“We need a new way of thinking, one that tightly links the human-made world of economics and politics with the natural world of climate and biodiversity and with the designed world of 21st century technology. Consider my own home field of study, economics. Sometime in the 19th century, economics largely dropped its traditional attention to land, water and food, as industry replaced agriculture as the leading economic sector. Economists decided, by and large, that they could ignore nature – take it ‘as given’ – and instead focus on market-based finance, saving, and business investment. Mainstream economists derided the claims of ‘limits to growth.'”