Passing the tipping point 15 September 06

The BBC report mentioned increased wind as being responsible. I wonder if there is any connection between the severe winter in Europe and loss of Arctic ice.

In NZ we have just had a severe winter with one particularly bad snow storm. Normally polar circulates around the Antarctic in a fairly stable fashion, but a severe weather patern sucked a large sample of this polar air over poor New Zealand.

Any comments on this polar air mixing?

There is some evidence that global warming, via changes in the stratosphere, causes huge changes to the Arctic Oscillation and possibly also to its southern equivalent, the Southern Hemisphere Annual Mode. The Arctic Oscillation (which is linked to the North Atlantic Oscillation) has been in a more and more positive state, intensifying westerly winds around the Arctic. Those oscillation changes have caused increased warming in parts of the Arctic and also in Europe, during winter-time.

However, there was no dramatic decline in winter sea ice cover in the Arctic before 2004-05 (declines in summer ice, yes, but always good rebound during winter). The last two winters have seen massive declines of 6% per winter. The Arctic Oscillation was indeed positive for most of the 2004-05 winter, but it actually was negative for most of the last winter. The European winter of 2004-2005 was mainly mild (except for February), the most recent one severe. This would go against your assumption of the present Arctic melting being driven by any sudden change in weather patterns.

It simply seems that the Arctic has been exceptionally warm in the last couple of years, albedo is diminishing and more and more warm southerly winds and currents are pushing up north – just what Mark calls a ‘tipping point’.

Almuth Ernsting

The birds were singing the new green leaves were rustling in a light breeze. The sun warmed my troubled heart.

It was April 18th. I had been working on Earth Day projects to help people understand global warming. I had been writing my reps. I have been indoors, cooped up, worrying about global warming. Then I had to go to the campus. So I got on my bicycle and peddled through this glorious Spring day. And I thought, such a horrible thing as global warming can’t be happening. The world’s telling me everything is fine and wonderful.

That’s the day we reached the tipping point of no return. But no one, not even one scientist, knew.

Will this loss of ice will have major ramifications for the Greenland ice sheet, over and above the continued acceleration of the melting that has been reported recently, if this means that absorption of sunlight at high latitudes is greatly increased. 730 square kilometres of 90% heat absorption as opposed to 730 square kilometres of 10% absorption must ultimately raise the temperature of the air and water circulating the ice sheet?

This has been a topic of interest in the past for me so I guess I will add another factor seldom mentioned on how much heat ice absorbs. It takes as much heat energy to thaw frozen food at 0 C as to heat it from 0C to 80 C once thawed. We all know how a glass of ice water remains cold until the ice melts inside the glass. When we have ice loss, it means much heat was absorbed to melt it. It takes the same heat energy to melt 1 cubic kilometer of ice as it does to raise 80 cubic kilometers of open ocean water 1 C.

What I am sharing is the ice is buffering the warming and, when more of it is gone, there is little left to melt and so this adds to the feedback loop as the waters get a bit warmer and may not cool down enough in winter to freeze again.

I always want to know what we can do to solve a problem and I remain focused on that but I always deal with reality and the Arctic is a serious problem which would be difficult to prevent unless some sort of reflective strategy could be developed to replace the lost albedo buying us enough time to make emission reductions work.

Some sort of reflective mist or an artificial fog so to speak may help like misty buoys anchored at strategic locations. Maybe the buoys could submerge beneath the ice or be relocated in other open water areas during winter. Maybe the buoys could utilize the movement of the current to force water into a hydraulic ramp and then into spray nozzles. Maybe the energy from the waves could be used to power a pump at the buoy location to create the reflective mist.

Many people think we should not use nuclear energy or resort to geo-engineering but what if we have no choice? The longer we delay to develop and implement ideas that can help us, the harder it will be to restore balance. Even if passed a tipping point, we may have a little leverage to get it back on the other side if we acknowledge the need to take immediate action addressing the issue.

It would surely help us to slow the ice loss and stabilize it if possible. The more open waters we have, the more surface area we would have to manage and ideas like I have suggested become more expensive to implement.

Best Wishes, Dan

Dan, one possibility is the Professor Stephen Salter proposal for using vertical axis wind turbines with nozzles to create mists – see here.

I see these as having particular potential if sited to draw fresh water from rivers in Siberia, northern Canada etc and activated during daylight hours (esp. in summer) for maximal dimming effect to counter permafrost thawing, and associated carbon discharges.

Greenland would be good too, but would pose much more practical difficulties to creating non-saline mist and having much impact on the interior.

I’ve written to the fella to ask more about his proposal and its progress, but heard nothing back. In the meantime I seem to have scored 2 top 10 hits for Google query “Stephen Salter climate change” (not that I’m in the business of getting a third!)

best, Jim

Sometimes we have to perform a few experiments and see what happens.

Not only can we gain knowledge of the effectiveness of these ideas but by interacting with nature, we also gain more science knowledge as well.

Best Wishes, Dan

Salter’s proposal seems to hinge on increasing the amount of water vapour in the atmosphere – but since water vapour is a potent greenhouse gas, wouldn’t it be likely to make us even warmer?

A flotilla of Salter’s ships on the east coast of Africa could potentially help green the Sahel – which would be a good thing. However, dust from the Sahel inhibits hurricane formation in the Atlantic, so the USA would probably lose out.

I remain sceptical about “magic bullets” – reducing our GHG emissions still seems to me to be the only possible way forward.

It seems to be that humid climates are overall cooler in summer than drier ones at similar latitude and elevations; at higher latitudes you would expect this even more as the summer nights, when humidity and cloud cover would both warm, are shortest. Most of the mist would remain so because of the hurdle of Latent Heat of Evaporation, though it would tend to linger in the valleys by encumbering and cooling the air.

I’m not a great fan (‘scuse me) of the sea whisks idea since that would surely waft a lot of unwanted salt on to land, unless positioned where trade trade winds blow into the deep Pacific, for example.

Jim

I would have thought that if there was an obvious remedy to Arctic meltdown, some of the best climate scientists would have thought of it. I can’t imagine that somebody like James Hansen would have overlooked it. I think I read a statement by Hansen (sorry, can’t remember where) in which he says that if Greenland was to disintegrate, attempts to halt the melting would probably be tried but almost certainly be futile.

The only geo-engineering proposal which I know got into Science was the stratospheric aerosol one, which has been so heavily criticised by scientist on RealClimate (and George Monbiot wondered in an article whether it could result in even worse droughts in parts of Africa – having read Fred Pearce’s new book, I wonder if it could even switch off the Asia monsoon).

I don’t think any of us here have the expertise to imagine what a climate model run with the kind of geo-engineering discusssed would look like.

More interestingly, though, Hansen recommends a concerted short-term effort to drastically curb methane and soot emissions over the next few years and says that this could reduce the short-term warming of the Arctic and give the urgently needed CO2 cuts a chance to achieve their goal (provided they happen, of course). This makes a lot more sense to me!

Almuth