What's The Arctic Death Spiral?

  • The ice in the Arctic is a huge mirror reflecting the sun's heat back into space;
  • Through global warming we've melted this ice and shrunk the mirror;
  • Less sunlight is reflected, causing more warming and further ice-melt, in a vicious circle of positive feedback;
  • Even after we stop CO2 emissions and even if human population reduces, temperatures will continue to rise;
  • The only way to stop irreversible, devastating climate change is to stop releasing CO2 and make the planet colder using geo-engineering;
  • Every day we delay, that colossal task becomes even bigger;
  • We're also melting the ice on Greenland and the Antarctic; unless we stop this, sea levels will rise 70m.
The ice that used to cover the Arctic Ocean is spiralling down towards zero:

Arctic Death Spiral

This chart records volume not area. Measuring just area misses a crucial dimension: the ice is getting progressively thinner, and so melts more quickly each summer.

The downward trend in Arctic sea-ice extent began around 1950. Reliable figures for sea-ice volume start in 1979. It's plotted on rectangular axes below.

What's The Problem?

The IPCC is almost certainly wrong with its claim in October 2018 that
the likelihood of an Arctic Ocean free of sea ice in summer would be once per century with global warming of 1.5C, compared with at least once per decade with 2C
Despite the noise, the best-fit line on this chart of real data looks inexorable and suggests that Septembers with no Arctic sea ice could first appear from 2030 and will become a permanent feature around 2045, with the ice-free periods then extending to last multiple months:

B PIOMAS Ice Volume Apr Sep Current

Remember: the ice is melting because the Earth has got warmer. Even if we stop releasing CO2 into the atmosphere and temperatures stabilise, the ice will continue to melt.

Maybe the IPCC know something the real data doesn't and this line is going to flatten out or curve up before hitting zero. Or maybe the current climate-change models don't work in the Arctic? They don't even match the recorded data for recent years!

Does This Matter?

As Arctic sea ice disappears, the following feedback effects have already started and probably explain why the Arctic is warming at about twice the global average rate:
  • less sunlight is reflected: the Arctic warms faster
  • methane locked in the Arctic seabed and neighbouring tundra for thousands of years is being released: just a small fraction of the estimated deposits would cause 0.5C of extra warming
  • more open ocean means bigger waves, slowing and reducing the formation of the next year's ice
  • the sea channels out of the Arctic spend less of the year blocked by ice, allowing more ice to drift away
  • removing Arctic ice weakens a key driver for ocean currents and slows the rate at which dissolved CO2 is pulled into the deep ocean
Even if we stop further greenhouse gas emissions right now and stabilise atmospheric CO2 at current levels: these feedbacks mean Arctic sea ice will continue to retreat and the global climate will continue to warm.

Our governments and economic modellers base their non-action on misinformation. The world's only Nobel-laureate climate economist, William Nordhaus, states:
There is virtually no chance that the rise in temperature will be less than the target 2°C even with immediate, universal, and ambitious climate change policies.
He suggests we deal with climate change by applying a carbon tax but admits:
If the damage function shows higher costs, or has sharp curvature at or around 2°C ... then the revised optimal policy would have much higher abatement costs
Nordhous's damage function is based on the IPCC's wrong predictions and furthermore does not include the Arctic feedbacks. The real damage function will have both higher costs and sharp curvature.

What Are The Consequences?

The temperature history of the Earth shows our planet has previously had two stable equilibria: an ice-covered ball reflecting most sunlight; and ice-free periods much hotter than today. For the past million years or so we've enjoyed an unstable equilibrium somewhere in the middle, cycling through ice ages and warm periods. It looks like we're about to upset that equilibrium and force the planet into a warm phase never before encountered by our species.

Here is NASA's plot of CO2 levels over the last 400,000 years, showing how we've overshot off the top of the scale:


The consequences of this include:
  • The Greenland ice sheet is 3km thick; it's melting at a rate of 300km3 per year; when it's gone sea levels will rise 7m.
  • The Antarctic ice sheet (the result of 400,000 years of snowfall) is melting at a rate of 80km3 per year; when it's gone... sea levels will rise a further 60m.
  • These melt rates will only get faster, friction with the underlying land will reduce and vast chunks of ice sheet will slide into the sea.
  • Our agriculturally productive land area is going to shrink risking... large-scale starvation.
  • Needless to say this is also terrible news for polar bears.
It doesn't matter whether climate change is man-made or not: unless we act to make the world colder, these things will happen. If we continue with business as usual, they will accelerate.

Note: the Arctic sea ice is floating, so as it melts the sea level doesn't change.

What Should We Do?

  • Why are we still subsidising fossil fuels?!
  • A global carbon tax, which is gradually increased
  • Stop burning fossil fuels asap
  • (Grudgingly) accept that, until we have more renewable energy, we need nuclear power
  • A massive research effort to work out the most cost-effective methods to remove CO2 from the atmosphere
  • Devise and implement global-scale geo-engineering to reduce temperatures eg cloud-seeding, reflect vast amounts of sunlight, plant more trees
The biggest beneficiaries of the greenhouse gases released so far have the greatest moral obligation to act first. Did you know...
When the Industrial Revolution started, the amount of carbon sitting in coal under Britain was roughly the same as the amount sitting in oil under Saudi Arabia.

What Should I Do?

However, individual actions aren't going to help much. We need governments to radically change policy. So please:
If you're concerned about accusations of hypocrisy, don't be: the current system locks us into fossil-fuel use for pretty much all everyday activities.

Any Comments?

Please send any constructive comments to

Credits and References

Author

Ben Horton
Cambridge