This list is based on the CIA World Factbook (when no citation is given).[1] or other authoritative third-party sources (as cited). Based on data from EIA, at the start of 2021, proven gas reserves were dominated by three countries: Iran, Russia, and Qatar.
There is some disagreement on which country has the largest proven gas reserves. Sources that consider that Russia has by far the largest proven reserves include the US CIA (47,600 cubic kilometers),[2] the US Energy Information Administration (EIA) (49,000 km3),[3] and OPEC (48,810 km3).[4] However, BP credits Russia with only 32,900 km3,[5] which would place it in second place, slightly behind Iran (33,100 to 33,800 km3, depending on the source).
Due to constant announcements of shale gas recoverable reserves, as well as drilling in Central Asia, South America and Africa, deepwater drilling, estimates are undergoing frequent updates, mostly increasing. Since 2000, some countries, notably the US and Canada, have seen large increases in proved gas reserves due to development of shale gas, but shale gas deposits in most countries are yet to be added to reserve calculations.