Sometime this century, after 4 billion years, some of Earth's regulatory systems will pass from control through evolution by natural selection, to control by human intelligence. Will humanity rise to the challenge?

This landmark essay by Tim Flannery is about sustainability, our search for it in the twenty-first century, and the impact it might have on the environmental threats that confront us today. Flannery discusses in detail three potential solutions to the most pressing of the sustainability challenges: climate change. He argues that Australia has a special responsibility when it comes to climate change, and that our prime minister could be a critical player on the global stage in Copenhagen in December 2009 – but only if we take swift and effective action and make sharp cuts in emissions.

Brilliant and terrifying, Now or Never is a call to arms by Australia's leading thinker and writer on the natural world.