"Humanity depends on healthy ecosystems: they support or improve our quality of life, and without them, the Earth would be uninhabitable. However, over the past 50 years, fast-growing demands for food, , water and other s have led to an unprecedented degradation of many ecosystem services so that their ability to sustain future generations can no longer be taken for granted. Therefore, reversing ecosystem degradation is one of the great challenges of sustainable development. This is by no means a trivial task as it requires action by all actors in society, including governments, industry and individuals. One of the difficulties is that, even if there was a universal commitment to sustainable development, it is still unclear what goods, services and activities are sustainable and how they could be identified."

"... what you can be sure of is that many organisms have declined to the point where they can never do the services for us we want — even if the service is the pleasure of seeing a rare bird."

"Nature underpins human well-being in critical ways, especially in health. Nature provides of nutritious crops, purification of drinking water, protection from floods, and climate security, among other well-studied health benefits. A crucial, yet challenging, research frontier is clarifying how nature promotes physical activity for its many mental and physical health benefits, particularly in densely populated cities with scarce and dwindling access to nature."