Land subsidence 'will affect almost fifth of global population'

Unesco warns of urban centres sinking because of unsustainable farming and groundwater extraction

Subsidence, or the gradual sinking of land, could affect 19% of the world's population by 2040, according to new research funded by Unesco.

If no action is taken, human activity, combined with drought and rising sea levels exacerbated by global heating, could put many of the world's coastal cities at risk of severe flooding.