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果洛翻译公司关键字：life and future prospects for the development of space exploration, the human environment, the system is unlimited.Second, the Earth is a finite universe of stars, from the earth of human survival and development environment, but there are limits. Earth's environment has a relatively extreme, and in the formation of the Earth have their own way and at the end of the limit, it is estimated about 50 billion years or so, will be destroyed with the destruction of the sun. Produce only about 500 million years of human history, the environmental conditions suitable for living organisms is the formation of Earth's evolution over a long period after it appeared, the availability of energy resources and there is the limit. 1996, the global water consumption has reached 6 trillion m3 ... ..., accounting for half the amount of fresh water available, if at the current rate, in another 30 years, human water usage limits can be reached; the world's arable land per capita is only 0.32 hectares was lower than that of demographers A Suowei lower limit of 0.4 hectares; 1993, 4.18 billion hectares of forest area, forest area per capita is only the beginning of the industrial revolution, 1 / 38, and is accelerating decline. According to the 1993 case has been proven, world gold reserves of only 6 million tons, then the amount of more than 2330 tons mined, can be mined for 26 years; silver reserves of only 42 tons, then exploitation of 14,100 tons, can be mined for 30 years. Iron ore reserves of 100 billion tons, annual output 513 million tons, but also exploitation of 188.3 years, which can be mined reserves in China 29 years. Copper reserves of 5.9 million tons, annual output of 9,337,000 tons, but also exploitation of 63.2 years. Lead reserves 130 million tons, annual output of 2.644 million tons, 49.5 years can be mined, which can be mined reserves in China 11.9 years. Tin reserves 10 million tons, annual output of 180,000 tons, but also exploitation of 55.5 years, of which the exploitation of reserves in China but also 29.6 years.
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