This is one of the worst methane leaks ever recorded. Thousands of tons of methane were pumped into the atmosphere after a blowout at an exploration well in Kazakhstan last year. The leak lasted for six months. The impact on the planet was similar to that of more than 700,000 petrol cars over a year. Methane is one of the main contributors to global warming. It's a greenhouse gas much more potent than carbon dioxide. Busachi Neft, the company that owns the Exploration Well, denies a substantial amount of methane was leaked. Methane is invisible to the naked eye. But when sunlight passes through a cloud of the gas, it creates a unique fingerprint that some satellites are able to track. This particular methane leak was investigated and verified by scientists across Europe who concluded that 127,000 tons of methane escaped from this single well.