A new report on the impacts of climate change will likely be the most worrying assessment yet of how rising temperatures affect every living thing.
Scientists and officials will publish their conclusions on 28 February.
The study will focus heavily on regional impacts as well as on cities and coastal communities.
The IPCC carries out these large-scale reviews of the latest research on warming every six or seven years on behalf of governments. This set of three is their sixth assessment report.
Researchers are formed into three working groups that look at the basic science, the scale of the impacts and the options for tackling the problem.
For many major cities and developing countries, the report will highlight that tackling climate change is not about cutting emissions and hitting net zero sometime in the future, but about dealing with far more short-term threats.
"It is always the immediate, that takes precedence. So if you've got to deal with a big influx of migrants, or a massive flood event, that's where the focus is going to be," said Mark Watts, the executive director of the C40 group, a network of around 100 major cities that are collaborating to tackle climate change.
"In the global south, there really aren't any city climate programme funds at the moment. Of those that exist, almost none of them are about adaptation. They're all trying to get poor countries that have relatively low emissions, to reduce their emissions further, not about adapting to the impacts that they're already feeling."
Under the umbrella of the IPCC, scientists working on the report, who all volunteer for this work, review and write up thousands of papers to summarise the latest findings.
They then meet with government officials to go through their findings line by line and, upon reaching consensus, a short summary of their findings is published.
The study will also outline key "tipping points" that are likely to be passed as the world warms - some of which are irreversible like the disintegration of the Greenland ice sheet.
The report will also look at some of the technological solutions to climate change, but is likely to be quite dismissive of efforts to manage solar radiation or even to remove carbon dioxide from the atmosphere.
Overall it will have a much broader focus than just the science of what we can do about climate change.
Adaptation in action
Home to more than 24 million, Lagos in Nigeria is Africa's most populated city - but one that's hugely vulnerable to flooding and sea level rise. Making the situation worse is the problem of rubbish and waste that collects in canals and rivers. Dealing with this issue could be key to helping the city cope with the changes brought about by a changing climate.
"One of the one of the things that needs to change in Lagos to reduce that flooding impact is actually to get a grip of the waste management system," said Mark Watts from C40. "Supportive investing in the city for them to get really strong municipal waste collection, proper household collection, and getting it properly treated is going to solve two things at once."
"The report will talk about social justice more, and it will talk about sustainable development more. It does talk about indigenous and traditional knowledge, not just published Western science," said Dr Stephen Cornelius from WWF.
"This is about the impacts on people and nature, the risks they face and the limits to adaptation as well."
Tussle over words
But as scientists and officials meet virtually to thrash out the final details, a tussle has emerged over the use of a key phrase in the text.
For years, developing countries have been trying to get the richer world to respond within UN climate negotiation to the issue of "loss and damage".
They define the phrase to mean the impacts of climate change that countries cannot adapt to, including severe weather such as major storms but also slow-onset events like sea level rise or desertification. Richer countries have long opposed the concept, fearing they could be held legally and financially responsible for centuries for the disruption caused by historic emissions of carbon dioxide. As a result this issue has become a hugely divisive political issue within global climate talks.
In this new report, the IPCC scientists are seeking to use a slightly amended version of the term, talking about "losses and damages," which they say has a different, less political meaning.
But officials from several richer governments attending the approval session have objected, fearing that if the idea appears in a key report, it will give backing to those countries who want "loss and damage" to be the top priority for international negotiations.
Ultimately this report will stress urgency - that if rapid action is taken on cutting greenhouse gases and spending on helping people adapt to climate change is ramped up, then the worst risks can be avoided.
But this hope has to be measured against the reality of politics, according to co-chair Prof Hans-Otto Pörtner.
"One key message has come out of previous reports - political will, in terms of climate action, is the bottleneck for a sustainable future."