Earth's nine lives

Like the proverbial cat, the earth has nine planetary life support systems that are vital for human survival, according to Fred Pearce in his article, "Earth's nine lives". He maintains that up to now, the Earth has been very kind to us given that most of our achievements be they farming, industrialisation of cities happened during an unusually benign period when the Earth's regulatory systems kept everything from climate change to the supply of fresh water within narrow comfortable boundaries. But now with the demands, of nearly 7 billion humans, the resources are being stretched to breaking point. Although the effects of climate change are being well documented, to what extent do pollution acidifying oceans, mass extinctions dead zones in these and other environmental problems matter? The author soberly questions how long we can keep stressing these systems without them biting back at some point. This article is available in the New Scientist journal in the HOORC Library.