This article will be split into two parts, this is part 1 of the article. In a previous article we discussed why the climate varies over time, identifying the main change drivers. We discussed how greenhouse gases trapped the Sun’s heat close to the surface of the planet, while the reflectivity of the Earth’s surface (including the effects of pollution and volcanic activity) reflects heat away.
The US Environmental Protection Agency defines climate change as “any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer).” The EPA then defines global warming as “an average increase in the temperature of the atmosphere near the Earth’s surface and in the troposphere…”.
Since the arrival and rapid expansion of complex multicellular life around 530 million years ago (called the Cambrian explosion), and up until the arrival of people on this planet, around 200,000 years ago, the World had faced five mass extinctions. Each extinction event saw and went on to cause gargantuan changes in the planet’s natural order.
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