Hydrocarbon exploration, or oil and gas exploration, is becoming increasingly common in the Arctic. The Arctic accounts for around 13 % of the undiscovered oil, 30 % of the undiscovered natural gas, and 20 % of the undiscovered natural gas liquids (see LNG definition) in the world. Because of the harsh conditions present in the Arctic, extracting these hydrocarbons is hugely expensive using conventional means. To make extraction cheaper, oil companies are investing in floating LNG production systems (see LNG definition). Extraction is still significantly more expensive in the Arctic than in a Saudi Arabian desert, for example, but the large reserves in these more conventional sources have been used up, and is still economically viable due to the rising value of fuel. There are multiple risks associated with hydrocarbon exploration in the Arctic: There is no effective method for clearing up an oil spill in ice-infested waters, for example, an oil spill would be devastating to the pristine Arctic biodiversity (see definition).