The mainland will face a critical shortage of key resources - including oil and gas - within 20 to 30 years, increasing the nation's reliance on imports, a report warns. 'Except for coal, we are already in an emergency with all major mineral resources,' said Wang Anjian, director of the China Geological Science Academy's mineral resources research unit. 'I was very surprised by the results. This is very dangerous for China's security.' The report took two years to prepare and has been sent to the top departments of the government, including the State Council, the State Development and Planning Commission and the State Economic and Trade Commission. By 2020, the country will have to import 500 million tonnes of crude oil, accounting for 70 per cent of its consumption, and 100 billion cubic metres of gas, 50 per cent of its needs, it said. By comparison, imports of crude oil last year amounted to about 65 million tonnes, accounting for about 30 per cent of consumption. The report forecast that during the next 20 years, the country would face a shortage of three billion tonnes of iron, 500 to 600 million tonnes of copper and 100 million tonnes of aluminium. It may also face shortages of other minerals, of which it is currently a major producer and exporter, such as tungsten and tin. 'Because of chaotic mining and excessive exports, absolute reserves have fallen by 33 to 50 per cent. Current levels of production cannot be sustained for more than 10 years,' the report said. Dong Shuwen, vice-president of the agency, said the authors of the report hoped that the country's political, economic, diplomatic and defence policies would take resource security into account. Mr Wang said the nation would have no choice but to rely on the global market for its mineral requirements. 'Japan and South Korea are two countries with few natural resources and they depend on the world market. No country is self-sufficient,' he said. 'Our goal of quadrupling 2000 GDP by 2020 is attainable, but we cannot follow the high-energy-consumption model of some Western countries. 'We must make full use of coal.' The report said the nation had proven coal reserves of 81.8 billion tonnes and would consume 24.7 to 26.8 billion tonnes during the next 20 years. Mr Wang said oil would be the tightest commodity. The report said China's main oil fields were nearing the end of their productive life.