Global Warming Is Good

Global warming is good for you

There can be little doubt that global warming is real. When scientists argue about the subject, it is usually in the context of how large a temperature rise they have calculated for the next decade or century, not whether any heating at all will occur. The heat is on, then. At least I hope so: because the greenhouse effect is a good thing.

Consider historical records, and other tracers showing how our climate has varied over the past few millennia. Stepping back just a decade, we find that injections of dust or smoke into the atmosphere, such as from the Mount Pinatubo volcanic eruption and the oil fires after the Gulf war, led to slight coolings (airborne particles reflect sunlight away). Going back to the 17th century, one notes the "Little Ice Age" when the River Thames froze over and frost fairs were held in London on its icy surface. This occurred during an era when there was a dip in sunspot numbers, and so was presumably caused by lessened solar output. Why, we don't know. But it happened.

Starting around AD540, pestilence spread across Europe. This is usually termed the Plague of Justinian (emperor of the eastern Roman Empire), and it was provoked by a climatic downturn. Similarly, several coincidental crashes of disparate, well-separated civilisations are recognised in archaeological records, for example around 1650BC and also 2350BC, with no apparent link other than widespread worsening climate.

So, relatively small perturbations in the amount of sunlight reaching the ground can lead to temperature falls sufficient to provoke the downfall of previously effective agricultural systems and economies.

Looking at the climate over an extended timescale, longer than the Holocene (the relatively warm past 12,000 years), one sees that the usual condition of Earth is far colder than that enjoyed now. The norm is Ice Age. Cool the climate just a little, and a feedback effect drops the temperature further: the Arctic snowfields...