Scientists are poised to deliver a stark condemnation of the damage we are wreaking on the land surface of the planet.
We have degraded soils, expanded deserts, felled forests, driven out wildlife, and drained peatlands.
In the process, we have turned the land from an asset that combats climate change into a major source of carbon.
The scientists will say we must stop abusing the land if we hope to avoid catastrophic climate heating.
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How can the land protect us from climate change?
Uncultivated land covered with vegetation protects us from overheating because the plants absorb the warming gas CO2 from the air and fix it in the soil.
But the scientists meeting in Geneva, Switzerland, will say the way we farm and grow timber often actually increases emissions of carbon dioxide.
Between a quarter and a third of all greenhouse gas emissions are now estimated to come from land use.
The scientists will warn of a battle for land between multiple competing demands: biofuels, plant material for plastics and fibres, timber, wildlife, paper and pulp – and food for a growing population.
Their report will say we need to make hard choices about how we use the world’s soil.
And it will offer another warning that our hunger for red meat is putting huge stress on the land to produce animal feed, as well as contributing to half of the world’s emissions of methane – another greenhouse gas.
What is the report?
The document’s being finalised this week among scientists and government officials on the UN's Intergovernmental Panel on Climate Change (IPCC).
It will become the most authoritative report yet on the way we use and abuse the land. Scientists hope it will give the issue of land use greater prominence in negotiations on climate change.
At its heart will be the paradox that the land can be a source of CO2 emissions, or a sink for CO2 emissions.
The question is how we use it.
Why is that an issue?
Take the fenlands in the east of England – a huge expanse of lowland peat.
In its natural state, it’s saturated with water. But over centuries, 99% of it has been drained for farming. Food crops don’t grow in peat bogs.
The remaining un-drained 1% is Wicken Fen, a plot owned by the charity the National Trust, where the soft black soil is still 4m deep.
The surrounding drained farmland is noticeably lower, because as it’s been drained the peat has shrunk to just 50cm thick.
Between 1-2% of the soil on the drained farmland is still being lost every year./BBC news