Time for a rethink on climate change?

28 February 2012

Governments have done so little to reduce greenhouse gas emissions, they should consider investing in the R&D of large scale geo-engineering projects and their governance, according to 26 of the world’s leading environmental economists. Examples could include firing sulphates into the atmosphere, iron fertilisation of the oceans or oceanic ‘heat pipes’. A ten point consensus, published this month in a book edited by two top environmental economists at The University of Manchester, argues that among other things, policy makers should ‘think outside the box’ to tackle climate change.

The consensus further argues that greenhouse emissions should be taxed or capped to help consumers, businesses and governments account for the social cost of their behaviour. Professors Alistair Ulph and Robert Hahn from the University’s Sustainable Consumption Institute (SCI) say that despite ambitious international targets to cut greenhouse gas emissions, little progress has actually been achieved. Their book - Climate Change and Common Sense: essays in honour of Tom Schelling - is published by Oxford University Press and builds upon a University of Manchester conference honouring the Nobel Prize winning economist.

“Emissions from one country may be a small part of the global emissions that drive climate change - which means there is an incentive for such countries not to act to cut emissions unless others do so,” says SCI director, Professor Ulph. “Moreover, the impact of global warming and the costs of reducing emissions vary across regions and time periods, so a divergence of interests pits country against country and generation against generation. More research and development is needed in technologies for removing CO2 from the atmosphere and for managing solar radiation, even though these technologies may not be deployed for decades.”

Game theory reveals a series of virtually intractable problems - such as tipping point analysis and the prisoners’ dilemma - which stand in the way of international agreement between nations. Most game theorists - and Schelling was one - are pessimistic about ever getting agreement on climate change.

Professor Hahn adds: “Many countries already have explicit or implicit prices on greenhouse gas emissions. But the large revenue streams that result should be used productively by reducing other taxes that distort economic activity. If we do fail to regulate greenhouse gas emissions that contribute to global warming or find alternative strategies, then the damage could be catastrophic.”

Meanwhile, a new study led by the Georgia Institute of Technology provides further evidence of a relationship between melting ice in the Arctic regions and widespread outbreaks of cold weather in the Northern Hemisphere. It is believed the study’s findings could be used to improve seasonal forecasting of snow and temperature anomalies across northern continents.

Since the level of Arctic sea ice set a new record low in 2007, significantly above-normal winter snow cover has been seen in large parts of the northern United States, north western and central Europe, and northern and central China. During the winters of 2009-2010 and 2010-2011, the Northern Hemisphere measured its second and third largest snow cover levels on record.

“Our study demonstrates that the decrease in Arctic sea ice area is linked to changes in the winter Northern Hemisphere atmospheric circulation,” says Judith Curry, chair of the School of Earth and Atmospheric Sciences at Georgia Tech. “The circulation changes result in more frequent episodes of atmospheric blocking patterns, which lead to increased cold surges and snow over large parts of the northern continents.”

In this NASA and NSF supported study, published last Monday in the online early edition of the journal, Proceedings of the National Academy of Sciences, scientists from Georgia Tech, the Chinese Academy of Sciences and Columbia University expanded on previous research by combining observational data and model simulations to explore the link between unusually large snowfall amounts in the Northern Hemisphere in recent winters and diminishing Arctic sea ice.

The researchers analysed observational data collected between 1979 and 2010 and found that a decrease in autumn Arctic sea ice of one million square kilometres – about the size of Egypt - corresponded to significantly above-normal winter snow cover in large parts of the northern United States, north western and central Europe, and northern and central China.
The analysis revealed two major factors that could be contributing to the unusually large snowfall in recent winters - changes in atmospheric circulation and changes in atmospheric water vapour content - which are both linked to diminishing Arctic sea ice. Strong warming in the Arctic through the late summer and autumn appears to be enhancing the melting of sea ice.

“We think the recent snowy winters could be caused by the retreating Arctic ice altering atmospheric circulation patterns by weakening westerly winds, increasing the amplitude of the jet stream and increasing the amount of moisture in the atmosphere,” explains Jiping Liu, a senior research scientist in the School of Earth and Atmospheric Sciences at Georgia Tech. “These pattern changes enhance blocking patterns that favour more frequent movement of cold air masses to middle and lower latitudes, leading to increased heavy snowfall in Europe and the Northeast and Midwest regions of the United States.”

Another powerful influence on climate change
The world’s oceans act as a massive conveyor, circulating heat, water and carbon around the planet. This global system plays a key role in climate change, storing and releasing heat throughout the world. To study how this system affects climate, scientists have largely focused on the North Atlantic, a major basin where water sinks, burying carbon and heat deep in the ocean’s interior. But what goes down must come back up, and it’s been a mystery where, and how, deep waters circulate back to the surface.

It is thought that filling in this missing piece of the circulation, and developing theories and models that capture it, may help researchers understand and predict the ocean’s role in climate and climate change. Last week, scientists at Massachusetts Institute of Technology (MIT) reported that they may have identified that “missing piece”, and that it may lie in the Southern Ocean — the vast ribbon of water encircling Antarctica.

The Southern Ocean, according to observations and models, is a site where strong winds blowing along the Antarctic Circumpolar Current dredge waters up from the depths. “There’s a lot of carbon and heat in the interior ocean,” says John Marshall, the Cecil and Ida Green Professor of Oceanography at MIT. “The Southern Ocean is the window by which the interior of the ocean connects to the atmosphere above.”

MIT’s Professor Marshall and Kevin Speer, a professor of physical oceanography at Florida State University, have jointly published a paper in Nature Geoscience in which they review past work, examine the Southern Ocean’s influence on climate and draw up a new schematic for ocean circulation.

For decades, a “conveyor belt” model, developed by paleoclimatologist Wallace Broecker, has served as a simple cartoon of ocean circulation. The diagram depicts warm water moving northward, plunging deep into the North Atlantic; then coursing south as cold water toward Antarctica; then back north again, where waters rise and warm in the North Pacific. However, evidence has shown that waters rise to the surface not so much in the North Pacific, but in the Southern Ocean.

Professor Marshall says winds and eddies along the Southern Ocean drag deep waters — and any buried carbon — to the surface around Antarctica. He and Professor Speer write that the updated diagram “brings the Southern Ocean to the forefront” of the global circulation system, highlighting its role as a powerful climate mediator. Indeed, Marshall and Speer review evidence that the Southern Ocean may have had a part in thawing the planet out of the last Ice Age. While it’s unclear what caused Earth to warm initially, this warming may have driven surface wind patterns towards the pole, pulling up deep water and carbon, which would have been released into the atmosphere, further warming the climate.

In a cooling world, it appears that winds shift slightly closer to the Equator, and are buffeted by the continents. In a warming world, winds shift toward the poles; in the Southern Ocean, unimpeded winds whip up deep waters. The researchers note that two manmade atmospheric trends — ozone depletion and greenhouse gas emissions from fossil fuels — have a large effect on winds over the Southern Ocean.

As the ozone hole recovers, greenhouse gases rise and the planet warms, winds over the Southern Ocean are likely to shift, affecting the delicate balance at play. In the future, if the Southern Ocean experiences stronger winds displaced slightly south of their current position, Antarctica’s ice shelves may be more vulnerable to melting, a phenomenon that may also have contributed to the end of the Ice Age.

“There are huge reservoirs of carbon in the interior of the ocean,” Professor Marshall says. “If the climate changes and makes it easier for that carbon to get into the atmosphere, then there will be an additional warming effect.”

Jorge Sarmiento, a professor of atmospheric and oceanic sciences at Princeton University, says the Southern Ocean has been a difficult area to study. To fully understand the Southern Ocean’s dynamics requires models with high resolution and that’s a significant challenge, given the ocean’s size.

“Because it’s so hard to observe the Southern Ocean, we’re still in the process of learning things,” says Professor Sarmiento, who was not involved with this research. “So I think this is a very nice snapshot of our current understanding, based on models and observations, and it will sort of be a touchstone for future developments in the field.”

Marshall and Speer are now working with a multi-institution team led by MIT’s collaborator, the Woods Hole Oceanographic Institution, to measure how waters upwell in the Southern Ocean. The researchers are studying the flow driven by eddies in the Antarctic Circumpolar Current, and have deployed tracers and deep drifters to measure its effects; temperature, salinity and oxygen content in the water also help tell them how eddies behave, and how quickly or slowly warm water rises to the surface.

“Any perturbation that is made to the atmosphere, whether it’s due to glacial cycles or ozone or greenhouse forcing, can change the balance over the Southern Ocean,” says Professor Marshall. “We have to understand how the Southern Ocean works in the climate system and take that into account.”

Les Hunt
Editor

Reader comments:

From Mr Peter Macdonald:
The Uk represents a little under 1% of the worlds population. If we managed to totally stop producing green house gases we would make very little difference to the overall problem and our sacrifice would be wiped out in a few days by the ever increasing output from Chinese coal fired power stations. Let's stop pretending we are 'green'. We are being overtaxed in the name of carbon footprint reduction and these taxes add significantly to the cost of living especially in the costs of energy. All government efforts are an excuse for taxes that most people think make a difference and therefore are willing to pay without to much protest---it's for the good of the planet after all. RUBBISH. Thse taxes a simply another way to get money out of our pockets and into the exchequer without to much public outcry.

From Mr Stewart Telford:
As a contract engineer that works on many sites, I have not found one engineer that believes in Anthropogenic Global Warming. I suggest to you, as many of your readers are engineers, they will think that your attempt to fight climate change is in King Canute territory (the climate is always changing). Feel free to do a survey and prove me wrong (about what engineers think).

From Mr David James:
Time for a rethink indeed.
As our knowledge to the true nature of both Global cooling and Global
warming gradually improves, our illustrious leaders have thought it is
better to combine these two effects and call them “Climate Change”. At
worst they will be proved right as the climate changes again. There has
never been in “geological” time a static climate.
Anthropogenic global warming may or may not be significant. The climate
will change and change again!
What is beyond doubt is that our pollution and raping of the land and
seas necessary to “feed” our exponential growth in population is now
catastrophic to the old order. Our local illustrious leaders have seen
an opportunity to raise taxes on the back of Co2 in the name of being
green; and whilst there may indeed be a trickle down effect to encourage
better environmental behaviour, we do not stand a hope of forcing “sack
cloth and ashes” onto any of the billions of Asians. They too will also
want to eat well, drive a car and have air conditioning.
The die is cast.
The demand for energy and natural resources will only increase attendant
with further pollution. If we are not part of the problem we will no
longer have any power or ability to do anything about it. For example,
if we eliminated Western consumption today, tomorrow the East would pick
up the slack and we could do nothing about it.
King Canute had the sense to know he could not stem the tide, even
though his courtage thought he should try. It seems to me that nibbling
at the edges of this global crisis will only sate our morality.
I therefore respectfully suggest a radical policy change.
Plan for change………….
You know it makes sense..

From Mr Marcus Gibson:
On the subject of climate change I have to ask whether, following the truly ludicrous prediction of 'Lord' Stern and his Stern 'Report', there is any intellectual reality within the 'environmental economist' community!
It looks as though northern hemisphere surface temps have risen by 0.8'C since 1970, about the same amount by which it fell during 1939-1969! So all the IPCC predictions and climate models have proved to be hopelessly wrong. All those Jerry Springer scientists and environmentalists have yet to admit to it, of course. But the 50 rebels Fellows of the Royal Society pointed this out years ago.

From Mr Rod Dalitz:
Mr Telford notes that engineers of his acquaintance do not believe in anthropogenic climate change. There is little reason to take heed of their opinion, any more than bankers or music teachers. Since the government and universities have put a large amount of effort and computing power into studying the climate, why should anyone not take a lot more notice of their conclusions than the opinions of someone who has never worked in that area?
My own experience of the temperate mountains in America, Europe and New Zealand leaves me in no doubt that the climate is changing rapidly. Since models make it clear that man-made emissions have a large effect on weather and climate, then the only doubt is in the detail.
If you suspected cancer, would you give more weight to a medical doctor or an acquaintance? If you were considering buying shares, would you give more weight to a financial advisor or the man in the pub?
Why is is that so many people distrust scientists?

From Mr Kristen Cadman:
What we really need is a way of motivating some members of society so that we do not need punitive prices for to make people use energy efficiently. There are plenty of ways using existing technology to improve thermal insulation of buildings by an amount which would make a worthwhile difference. Present trends are pretty clearly unsustainable, so why gamble on the accuracy of scientists, engineers or people in the pub? It will be too late if we find out they are right.