The world’s largest ever report into climate change will be published soon, setting out the stark reality of the state of the planet.
The study is by the Intergovernmental Panel on Climate Change – a UN group that looked at more than 14,000 scientific papers.
It will be the most up-to-date assessment of how global warming will change the world in the coming decades.
And environmental experts have said it will be a “massive wake-up call” to governments to cut emissions.
The last time the IPCC looked at the science of global warming was in 2013 – and scientists believe they have learnt a lot since then.
In recent years, the world has seen record-breaking temperatures, raging wildfires and devastating flooding.
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.
Alok Sharma, the UK minister who is leading the summit, said at the weekend that the world was almost running out of time to avoid catastrophe – and the effects of climate change were already happening.
