Offshore northern Alaska, mean estimates by the same groups peg discovered but undeveloped oil reserves at 1.2 billion barrels and undiscovered reserves at 8.6 billion barrels. With potential topping 25 billion barrels, Alaska should be one of the cornerstones of future US oil production. Whether it will depends largely on the outcome of the political debate currently raging between environmentalists and oil and gas development proponents over exploitation of the Arctic National Wildlife Reserve (ANWR), estimated to hold at least 11 billion barrels of oil.