Cocoa husks help counter climate change

In Germany, the substance, dubbed biochar, is produced by heating the cocoa husks in an oxygen-free room to 600 degrees Celsius.

The process locks in greenhouse gases and the final product can be used as a fertiliser, or as an ingredient in the production of "green" concrete.

While the biochar industry is still in its infancy, the technology offers a novel way to remove carbon from the Earth's atmosphere, experts say.According to the UN's Intergovernmental Panel on Climate Change (IPCC), biochar could potentially be used to capture 2.6 billion of the 40 billion tonnes of CO2 currently produced by humanity each year. But scaling up its use remains a challenge.