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Tyee's Climate Change Crash Course: Part 7

Why scientists can be certain, while not exact, about climate change and its impacts.

By Eric Nadal, 31 Jan 2013, TheTyee.ca

When it comes to exactly how high the rise will be where, 'uncertainties make precise projections difficult.' But this is certain: sea levels will continue to rise. Watch the video to see attempt to predict U.S. West Coast impacts.

[Editor's note: Welcome to the second to last day of this course. You can find previous installments and catch up by going here. Scientifically trained writer Eric Nadal has created a nine-part series made up of eight short, straightforward, simple to understand classes in climate change, followed by a quiz you will be able to take -- with a certificate to hang on your wall if you pass. Both the last installment and the quiz will be published tomorrow so... start cramming!]

Part 7: 'Uncertainty'

In science, as in life, you should be careful not to overstate what you know, or to pretend to know something you don't, however good your intentions might be. At the same time, you do not need to know everything about a process to know its most important attributes or have enough information to act.

You can know, for example, that a hurricane will hit your town in a few hours, even though you don't know precisely when and where a particular gust of wind will strike or exactly what damage it will cause. And as another writer put it, you can know that a pot of water you have on the hot stove will soon boil, even though you can't predict the location or timing of any particular bubble.

Similarly, when it comes to climate change, we can know what we are doing to the climate's basic drivers, even though we can't predict in certain detail where, when or how we'll feel specific impacts. We know that the CO2 we have put in the atmosphere is trapping a tremendous amount of heat at the planet's surface, providing a massive amount of additional energy for the Earth's chaotic atmosphere and ocean to work with. We know that this extra heat subjects the world to more severe drought, wildfires, floods and extreme storms, placing people directly in harm's way and systematically stressing water and food systems.

We also know from Earth's climate history that, if we wait for the climate to fully respond to our elevated CO2 levels, we could radically alter the planet from the relatively stable climate that civilization has enjoyed for the past 10,000 years. Finally, we know we're imposing this very large change on the planet much faster than it would normally, or perhaps ever, occur in nature, straining the ability of wildlife to adapt and risking a severe dislocation, or even collapse, of entire ecosystems across the globe.

A destabilized biosphere, a dried out planet beset by extreme heat, wildfires, storms, and floods, would be an unprecedented disaster for our world, our civilization, and the children we are bringing into it.

Of course, the effects could be less severe than the world's atmospheric physicists, biologists and agricultural scientists calculate. On the other hand, they also might end up being worse. The possibility of error always accompanies science, but hardly stops us from employing science every second of every day for industry, food, medicine, safety, travel and communications. Are we really to believe that the same knowledge and data that enabled scientists to split the atom, produce the computer, map the human genome, and navigate the solar system, has somehow gotten it wrong about the effects of carbon dioxide in Earth's atmosphere? That seems unlikely.

In fact, some current observations suggest that if science-based forecasts are wrong, their error is in being too conservative rather than too extreme. For example, satellite measurements reported late in 2012 indicate that ocean levels are in fact rising some 60 per cent faster than predicted in the most recent global summary of climate science prepared by the Intergovernmental Panel on Climate Change (IPCC).

And even supposing that impacts which scientists say are likely were, in fact, improbable, would that make it less urgent to halt the build-up of fossil CO2 in the atmosphere? Isn't defending a 10 per cent, or even one per cent, chance of irreversible loss of the climate conditions that nurtured our species a bit like defending a game of Russian roulette on the grounds that you don't know that a bullet will be fired? Or perhaps in the hope that even if one is fired, hospitals and doctors may just be able to save your life and repair the damage? Indeed, it's actually worse than that, because in the case of climate change we're not just talking about a personal decision to play a senseless, deadly game that endangers only yourself, but about decisions that put everyone on Earth into such a game.

About that, there is little to be uncertain at all.

Tomorrow: The final day of The Tyee's Crash Course in Climate Change: How much carbon can we burn without calamity?

Find the entire course to date here.  [Tyee]

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