Tanzania: A burning charcoal issue

At a road block in western Tanzania, miles from anywhere, a uniformed official raises a flagged barrier. Nearby is a spill of black, like an oil slick.

This is one of several checkpoints which have been set up around the country in a half-hearted attempt to curtail the largely unregulated trade of charcoal, widely used across the continent as a fuel for cooking.

The guard on duty has confiscated six sacks. They lean against one another and bleed black dust into the sand.

Over the next 50 miles there are dozens of sacks propped up under trees. These will be loaded up by truck drivers who pay around $4 a bag to sell for up to six times the price in the city.

The guard at the roadblock has clearly opened his hand for "kitu kidogo" - a pay-off from coal traders in search of a quick buck.

The numbers tell the story - according to the Tanzania Association of Oil Marketing Companies, 20,000 bags of charcoal enter the capital Dar es Salaam every 24 hours.

Millions at risk

But the impact of this unregulated coal trade is chilling.

Aid agency Christian Aid estimates that 182 million people in Africa are at risk of dying as a consequence of climate change by the end of the century.

Once, Africa boasted seven million square kilometres of forest but a third of that has been lost