Guardian: Never before in history have human beings been called on to act collectively in defence of the Earth. As a species, we have endured world wars, epidemics, famine, slavery, apartheid and many other hideous consequences of religious, class, race, gender and ideological intolerance. People are extraordinarily resilient. The Earth has proven pretty resilient, too. It's managed to absorb most of what's been thrown at it since the industrial revolution and the invention of the internal combustion engine....