Congo basin’s peaty swamps are new front in climate change battle

Stumbling on submerged roots, attacked by bees and wading waist-deep through leech-infested water, the three researchers and their Pygmy guides progress at just 100 metres an hour through the largest and least-explored tropical bog in the world.

The group halt and unpack what looks like a spear, which is plunged over and over again into the waterlogged forest floor. Each time it brings up a metre-long core of rich, black peat made up of partly decomposed leaves and ancient plantlife. The deepest the steel blade reaches before meeting the underlying clay is 3.7 metres.