then.
Previously, for instance, they were reluctant to ascribe extreme events such as heatwaves and torrential rain to being at least partly down to climate change.
Now in the case of the heatwave in the US in June, they’re confident to say it would have been almost impossible without climate change.
They say the world will continue to get hotter.
It will also get wetter, especially in northern Europe, though droughts will increase too as weather patterns shift.
The panel studied papers showing that sea level would continue to rise for hundreds or possibly thousands of years because of the heat already trapped in the ocean deep.
Research confirms that if politicians can stick to holding global temperature increase down to 1.5C, the worst catastrophes can still be avoided in pre-industrial times.
Experts say the impacts of climate change are far more severe when the increase is greater than 1.5C. So far, global temperature has climbed up to 1.2C above pre-industrial levels.
The Paris climate agreement in 2015 established the goal of maintaining the increase in the global average temperature to no more than 2C and to try not to surpass 1.5C.
As well as updates on temperature projections, there will likely be a strong focus on the question of humanity’s role in creating the climate crisis.
It is expected that this time the IPCC will also outline just how much of an influence humans are having on the oceans, the atmosphere and other aspects of our planetary systems.
One of the most important questions concerns sea-level rise. This has long been a controversial issue for the IPCC, with their previous projections scorned by some scientists as far too conservative.