Advances in technology for extracting [natural] gas from shale and methane beds have quickened dramatically, altering the global balance of energy faster than almost anybody expected. Tony Hayward, BP's chief executive, said proven natural gas reserves around the world have risen to 1.2 trillion barrels of oil equivalent, enough for 60 years' supply - and rising fast. There has been a revolution in the gas fields of North America. Reserve estimates are rising sharply as technology unlocks unconventional resources," he said. The breakthrough has been to combine 3-D seismic imaging with new technologies to free "tight gas" by smashing rocks, known as hydro-fracturing or "fracking" in the trade. The US is leading the charge. Texas A&M University said US methods could increase global gas reserves by nine times to 16,000 TCF (trillion cubic feet). Shale gas is undoubtedly messy. Millions of gallons of water mixed with sand, hydrochloric acid and toxic chemicals are blasted at rocks. This is supposed to happen below the water basins but accidents have been common. Pennsylvania's [environmental authorities] have shut down a Cabot Oil & Gas operation after 8,000 gallons of chemicals spilled into a stream. The claims of BP ... are so extraordinary that we may need to rewrite the geo-strategy textbooks for the next half century.