It will come in the form of a prediction for future sea-level rise in a landmark report on global warming by the world’s climate scientists. On current trends, anything more than three generations will feel like a reprieve.

On the packed streets of Male’, the mini-Manhattan that serves as the Maldives’ island capital, there is a political clamour. But, perhaps surprisingly, the cause is not worry about the existential threat posed by the rising seas but over accusations of corruption and vote-buying in the presidential election.

Friday’s landmark report on global warming from the Intergovernmental Panel on Climate Change (IPCC) – which is currently being finalised by a meeting of the world’s top climate scientists along with political observers in Stockholm – will set out the extreme precariousness of this position.

For coral reefs, the 800 climate scientists behind the report will be forced to add a new colour – purple – to the top of their range of risk levels to signify how much the dangers have worsened since the last IPCC assessment in 2007.

A significantly higher estimate for future sea-level rise is expected, up to 97cm by 2100, and this poses the most obvious threat to an archipelago where most land is no taller than an 11-year-old child. But rising sea temperatures will also increase coral bleaching and crumbling – where the reef gradually dies because the coloured algae that live within and help to feed the corals are expelled as the water warms.

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