We're not referring to coal. Black gold is a high-grade version of BBQ charcoal that's currently being tested as a way of removing greenhouse gas from the atmosphere for centuries to come.
The charred wood, called biochar, has been sprinkled over farmland in one of the first large-scale trials of its kind, in the hope carbon captured by trees from the air during their lifetime can be buried in the soil. And, better yet, benefit the soil.
The experiment, lead Doctor Tom Bott from England's University of Nottingham, believes the technique could help the UK reach its goal of net zero by 2050. "As a tree grows, it captures carbon from the atmosphere and converts it into wood," says Bott. "Then if we add it (biochar) to the land, we potentially get some benefits to our crops, and we're also sequestering carbon that's important for helping to combat climate change."
If wood rots or burns, it releases carbon back to the atmosphere. But by heating it to temperatures as high as 600C in an oven purged of oxygen, the carbon undergoes a chemical change that locks it up as biochar - often referred to as 'black gold'.
"Once you get that into the soil, it will not degrade," said Dr Bott. "It'll stay there for hundreds, if not potentially thousands of years. It will just continue to persist."
The Allerton Project's research farm is part of the Biochar Demonstrator scheme, funded by UK Research and Innovation, which is testing the feasibility of using the material to remove greenhouse gases from the atmosphere. Farmland, which accounts for 70 percent of the UK land area, is seen as a vast resource for storing carbon.
There is also evidence that when the material is mixed into the soil, it acts as a sponge, storing rainfall and making it available to crops during periods of drought. That could also help make farming more resilient to the changing climate.