Climate change is a very real danger, but one that we are already well on the way to fixing. Without wanting to sound complacent, I think it’s a challenge that the current generation will solve. But what then? Do we simply want to avoid affecting the Earth’s climate, like environmentalists say? Or should we aspire to actively manage it?
Ten thousand years ago, before humans started having any significant impact on climate, the ice sheets were retreating across northern Europe and North America at a brisk pace. During the height of the last Ice Age, permanent ice lay 3 kilometers thick across much of the northern hemisphere. This disappeared in a period of a few thousand years, leaving behind features such as Canada’s Great Lakes and Norway’s Fjords. As the ice melted, global temperatures increased by around 8 degrees Celsius, and the sea level rose by an astonishing 120 metres, swallowing huge areas of land, and turning Britain into an island.
By contrast with these enormous changes, human activities are estimated to have increased global temperatures by around 0.5 to 1 degrees Celsius and raised sea levels by 20 cm. Worrying though this may be, it’s a small change compared with natural climate variability in the long term.
So my question is, once we’ve got greenhouse gas emissions under control, are we going to be content to allow Nature to take its course?
Not unless we are happy to see catastrophic changes orders of magnitude greater than anything humans have inadvertently caused. So I think that climate engineering is going to be the next Grand Challenge, perhaps one for the 22nd century.