The climate changers

摘要

The romantic notion that early humans lived in harmony with their environment has taken quite arnbattering lately. Modern humans may have started eliminating other species right from the start: our ancestors stand accused of wiping out megafauna - from giant flightless birds in Australia to mammoths in Asia and the ground sloth of North America - as they spread across the planet.rnEven so, by around 6000 years ago there were only about 12 million people on Earth -less than a quarter of the current population of Great Britain. That's a far cry from today's 6.6 billion, many of us guzzling fossil fuels, churning out greenhouse gases and messing with our planet's climate like there's no tomorrow. So it may seem far-fetched to suggest that humans have been causing global warming ever since our ancestors started burning and cutting forests to make way for fields at least 7000 years ago.