We have inherited a single planet. But what have we made of it? The Earth is today an endangered heritage, and the species itself is at risk. UNESCO has just published «Making Peace with the Earth» (Berghahn Books / UNESCO Publishing) the third anthology in the «21st Century Talks» series edited by Jerome Binde. With the collaboration of some 15 leading scientists and experts, such as Paul Crutzen, Nicolas Hulot, Javier Perez de Cuellar, Michel Serres, Mostafa Tolba, Asit K. Biswas and Edward O. Wilson, we offer a future-oriented analysis of the global ecological crisis, together with some proposals for action, which are the substance of this article. Are we fully conscious, even after the latest assessments of the Intergovernmental Panel on Climate Change (IPCC) and the Bali conference, of the colossal challenges that humanity will have to meet, within time frames that have already been overrun? I shall not labor the diagnosis yet again: climate change, desertification, global water crisis, deforestation, ocean degradation, air, soil, water and sea pollution, and the increasing erosion of biodiversity – the picture is all too familiar. The economic and geopolitical consequences of this situation are just starting to be quantified. The cost of our war on the planet is liable to be comparable to the cost of a world war, as the Stern Review points out. There is, moreover, a risk that the war on nature could lead to war in general, given the growing scarcity of fossil fuels and natural resources and the 150 to 200 million eco-refugees anticipated by future studies. Yet what we call problems – starting with climate change – are more in the nature of symptoms. The real problem, in fact, is that of material growth in a finite world, which was identified back in 1972 in the report to the Club of Rome, «The Limits to Growth.» But in 1972, as the report’s joint author Dennis Meadows points out: «Humanity was within its limits, now it is beyond them.» This is borne out by the data on the ecological footprint of the human species calculated by the team of Mathis Wackernagel. In 1972, we had reached 85 percent of these limits. Today human resource consumption stands at about 125 percent of the level sustainable in the long term. So can humanity still be saved? Yes, we can do so, and without preventing the human species from developing and combating poverty. We need to combine growth and sustainable development, rather than seeing them as opposites. But how can this be done? We shall need more knowledge, more restraint, less matter, more concreteness, and more – rather than less – ethics and politics. What this adds up to is another contract, a natural contract and an ethic of the future. More knowledge firstly: There are many who regard techno-science as the enemy. Yet the sickness contains its own cure. We shall not succeed in saving the planet and its guest, the human species, unless we build «knowledge societies» that prioritize education and research. To address the challenges of sustainable development, we must strengthen our capacity for foresight and prospective analysis. UNESCO’s work of compiling a global knowledge base on the environment and sustainable development goes back several decades, to a time when there was still little awareness of the problem. In 1949, UNESCO launched the first international study on arid zones; in 1970, it created the «Man and the Biosphere» (MAB) program; and its global scientific programs on the oceans and the geosciences are recognized as unique resources. The Intergovernmental Panel on Climate Change (IPCC) has drawn very fully on this database, which must continue to be developed and expanded in the future. More restraint: We need to invent new modes of consumption that are less wasteful and more efficient. For, given the increasing spread of Western modes of development and consumption to the emerging economies of the south, what other choice do we have? Three or four planet Earths would be required if the current consumption patterns of North America were to be extended to the planet as a whole. Less matter: We shall have to «dematerialize» the economy and growth. For it is probably impossible to halt growth. We shall therefore have to reduce the consumption of natural resources and raw materials for each unit of economic production, whether it be energy, metals, minerals, water or wood. This shift of the economy toward the immaterial has already begun with the revolution that replaces atoms by bits, which is central to the rise of the new technologies and knowledge societies. «Dematerialization» of the economy could even favor development in the countries of the south, if the countries of the north were to commit themselves to dematerializing a little more than the countries of the south for a period of about 50 years. But the greatest transformation of our societies will be in the realm of attitudes and behavior. How can we dematerialize production if we remain materialistic? How can we reduce our consumption if the consumer within us devours the citizen? Education for sustainable development will be the key to this change. More concreteness: Concrete and realistic projects, including at the international level, will be needed to bridge the gap between utopia and the tyranny of the short term. Take the case of biodiversity. To safeguard the 34 top-priority ecological zones, which cover only 2.3 percent of the Earth’s land surface but contain 50 percent of the known species of vascular plants and 42 percent of mammals, birds, reptiles and amphibians, the cost is put at some $50 billion, or less than 0.1 percent of global GDP. A natural contract: If we are to cease being the Earth’s parasites, we shall have to sign a new peace treaty with nature. We had the social contract, which binds human beings together, and we must now bind ourselves with nature. The idea will seem strange to some, but it follows on logically from the growth of ecological awareness. If in the future we protect endangered species, if we preserve landscapes in natural parks, we shall gradually be recognizing nature as embodying genuine rights. Foresight will be an absolute precondition of the true democracy of the future. The ethic of the future, which demands that we transmit an inhabitable world to our children, will supply the link between the economy and ecology, between growth and sustainable development. Koichiro Matsuura is director-general of UNESCO.