February 01, 2011

Article at Cosmos Magazine

OPINION | The Sky Is Not Falling

We are not facing extinction, and climate change is not killing the planet.

By Wilson da Silva

IT’S TIME for a reality check: climate change is not the biggest threat to the planet. It does not threaten all life on Earth. It’s not even the end of humanity.

The United Nations’ Intergovernmental Panel on Climate Change (IPCC), the most authoritative assessment of global scientific opinion, estimates that – if we continue with business as usual – average global temperatures will rise by 1.8°C by 2100 at the low end, and 4.0°C at the high end. Sea levels are estimated to rise an average of 23 cm at the low end of estimates, and 47 cm at the high end.

Yes, these forecasts are fraught with varying levels of certainty and uncertainty, but they are the best estimates from the best minds. And because the IPCC’s reports are produced by consensus, it is more likely that these estimates are conservative rather than exaggerated.

But even the worst-case scenarios are not going to “kill the planet”, as some fringe environmental groups argue. They are not going to endanger all life, nor are they going to see the end of humanity. 

Sir Nicholas Stern, in a British Government report on the economic impact of climate change, estimated that a ‘business-as-usual’ approach would - at worst – lead to a permanent reduction in per capita consumption of up to 20%. That’s going to hurt a lot, but it won’t destroy modern civilisation: global GDP grew by almost 3,700% during the 20th century, and per capita world GDP rose by some 860%.

Yes, it will lead to increased drought, crop failure, disease and extreme weather events. The rise in sea levels is more worrisome: half the world’s population lives near the coast; in some countries (for example, Bangladesh, population 164 million), nearly all the land area is within a few metres of sea level. 

Hence the political, economic and humanitarian consequences may be localised, but nevertheless large- scale and disruptive to global societies: how will rich nations concerned by asylum seekers react when tens of millions of people are displaced and seek a new home?

Even if we do nothing until 2100, long-range modelling suggests the West Antarctic Ice Sheet will collapse and global sea levels rise by at least four metres by the year 3000. The world will be locked into a warming phase from which it will be very hard to turn back.

But we need to distinguish massive disruptions and large-scale loss of biodiversity and human life from societal collapse and even the end of life on the planet. There are very few existential threats to life on Earth: sterilisation of the planet’s surface resulting from a nearby gamma-ray burst, and the ignition of a nearby hypernova, come to mind, and are both extremely unlikely.

Even doomsday scenarios of global nuclear or biological warfare and pandemics will not kill everyone. In fact, it’s hard to think of a plausible collapse in which our species is wiped out or incapable of rebuilding civilisation.

Here at Cosmos, we have argued for science as the basis of rational discussion, and have insisted that critical thinking is a priceless tool we need apply to important public policy and societal decision-making. So while we support the scientific consensus on climate change, we heartily dismiss exaggerated claims of an impending apocalypse. It’s the sort of zealotry that undermines the rational case for taking action against climate change.

Even the destruction wrought by a devastating asteroid collision 65 million years ago did not extinguish life; in fact, it made the rise of mammals – and eventually humans – possible. New evidence suggests that impacts may have been necessary for the formation of life in the first place.

It’s an interesting new take on an old story. It makes me think of Earth as an anvil on which life may have been shaped by what author Arthur C. Clarke once poetically called ‘the hammer of God’.