Arguments
Over the tipping point
Posted on 6 July 2011 by steve.oconnor
A debate is taking place in a small specialised section of the scientific community that has profound implications for the planet's climate, but you won't hear it mentioned in Parliament any time soon.
The argument is about the Arctic sea-ice and its precipitous decline over the past couple of decades. Those who are up to speed on the issue recognise that the poles are the coalface for climate change, heating up faster than anywhere else on Earth.
Although the polar ice-sheet is thin - in some places less than 1m - it acts like a giant mirror, reflecting the sun and keeping the region cool. Once it’s gone, the dark ocean will heat up faster, accelerating the effects of climate change. If the poles are the coalface, then the Arctic sea-ice is its canary.
Until recently, the conventional wisdom was that once the sea-ice disappears in summer - possibly as early as 2030 - it stays gone, but a study came out recently challenging that view. It concluded that the ice may come and go in somewhat dramatic fits and starts, until it eventually peters out in the second half of this century.
In other words, whichever way you look at it, the canary is dying.
The director of the National Snow and Ice Data Centre, Mark Serreze, and his team have studied the Arctic for over 20 years. He explains: “We’re now committed to an ice-free Arctic in the summer – there’s just too much carbon dioxide in the atmosphere and the planet’s getting too warm. We’ve crossed a tipping point.”
The trouble is, we've really got no idea if (or when) this will automatically trigger other tipping points or feedback mechanisms that could lead to runaway warming. This may take many forms, from shifting ocean currents destabilising vast methane deposits to natural carbon sinks flipping to become sources. Computer models just aren't good enough to tell.
What is known, however, is that natural global warming periods during the Earth's deep past have been severe enough to cause hurricanes with so much force they've left permanent scars on the ocean floor. During these times, the planet shifted to an unstable state where small initial warmings were amplified by only partially-known mechanisms. Some of these episodes were so violent they came close to extinguishing life completely.
We may think we're clever enough to hedge our bets on how much carbon dioxide we can keep pouring into the atmosphere, but just take one look at the recent global financial crisis and ask ourselves, “Are we ready to risk our lives on predictions from a handful of computer simulations?”
Here in Australia, half a world away from the Arctic, the Government will shortly unveil a plan on how we can reduce emissions. It’s a good first step, but it won't be nearly enough by itself.
Beyond Zero Emissions and the University of Melbourne Energy Institute have teamed up to write a courageous plan to transform our energy sector and propel it into the 21st Century.
The plan, which has wind and solar thermal power at its heart, weans us off fossil fuels within just 10 years, with a cost of about $8 a week for households.
Concentrating solar thermal with molten salt storage can yield baseload power even when the sun isn’t shining. Unlike so-called clean coal, which promised much yet delivered little, it is already a proven technology. Unlike nuclear, it doesn't need long-term plans for disposing radioactive waste and decomissioning obsolete plants. Not only will large-scale solar create thousands of jobs, it will revitalise a flagging industrial sector. It may even jolt other countries into action, lest they be left behind.
Building a renewable energy system will require investments in grid upgrades and specific policies to drive deployment such as a national large-scale feed-in tariff. But more than that, it will need courage and leadership from all sides of politics.
As cyclone Yasi and the floods earlier this year have reminded us yet again, the weather is intensifying. Even if we stopped all emissions immediately, the incredible momentum of the climate makes it likely that the worst is still yet to come. Regarding the Arctic tipping point, Serreze adds: "What I find sobering is that the science has moved beyond accepting the inevitability of a seasonally ice-free Arctic Ocean to only questioning the finer points of how we're going to get there."
Even the most hardened skeptic should surely feel a shiver down their spine at the research collaboration underway in the bowels of three British universities. They’re designing a type of pipe, up to 25km in length with one end to be suspended high into the atmosphere using balloons. If taken to production, sulphur aerosols will be injected directly into the stratosphere via these pipes in a desperate attempt to cool the planet. Although vastly cheaper than fixing the real problem, once we start geo-engineering the climate there will be no turning back: we will be condemning future generations to a dystopian nightmare.
Perhaps instead we should take a long, deep breath and think about what’s really important to us. Not just as a society, but as human beings and as part of a wider web of life on this planet. As Beyond Zero Emissions have demonstrated so brilliantly, if we act now - even in the face of huge uncertainty - we could have a chance at turning things around. Then at least we might have one heck of a story to tell our grandchildren.
Now what kind of price would that be worth paying?
(DB) Umm, no, there was not "general agreement"; please re-read the responses and look for mine and Sphaerica's comments (the guest post by Dr Franszen has discussion supporting Dodger's position on oceanic outgassing of CO2).
Edit:
[DB] The post I referenced is the Seawater Equilibria thread. The relevant discussion I alluded to starts at comment 30. Specific relevant comments are numbers 33, 41, 43, 45, 67, 78 and 81.