"By overexploiting the Earth’s natural resources, humanity is not putting nature at risk, but nature’s provisional capacity to nourish humanity. Humanity is putting itself at risk. It is highly unlikely that in 2050 nine billion people can live in a civilisation of economic development and growth as we do today. No massive technological progress can be seen on the horizon that will lower the burden of the energy, farming and fishing levies on the capital of the Earth. The ecosystem in itself is in no way threatened. The Earth still has 4 billion years before it can regenerate all its resources — without mankind! — thanks to the chemistry of carbon, oxygen and hydrogen. A ravaged ecosystem will regenerate itself very rapidly, that is, in less than 100,000 years."