June 2010 Archives
When I was doing field work in Arctic Canada, for my master's thesis, we were under orders always to travel from A to B along the coast at 22 metres above sea level, with our eyes on the ground. There was method in this madness.
The orders originated with Wes Blake Jr, a friend of my thesis supervisor. Through us, Wes was hunting for drift pumice. Pumice forms when gas-rich, frothy lava is cooled very rapidly. Because of the gas bubbles, pumice floats. If it gets into the sea, it drifts, for a few years or decades and perhaps a few hundred to a few thousand kilometres, and eventually some of it drifts ashore. Our pumice erupted, possibly from Hekla in Iceland, in about 3,000 BC.
The pumice drifts ashore at sea level. We were following a raised-beach strandline at the elevation at which Wes Blake reckoned the shoreline of 3,000 BC ought to be today. The whole region has rebounded from the weight of the ice that was there up to about 7,000 BC.
Sadly, we never found any drift pumice, but Wes Blake and others did, all around the Canadian Arctic. Its altitude today varies, lower than 10 m in the marginal parts of the archipelago but reaching 25 m and more along a broad axis trending north-eastwards from Bathurst Island to Ellesmere Island. The higher the 5,000-year-old strandline, the thicker the ice used to be. This evidence helped to settle a then-current debate in favour of the idea that the Queen Elizabeth Islands were once covered by an Innuitian Ice Sheet, as opposed to each island having had a smaller ice cap of its own.
Other things wash up on beaches all the time, including whalebone and driftwood that are datable by radiocarbon dating. Sometimes you find datable fossils of shelly organisms that used to live in the beach (or at any rate the nearshore) sediment.
My crowning achievement in this way was to find a bivalve in the "position of death". Its two shells were still joined and the shell aperture was facing upwards. I forget its age, except that it was older than 22 m, but my bivalve was a small contribution to the relative sea-level curve for the locality.
RSL curves tell you lots of things besides the age and altitude of the marine limit (the highest sea level, reached just after the disappearance of the ice) and the history of emergence. With enough curves, you can reconstruct the former dimensions, including the thickness, of the ice sheet. But you are not limited to where the ice used to be. The land around the ice sheet also emerges when the ice load is taken away. During the ice age, it formed a depressed moat around the ice margin. Go somewhat further and you reach the peripheral bulge.
The peripheral bulge is where most of the toothpaste in the Earth's mantle went when it got squeezed away by the growing ice sheet. Upon deglaciation, the toothpaste flows back slowly. All right, I know the analogy is breaking down (ever tried getting the toothpaste back in the tube?), but the peripheral bulge subsides, and here you observe not emergence but submergence of old shorelines.
If you go far enough from the ice sheet, you enter what the geophysicists call the "far field", where relative sea-level change can be complicated, and in any case subtle. But taken together the available RSL curves are an incomparable tool for probing the Earth's inaccessible deep interior. The subtleties in the curves are best explained by variations in the flexural rigidity of the lithosphere and by subtleties in the depth profile of viscosity, or stiffness, in the deeper mantle. Indeed, the information flows both ways (just like the toothpaste).
Another way in which RSL curves help is by showing that toothpaste takes its time. So drift pumice and dead bivalves help us with the complications of interpreting things like the changing gravity field as monitored by the GRACE satellites. Any redistribution of mass, be it due to modern exchanges between glaciers and the ocean or to the slow flow of toothpaste, shows up in the signal from GRACE. Which just goes to show that it's an interconnected world.
In 2006 the Centre for Alternative Technology (CAT) in Wales produced a very radical 'Zero-carbon Britain' scenario, which envisaged UK fossil fuel consumption being cut down to almost zero by 2027, and renewables being powered up to meet almost 100% of UK electricity, with 50% of that from wind, supplying 474 TWh p.a., while overall energy demand was cut by a half. Although welcomed as a visionary exercise setting the outer limits of what might be conceived, as a practical proposal it was met with more or less polite disbelief from most of the energy-policy fraternity.
Four years on, things have changed. The government is now proposing that we get 32% of our electricity from renewables by 2020 – much of it from offshore wind, with up to 40 GW planned. Still a long way short of the CAT's 2006 vision for 2027, but this is now beginning to look more credible. So it will be interesting to see what the reactions are to the CAT's revised 'Zero-carbon Britain' scenario, running now to 2030, which was launched recently.
It is still very radical, but is much more convincing, in part because there is now more solid data to call on, including the UKERC's reports and David MacKay's book, which the CAT relies on heavily.
The new version's basic plan is similar to their earlier one – a massive 55% cut in energy use and massive reliance on renewable electricity, from offshore wind especially, which, as before, supplies much of the transport energy (via overnight battery charging of electric cars) and heating demand (via heat pumps). But the contribution envisaged from wind is now even larger – 690 TWh p.a. mostly from around 195 GW offshore. And also 75.5 TWh from wave and tidal projects, plus 50 TWh (thermal and electricity) from biomass CHP. Some biofuels are used for transport (112.6 TWh), but 65.8 TWh of renewable electricity, plus 99.8 TWh of hydrogen derived from renewable sources, is also used for transport. Demand for domestic heat is met via heat pumps (61.2 TWh of electricity delivering 148.2 TWh) and 24 TWh of solar heat, plus the biomass CHP heat input, along with 104.6 TWh of direct biomass heat – all of course being used in well insulated homes with lower heat needs.
Interestingly, the CAT does not include geological Carbon Capture and Storage (CCS), which it sees as expensive, not very efficient and still in the development stage. Instead it restricts itself to 'the proven technology of land-based Carbon Capture & Storage using natural photosynthesis' and focuses on below-ground storage in soils, above-ground in-situ storage as biomass, and long-life storage in biomass products and in engineered silos. Indeed much of the very interesting section on land use focuses on sequestration, and also on reducing carbon and other emissions from producing (and importing) food – we move away from meat (beef) and dairy (milk). That could be wise, but hard. Possibly even harder, we move away from flying and towards public transport.
On grid balancing, they say that the new offshore wind farms 'will be commissioned at dispersed locations around the country and the back-up generation consisting of biogas, biomass, hydro and imports will help to manage the remaining variability. However, all of this will need to be complemented with a large increase in the management of electricity demand. Both the supply and demand sides of the equation are malleable and both will require intensive management'.
In particular they look to demand side management i.e. rescheduling some loads via smart meters when energy is most abundant, and therefore cheaper, for the consumer. They mention electric storage radiators, heat pumps, electric vehicles, air conditioners, washing machines, fridges, freezers, dish-washers and tumble dryers. Not all on that list will be popular choices!
Another grid balancing option, in addition to pumped storage and gas turbine back-ups, is the supergrid – but while some imports of green power are envisaged from the EU (it seems about 14 TWh p.a), the CAT does not see us importing energy from Concentrated Solar Power projects in North Africa by 2030: it argues that 'security of supply is important, and depending heavily on another region of the world therefore needs to be considered carefully in geopolitical, ethical and financial terms'. And, overall. energy exports (174 TWh p.a) will heavily outweigh imports. In general, reflecting its emphasis on localisation and decentralisation, imports are seen as bad – reducing UK reliance on overseas imports of energy and also food and other consumer items, is seen as a key part in reducing our emissions.
To make it all happen the CAT looks to various changes to the support and pricing system. It backs Feed-In Tariffs, but it says 'to more effectively balance the grid, the government should implement a form of locationally differentiated pricing for new generators within distribution networks to signal the best places to build new capacity, such as at the ends of constrained distribution networks'.
That's debatable – differentiated charging by area will mean high charges for some of the largest renewable generators (e.g. in Scotland). The Scottish government has noted that, under the current system, a power station in central Scotland pays £25 m more for transmission than a similar facility in Yorkshire. The government has said that the current system reflects the cost, and raises revenue for grid improvement. Similarly, the CAT sees it as necessary for an 'interim period, until the transmission network is reinforced'. But basically it sees local micro-grids as a key to a more localised future.
It's certainly an ambitious vision, developing on the new-energy agenda that seems to be emerging in radical ways. And of course with no new nuclear.
What would it cost? The CAT says: 'Offshore wind is a central part, if not the core part, of building a green, sustainable economy in Britain. This transition and development of new industry requires investment. The peak of £30 bn in 2022 represents only 2.2% of the UK's 2008 GDP and delivers an electricity generation system, which has very low fuel costs. If we were instead to generate the proposed output of 599 TWh in 2030 from 50% coal and 50% gas, it would incur a fuel cost of approximately £13.5 bn per annum at 2008 prices. In reality these fuel costs are likely to rise far higher by 2030 and would constitute an enormous unnecessary expense to the general public'. The CAT also notes that, at a price of 4p/kWh, the proposed 159.34 TWh of net exports is worth £6.37 bn and it says that 'this annual income could really help the UK balance of payments'.
The CAT admits: 'The construction of wind turbines at the proposed rate would obviously require a considerable amount of materials.' And, based on 45% being steel and 55% concrete, that is 16.2 million tonnes of steel and 19.8 million tonnes of concrete used over twenty years, 'the embodied energy of steel and concrete for this total build would be 115 TWh'. However, the CAT says that there is a high-energy return on energy invested for wind (it quotes a 28:1 ratio), so the investment is worth it.
You can access the CAT report at www.cat.org.uk.
The grounding line is where, in its forward path, the glacier switches from being grounded to being afloat. Glaciers that reach the sea have to have a calving front somewhere, because the ice can't keep going forever, but there need not be a grounding line.
But suppose there is one. What is the problem? At one level, it is trivial. The glacier remains aground until it satisfies the condition for flotation: there must be just enough water to support the weight of the ice. Multiply ice thickness by ice density (about 900 kg m-3), and water depth by seawater density (about 1028 kg m-3). Unless other forces are at work, the ice ungrounds when the two products are just equal. Seven eighths (900 over 1028) of a column of floating ice is below the water level — which of course explains the phrase "the tip of the iceberg".
Assume that the water depth doesn't change. (It might, but we have enough to worry about without changes of sea level.) The position of the grounding line, then, depends on the thickness of the ice at the grounding line.
If you see something a bit peculiar in that assertion, you are getting a grip on the problem. Next, assume that we know where the grounding line is. What determines the ice thickness there? We can probably ignore the snow that falls on the grounding line itself, so it must be the imbalance, if any, between the delivery of ice from the thicker grounded ice sheet and the discharge of ice into the thinner floating ice shelf.
Suppose less ice arrives than leaves. The ice must get thinner. Now, instead of just meeting the condition for flotation, it more than meets it. So it starts to float. The grounding line retreats. This argument works the other way around: the grounding line advances if more ice arrives than leaves.
This is an excellent example of a nonlinear problem: the position of the grounding line depends on the position of the grounding line. It will stay put only if just as much ice arrives as leaves. That means that we have to consider the forces driving the ice towards the grounding line from the landward side and away from it on the seaward side.
This balance of forces was first stated accurately, but in an order-of-magnitude way, by Johannes Weertman in 1974. His equation has the grounding-line thickness on both sides of the equals sign: on one side, an expression appropriate for grounded ice, where the dominant force is shearing of the basal ice over the bed; and on the other an expression for flow due predominantly to along-flow stretching — acceleration of the now-floating ice towards the calving front.
Weertman graphed these two expressions. The rate of shearing in the grounded ice depends on the surface slope and the rate of change of the ice thickness, which means that it also depends on the slope of the bed. He found that, if the bed slopes upwards towards the grounding line, his two curves either fail to meet — the equation has no right answer at all — or they meet once. If the bed slopes the other way, the curves can meet twice — there can be two right answers.
It is not uncommon for nonlinear problems to have unexpected numbers of right answers. But there is a twist. The answers can be of two kinds, stable and unstable. In the two-right-answer case, the "small" answer is unstable in a reassuring way. If you decrease the snowfall, the ice sheet will go away. Increase the snowfall, and the ice sheet will grow until it reaches the "large" answer, which is stable.
The one-right-answer case is unstable. Knock it off its perch, for example by reducing the supply of snow below that with which it was in equilibrium, and the equation pushes the grounding line forward until it reaches the edge of the continental shelf, while if you increase the snowfall the equation makes the ice sheet dwindle and disappear.
It takes some getting used to, but all the evidence and analysis now point to the one-right-answer case being the "right" right answer. It seems that the West Antarctic Ice Sheet — an ice body grounded below sea level with its bed sloping upwards down-flow — can coexist peacefully with the rest of an unchanging universe only if its margin is at the edge of the continental shelf — or nowhere.
A YouGov poll for EDF Energy in May found that 64% of over 4000 people asked across the UK now say nuclear is needed as part of a balanced energy mix for the UK, compared to 65% last year, 62% in 2008 and 59% in 2007. The regional picture varies: 69% of people in the East of England felt nuclear was needed as part of a balanced mix. In the South West 65% agreed. But it fell to 61% in Scotland.
Interestingly, among Lib Dem supporters, 58% nationally agreed that 'nuclear energy has disadvantages, but the country needs it to be part of the energy balance,' with 47% backing (32% opposing) new nuclear. 63% of Tory and 50% of Labour voters also backed new nuclear.
However, you have to careful with statistics: net support (% for, less % against) nationally was only16% for nuclear, though it was an increase on the 14% recorded in 2009. It is also instructive to look at support for other options: net support for renewables was 61%, although that had decreased slightly from the 64% in 2009 The levels of support also depend on what question you ask: a YouGov poll of over 2000 people for Greenpeace, in late April/early May found that only 34% felt that the government should increase the amount of public money it spends on nuclear power, while the figure rose to 58% for wind power.
This seems to reflect the national view – nuclear may have to be accepted, but renewables are more popular. For example, in the YouGov poll for EDF, in Scotland , which is aiming to get 50% of its electricity from renewables by 2020, only 47% of Scots supported replacing existing nuclear plants when they closed, while, 80% backed offshore wind farms and 69% were in favour of onshore turbines. 74% of Scots said their impression of wind farms was favourable, compared to 43% for nuclear.
Cost was a key issue for many people in the YouGov poll for Greenpeace – 41% felt that nuclear power was expensive, and had never been built on time and will end up requiring taxpayers' money, while 23% disagreed, and there were 36% who didn't know. An even more crucial issue for many people is the absence so far of an agreed solution on waste 65% felt that an agreed solution on waste was necessary before new power stations were built. Only 23% didn't mind and 12% didn't know.
This continued concern is perhaps surprising given that the industry keeps saying that the proposed new reactors will produce less waste. However the reliability of this message has been challenged. The spent fuel from the proposed new reactors is not going to be reprocessed. That means it will contain all the plutonium and other isotopes created in the fission process. So in effect there will be more high-level waste than at present – when the plutonium extracted. And the aim is to keep the spent fuel stored at reactor sites for up to 150 years. Moreover the plan seems to be to try to improve the economics of the reactors, by using more highly enriched fuel and to go for high fuel burn-up, with longer residence times in the reactor. The resultant spent fuel will therefore be around 50% more radioactive. Not something you'd like on your doorstep, as local anti-nuclear groups have made clear. The earliest date for the creation of a final home for high-level waste, assuming a community can be found that is willing to take it (with suitable cash inducements), is 2040.
Abandoning reprocessing does mean that there will be less intermediate and low-level waste from the new reactors, but then we are not short of that, from the existing reactor fleet – and from the ongoing process of decommissioning. This is already creating problems. The low-level nuclear waste 'repository' at Drigg is almost full, with their being no room from, for example, for wastes from the old Chapel Cross Magnox complex in Scotland, which is being decommissioned. The plan is it seems to dump the resultant contaminated soil and rubble in Cumbria, with 12 lorries a day destined for the former open-cast coal mine at Keekle Head, near to the source of the river Keekle. However, it's been claimed by local opponents that he radioactive wastes could leach into the land. Similar moves to try to dump low level wastes around the country (e.g. in land-fill sites) have been opposed by local groups.
For more information, visit Radiation Free Lakeland.
Opposition to nuclear in the UK has not reached anything like the levels seen in Germany, where more than 140,000 people took to the streets in April to commemorate the catastrophe of Chernobyl, and demand an immediate end to nuclear power. 120,000 people formed a 75-mile human chain that stretched from the nuclear power plant in Kruemmel through the city of Hamburg along the Elbe River to the nuclear plant in Brunsbuettel, on the North Sea coast. Meanwhile, in southern Germany, 17,000–20,000 people surrounded the reactor of Biblis and in Ahaus 7,000 protested at the interim radioactive waste storage facility. The scale of the protest were seen as indicating significant opposition to Chancellor Angela Merkel's proposal to revoke a law that would shut down nuclear plants by 2020 – the numbers exceeded all expectations, on scale comparable to the mass anti-nuclear movements of the 1970s/1980s.
Back in the UK, local groups and national campaign organisations like Friends of the Earth and Greenpeace apart, the main signs of opposition have come form the Lib Dems, the Green Party and the SNP. And with an anti-nuclear Lib Dem as Secretary of State for Energy and Climate Change, the issue has moved up the political agenda.
Overall there is clearly still a sizeable minority in the UK and elsewhere who are concerned about the nuclear option. A Eurobarometer survey of 26,470 EU citizens across all EU states, carried out in September and October 2009. It focused on safety issues and found that while 59% of those surveyed felt that nuclear plants can be operated safely, most believed that the risks related to nuclear energy are underestimated, with a lack of security against terrorist attacks on power plants and the disposal and management of radioactive waste identified as the major dangers. So 82% agreed that it would be useful for nuclear waste management to be regulated at the European level. But while in a 2006 poll, 62% thought that nuclear could help combat climate change, only 46% now did. That's a significant change, in that concerns about climate change are one of the main drivers of support for nuclear. Even so, overall 17% of those asked felt that nuclear's share of electricity generation should be increased (up from 14% in a similar poll in 2006), while 39% (up from 34%) felt its share should be maintained. But 34% felt its share should be reduced (down from 39% in 2006).
Commenting on the survey, the European nuclear industry trade association Foratom, said: 'Experience shows that the more citizens know about nuclear energy, the more they are in favour of it.' That's not immediately obvious. As in Germany and elsewhere, in the UK a lot of the opposition has been led by local groups near the planned plants at existing sites, like SHE at Hinkley, and BANNG at Bradwell. CANE at Sizewell, who are more than familiar with what nuclear power has to offer. It will be interesting to see if their disaffection spreads.
A wide range of local and national groups are campaigning on specific issue and against nuclear in general:
For pro-nuclear lobby views, visit:
In a newly-published paper, Matthias Huss and colleagues squeeze a bit more information out of the well-studied records of mass balance from the Swiss Alps. We know more about alpine glaciers than those of any other region, except perhaps Scandinavia, so it is surprising and interesting to learn that there is yet more to be said.
Huss and his co-authors compile a surprising amount of quantitative information. As well as conventional mass-balance measurements made over the past 60-odd years, they have found scattered records, and made geodetic measurements of surface elevation changes from maps, back to 1910, and have also brought measurements of meltwater discharge to bear on the problem.
They do an impressive job of tying these diverse kinds of information together with a model of glacier responses to climatic forcing. They simulate the climate, day by day, with precipitation and temperature data from weather stations extrapolated to the elevations at which the glacier ice is found. Their model of the response to temperature, for example, is a so-called temperature-index model. There is abundant evidence that, when it gets hotter, the glaciers yield more meltwater, and we can use temperature to predict meltwater in a reproducible way.
Their main contribution, however, is the light thrown on the evolution of glacier mass balance in the Alps over recent, and maybe near-future, decades. The authors show that there is a clear signal of the Atlantic Multidecadal Oscillation embedded in the 20th-century history of alpine mass balance.
I have trouble keeping up with the acronyms in this field. ENSO (El Niño-Southern Oscillation) and NAO (North Atlantic Oscillation) are easy because they have become familiar, but the AMO was new to me. This oscillation of sea surface temperature in the North Atlantic has a period, or quasi-period, of 60-70 years, and like all of the others (except perhaps for ENSO) it is an empirical fact rather than an understood physical phenomenon. That is, we can see it in the climatic records, but we have no explanation of why it is there. Is it real? Good question.
I don't think there is any question, though, that we can now see the AMO in the response of the glaciers of the Swiss Alps. As the authors point out, this signal may have predictive value. Large as the year-to-year variability is, we know that the glaciers of the Alps have been suffering particularly badly in recent years. The link to the AMO suggests that things may not be quite so bad in the next couple of decades. Of course we have to assume that the AMO is a phenomenon that is "real" enough that it will evolve as its past course suggests, but the fact is that we don't know enough about it yet.
On the other hand, there are some ideas out there. The A for "Atlantic" might be an important clue, for example, suggesting a link with the oceanic meridional overturning circulation, in which the shallow northward flow in the North Atlantic sinks at high latitude and returns southward at depth — taking dissolved atmospheric gases with it.
Wang and Dong offer an intriguing new twist on this angle. They show that the AMO pattern can be seen in the atmospheric concentration of carbon dioxide, measured at Hawaii and the South Pole since 1958. You have to subtract both a noticeable seasonal cycle (the vegetated landmasses take up CO2 in northern summer and release it in northern winter) and a long-term trend (the more affluent and numerous we get, the more gas we emit). What remains is a definite low in CO2, reaching about 2 parts per million below the 1958-2008 average, between the late 1960s and the mid-1990s. This matches in time persuasively with a cool phase of the AMO.
We are still far from a physical explanation of why the North Atlantic climate oscillates. Nobody knows why the oscillation takes about 60-70 years. We can't even be sure which way the arrow of causality is pointing. Is the CO2 low because the ocean surface is cooler and better able to take it up? Or is the ocean cooler because there is less CO2? In fact, the arrow of causality could well be chasing its own tail. But these links between ocean temperature, greenhouse gas and the behaviour of glaciers are worth exploring because of the prospect that we might be able to turn guesswork about the future into predictability.
The latest Water Commission rulings have now come out on how to distribute water resources on the island of Maui, Hawaii. These rulings discuss how to distribute water from diversion ditches owned and operated by the last sugar-cane plantation of Hawaii Commercial and Sugar (HC&S) who is by far the largest water user on the island. The historical and future contexts of Maui are important in understanding why commercial and native Hawaiian interests have a very difficult time becoming aligned in any significant way.
In the late 1800s and early 1900s settlers to Hawaii established large plantations that over time grew sugar cane, pineapples and other crops. The best land for growing these crops generally lies on the leeward side of the islands that are relatively dry, sometimes almost desert-like. As a result of prevailing Northeasterly winds, the water is precipitated out of the Pacific clouds on the eastern sides of the islands before reaching the western portions of the islands. In order to provide the water required for large agricultural plantations, a series of diversions ditches over 100 miles long along takes water from the windward side of East Maui around to the central valley for the sugar-cane plantation.
However, over the last few decades, the plantations on all Hawaiian islands have been shutting down due to having difficulty competing economically on the global market. The HC&S plantation is the last of a dying breed in Hawaii, and many environmental and pro-native groups wouldn't be surprised if the plantation shut down tomorrow – and for the most part they'd prefer that ending. As plantations on the islands have shut down the question arises as to how to allocate the water that previously diverted for agriculture. The case of reallocating some water from the previously fully diverted Waiahole Stream on Oahu has potentially set a precedent for using water for the purposes of native rights and environmental services. The native rights are primarily concerned with growing taro. Because taro is normally grown in flooded fields and patches that reside adjacent to streams and divert water into the fields before returning most of the water. Some species of taro can be grown without flooded fields, but those varieties are less common.
However influential the ruling for the partial reallocation of diverted water in the Waiahole case, it concerned water becoming available from the closing of a sugar plantation, Oahu Sugar. The water essentially became up for grabs. The cases on Maui for the Ne Wai Eha (West Maui) and East Maui concern a sugar plantation that is still operating. Furthermore, the push for renewable fuels in the US have led to federal grants going to investigate the use of Maui lands for biofuel development. This added pressure from the federal government may overcome any economic and legal pressures to either shut down HC&S the sugar plantation or divert more water to other uses on the island. Other pushes for general energy independence, an abundance of sun and water (when considering the entire island of Maui) generally make Maui as attractive as any location in the US states.
Whatever happens, the allocations of water and land use on Maui are a microcosm of the pressures of industrialized countries trying to make money and renewable energy using large plantations/farms and higher wages than countries like Brazil that also have the requisite natural resources, but currently not the same wage and environmental management pressures.
As the most dynamic world region, China is poised to become fully established as a global powerhouse. Challenges, however, are abundant, and macroeconomic policies need careful balancing to sustain "growth" while avoiding overheating, and keeping social and environmental frustrations from boiling over. The Chinese national government now considers introducing a real estate tax (Financial Times, June 11, 2010). Such a tax is motivated by a number of reasons:
- The Chinese real estate market is overheated, and property speculation may feed an unpleasant bubble.
- Being object to speculation, many flats remain empty (speculators simply wait for the right moment to sell again). A tax would provide incentive to utilize flats.
- Local government are heavily indebted by recent infrastructure investments. Currently they rely on new land development (appropriation and re-sale). A tax would provide a stable source of income.
The effects of a real estate tax are difficult to predict and also depend on other market forces and developments. For example, there is fear that if not well-handled, the property market could crash. Nonetheless, it is educational to also understand possible profound consequences of a real estate tax on other domains.
A reduction of the rate of land appropriation directly benefits farmers who are not going to be expelled anymore. Furthermore, profit margins of speculators would be reduced. Money would be available locally to provide service also for migrant workers, up-to-now treated as "second-class citizens".
Environment and GHG emissions:
The recent surge in GHG emissions was to significants parts driven by capital investments, such as land development and infrastructure building (Peters et al., 2010, and citations therein). A reduced rate in new constructions induced by a real estate tax would dampen GHG emission growth.
Recent development was, as indicated above, mostly motivated by the need of local governments to raise income, resulting in uncontrolled semi-dense sprawl - in many cases without public transit access. This lack of proper land-use is one of the main factors driving unsustainable urban transport (Creutzig et al., 2010). A real estate tax could, if well implemented, decelerate urban sprawl and provide funding for public transport and non-motorized transport infrastructure.
Finally, a quick reference to economic theory reveals the full scope of this instrument. The Henry-George Theorem claims that in a spatial economy public goods are optimally financed by land rents that decline with distance. One of the most impressive examples of its application is the Hong Kong MRT which finances public transport by highrise development on top of its station (and high quality pedestrian accessibility boosting ridership). As a rapidly developing and urbanizing world region, the application of the Henry-George Theorem seems to be ideally suited for China: Develop public transit and land simultaneously to reap the positive externalities of public transit provision.
Financial Times, June 11, 2010. Property tax offers to pave way to China's social reform, by Geoff Dyer
F. Creutzig, A. Thomas, D. M. Kammen, E. Deakin (2010) Transport Demand Management in Beijing, China: Progress and Challenges. In Low Carbon Transport in Asia: Capturing Climate and Development Co-benefits, edited by E. Zusman, A. Srinivasan, and S. Dhakal (Earthscan, London, 2010) ISBN 9781844079148
G. Peters, D. Guan, K. Hubacek, J. C. Minx, C. L. Weber (2010) Effect's of China's Economic Growth. Science 328:824-25
**Not Wales, or Scotland…they want renewables**
The Welsh Assembly Government's new Energy Policy Statement 'A Low Carbon Revolution', sets out an approach to accelerating the transition to a low carbon energy economy in Wales, focusing on efficiency measures and the use of indigenous renewable forms of energy such as marine, wind, solar and biomass. It claims that by 2025 around 40% of electricity in Wales could come from marine sources and a third from wind.
In addition to local community-level micro-generation projects, it proposes the use of offshore wind around the coast of Wales in order to deliver a 15 kWh/d/p (per day per person) of capacity by 2015/16 and to capture at least 10% (8 kWh/d/p) of the potential tidal stream and wave energy off the Welsh coastline by 2025, and it wants onshore wind to deliver 4.5 kWh/d/p of installed onshore wind generation capacity by 2015/2017. It will back small-scale hydro and geothermal schemes, where they are environmentally acceptable, in order to generate at least 1 kWh/d/p, and wants bioenergy/waste to deliver up to 6 kWh/d/p of electricity by 2020 – 50% indigenous/50% imported – also offering an additional heat potential of 2–2.5 kWh/d/p.
It says that 'any new fossil fuel plants should be carbon capture ready with fully developed plans for carbon capture and storage; and that these plants maximise efficiency through use of waste heat and co-firing where appropriate' but adds 'we remain of the view that the high level of interest in exploiting the huge potential for renewable energy reduces the need for other, more hazardous, forms of low-carbon energy and obviates the need for new nuclear power stations'.
That puts Wales in the almost the same situation as Scotland. Although its renewable resource may not be as large as that in Scotland, Wales sees no need to develop new nuclear plants.
Scotland of course has been making that case for some while, with the ruling Scottish National Party being implacable opposed to new nuclear, much to the annoyance of the Westminster government. Equally resolutely, the Scottish government has backed renewables. As a result, Scotland now generates around 30% of its electricity demand from renewables, with the contribution from on-land wind (with over 2GW of capacity in place) having overtaken that from hydro, and by 2020 the intention is to reach at least 50%, with wave and tidal power making major contributions.
Scotland's marine renewable resource is certainly very large, SNP leader Alex Salmond described Pentland firth as making Scotland 'the Saudi Arabia of marine energy'. 1.2GW of wave and tidal current projects has now got the go ahead in Pentland Firth and Orkney waters and the potential has been put at up to 20GW or more.
The Scottish government has been pushing ahead, most recently via a new £12m Wave and Tidal Energy: Research, Development and Demonstration Support fund – to be known as WATERS – to support the testing of new wave and tidal prototypes in the seas around Scotland. It also has a revenue support system offering five Renewables Obligation Certificates (ROCs) for every MWh of power produced and tidal systems and three ROCs per MWh for wave systems – well in excess of the UK national support system, which only offers 2ROCs/MWh for wave and tidal current projects. In addition, the £10m Saltire Prize, funded by the Scottish government, aims to accelerate the development of commercially viable marine energy. The winning entry, to be chosen in 2017, will be required to harness tides or waves to generate 100MW of electricity over a two-year trial undertaken at some point between 2012 and 2017.
However, Cabinet Secretary for Finance and Sustainable Growth John Swinney has noted that electricity from wind and marine energy was not the only option. Scotland's new Renewable Action Plan also focuses on renewable heat and he says: 'Heat from renewables needs to rise tenfold in the next decade and we will investigate all options to boost the sector, from large scale industrial plants, more energy from biomass and waste, through to microgeneration. We will support growth in, and diversification into, the renewable heat sector with further targeted inward investment.'
The plan outlines a range of ideas consistent with the targets to achieve 50% of electricity and 11% of heat from renewable sources by 2020.
Meanwhile Scotland is sticking to its anti-nuclear position. A 126-page report 'Determining and Delivering on Scotland's Energy Future', from the Scottish Parliament's Economy, Energy and Tourism Committee, say: "Scotland does not need a new generation of nuclear power stations to be constructed". Instead, the committee calls for "markedly" increased investments in energy efficiency, renewable energy, cleaner fossil fired thermal plants, and if necessary, the construction of a new generation of larger fossil-plants with future carbon capture.
Nevertheless, in a slight concession, it adds that, since most of its existing coal plants and its two old nuclear stations, Hunterston B, and Torness, are scheduled to close and it will take time for the renewables to catch up, 'there will be a need to extend the operating lifetimes of the current generation of nuclear power stations in Scotland to allow time for the transition to a new electricity system'.
That of course has to be put in context. As SNP MSP Dave Thompson told Newsnight Scotland, 'At the moment we export 20% of the electricity we produce, which is roughly equivalent to the electricity produced by nuclear in Scotland. If nuclear closed down tomorrow, we would still be producing enough electricity to keep us going in Scotland. What we have to look to is the future, where as we develop renewables: we're going to be producing potentially ten times the amount of electricity we actually need in Scotland, so we're going to be exporting massive amounts of electricity to other countries. There's no point in bringing on new nuclear power stations. We just don't need them (and) the Scottish public don't want them.'
The latter assertion may be stretching the point a little. A survey in 2009 of 3,000 people in Scotland, conducted by the Holyrood administration, found that 53% of thought that nuclear energy will be needed in the future to help ensure a secure energy supply, although more people said they preferred renewables to nuclear by a margin of two to one.
As I will be exploring in my next blog entry, subsequently the pro-nuclear position may have strengthened, in Scotland and elsewhere, but the renewables are still supported much more strongly and the Scottish government, like the Welsh Assembly government, has clearly focussed on that.
And there the matter rest for now. None of the proposed 10 new UK nuclear sites are in Scotland or in N.Ireland. One though is in Wales, at Wylfa. Whether that will survive Welsh opposition remains to be seen. It could well be that they will all be in England with, under coalition agreement rules, the strongly anti-nuclear Lib Dems now being unable to vote in opposition, leaving just the Green Party to fight that corner.
It's clear that Antarctica's Wilkins Ice Shelf has suffered considerable disintegration, breaking up in 1998, 2008 and 2009. What's been less clear is exactly where all of the heat to cause the collapses came from. Now elephant seals carrying sensors on their heads have helped solve the mystery.
The sensors revealed the seals were diving to greater depths than current bathymetry records acknowledged existed, Daniel Costa of the University of California explained at the International Polar Year Oslo Science Conference. This indicated the presence of troughs in the continental shelf underneath the ice; it seems these troughs enabled warm circumpolar deep water to travel onto the continental shelf and help weaken the ice above. A paper on these results is currently under review at GRL.
Not only have the seals helped oceanographers and glaciologists but the data they have collected could help predict their own future as climate changes in the Antarctic Peninsula. Information gathered during an IPY project shows that elephant seals tend to forage in circumpolar deep water. Crabeater seals, on the other hand, feed in both circumpolar deep water and Antarctic surface water, and stray much less far from the ice shelf around the peninsula.
If winds speed up in the future as climate change predicts they will, this is likely to cause more circumpolar deep water to intrude onto the continental shelf, bringing additional heat to the region. While probably a bonus for the elephant seals that forage for fish and squid in such water, it's likely to reduce the amount of sea ice off the Antarctic Peninsula. That could be bad news for crabeater seals as they feed on krill, which like to live under pack ice. Crabeater seals also rely on sea ice to breed, unlike land-breeding elephant seals. So it looks like elephant seals could become more abundant in the Antarctic Peninsula and crabeater seals less so.
That said, the past has also seen changes in the distribution of wildlife in the Antarctic region, Costa explained. Analysis of seal fur from old haul-out sites in the Ross Sea region has shown that elephant seals used to visit the region but they no longer do.
Frost flowers, the delicate structures that form on the surface of fresh sea ice, have been implicated in mercury depletion events – the drop in atmospheric mercury levels at the poles in springtime. Now researchers have come up with a potential mechanism for how the flowers take up mercury.
Speaking at the IPY Oslo Science Conference, Jody Deming of the University of Washington, US, explained how she and her colleagues discovered microbes living in the frost flowers, the first indication that the structures can support organisms. It's protective exopolymers secreted by these bacteria that absorb the mercury.
Deming doesn't think that anyone had looked for microbiology inside frost flowers before because of their extreme conditions – low temperatures (frost flowers form at temperatures of less than –8 °C), high salinity due to the expulsion of brine as the sea ice freezes below, high ultraviolet levels, and a brief lifetime before being dispersed by wind or squashed beneath snow.
As part of Canada's Circumpolar Flaw Lead project, the team found lots of frost flowers, with dendrites 3–5 cm long, on thin ice in December 2007 and January 2008. Epifluorescence spectroscopy revealed the presence of microbes. What's more, when the team grew frost flowers in the laboratory it found that the saltier the frost flower, the more bacteria it contained. It seems that bacteria are forced out of sea ice as it freezes, alongside salt. "Bacteria are impurities just like brine is," said Deming.
Exopolymer concentrations in the frost flowers were 26 times higher than in sea ice. These gelatinous substances are secreted by microbes to help protect them from dessication, freezing and heavy metals. The polymer binds to the metal; it's this action that the researchers believe is causing frost flowers to adsorb mercury during depletion events.
A paper on the work is in press at Geophysical Research Letters.
Castration might sound like a controversial solution to the human population growth that is boosting carbon emissions, but the operation in question is for reindeer, not people. Rising winter temperatures can cause freeze-thaw cycles that create thick ice layers on top of snow; this makes it harder for reindeer to reach the lichen that they feed on beneath.
So how can castration help? Unlike normal males, castrated males retain their antlers during the winter, enabling them to dig grazing holes through snow and ice, explained Eli Risten Nergård of Sami University College and the Norwegian School of Veterinary Science at the IPY Oslo Science Conference. Although females also retain their antlers they may not be strong enough to dig effectively; both females and young reindeer can exploit the holes made by castrated males.
But animals castrated using the modern tong method have weaker antlers and less muscle bulk than those treated with the traditional biting technique used by the Sami people of Northern Scandinavia. Nergård has found that the tong technique cuts the reindeers' testosterone levels to zero whereas the traditional technique, which is no longer permitted under Norwegian animal welfare legislation, leaves the animals with a reduced level of testosterone. So reindeer castrated in the traditional "gaskin" way are likely to be better able to clear ice and snow with their antlers over the winter than other castrated males. Castrated males also have an increased chance of survival over entire males because they don't lose weight and body condition during the rutting season.
Nergård, who has been working as part of the EALAT study, says preliminary results indicate that it may also be possible to castrate the reindeer using a vaccine.
International Polar Year science conference kicks off in Oslo
It seems that the organizers of the International Polar Year Oslo Science Conference were inspired by the city's hosting of the Eurovision Song Contest just a couple of weeks ago. Delegates at the opening ceremony this morning were greeted by Norwegian teens dressed in snowsuits singing, playing the drums and issuing apparent cries for help through a frozen trumpet as the first number ended with the sound of melting water and cracking ice. Interspersed between the musical entertainment, which included Norwegian Eurovision host Haddy N'jie and culminated with a rendition of Michael Jackson's Heal The World, were more serious messages about International Polar Year. This vast international collaboration brought more than 50,000 scientists from 60 countries together to work on 160 projects over the course of 30 months; more than 2000 researchers are now in Oslo to share their findings in the largest-ever gathering of the polar-science community.
Russian scientist Artur Chilingarov, who planted a Russian flag beneath the North Pole in 2007, announced at the ceremony that he is lobbying for an International Polar Decade to start in 2011. David Carlson, director of the International Polar Year International Programme Office, told environmentalresearchweb that he believes this move is a compliment to International Polar Year and indicates that scientists think it's worked well. He is less keen on the concept of a decade, however, as it is both too long and too short a time period. International Polar Year was sold to funding bodies as an intense 30-month research push, so in this sense 10 years is overly long but polar research will be vital over more than the next decade. Indeed, there is still much analysis to carry out from the data collected during International Polar Year.
We all know something about icebergs, even if only that one of them sank the Titanic. Working back from what you know about that, you will probably recall that icebergs come from glaciers that reach the sea, and that they are produced in calving events. But that is as far as most people's knowledge goes.
It may come as a surprise that until recently glaciologists didn't know much more than this either. Even now we cannot predict the rate of production, still less single calvings. But our ideas have taken some steps forward lately.
The calving rate is the velocity at which bits drop off the glacier at the calving front. One complication is that the calving front need not be immobile. The calving rate is actually the rate at which ice arrives at the front — the ice velocity — minus the rate at which the front advances or retreats — the rate at which the glacier's length changes.
Why doesn't the ice just keep going? One answer, only partial, is that sometimes it does. Instead of a calving front we have a grounding line. But this is turning one question into two (or more).
The first question, Why do some glaciers end in floating tongues?, is rather easy to answer, although much harder to model. The glacier stays in contact with the solid bed until it satisfies the condition for flotation, which is that there must be just enough water to support the weight of the ice.
The second question, What makes the iceberg finally decide to calve?, has been harder to answer. Early observers noted an apparent relationship between calving rate and water depth: the deeper the water, the faster the rate. But this fails to account for variations of the calving rate with time. Kees van der Veen found that during its rapid retreat the calving front of Columbia Glacier was where the glacier was 50 metres thicker than required for flotation. This was an advance, but still did not relate the calving rate to what we know about glacier dynamics. The same can be said of the argument of Andreas Vieli and co-authors that the glacier-specific 50 m should be replaced by some constant fraction of the water depth.
That missing link between observed behaviour and understanding of dynamics may finally have been forged by Doug Benn, Nick Hulton and Ruth Mottram. They argue that calving happens when a transverse (across-flow) surface crevasse deepens to a state in which its base reaches water level. It is a very fruitful idea.
The tip of the crevasse is at that depth at which the weight of overlying ice is just able to keep the crevasse walls together against the longitudinal tensile stress that is pulling them apart. So there is our link to dynamics, because the longitudinal stress is just the rate at which the ice is accelerating towards the terminus, and is something we can have a shot at predicting.
But there is more. A crevasse that propagates down as far as water level is likely to fill with water, the weight of which will help to resist closure and make it much more likely that the crevasse will propagate all the way to the bottom of the glacier, or in other words to produce an iceberg.
There may be yet more. No ice shelves are known to exist where the mean annual temperature is warmer than about —5°C. Perhaps that is because ice colder than that keeps going when it reaches the sea, and perhaps in turn that is because its crevasses fail to make contact with water when they propagate downwards. But that is an idea awaiting exploration.
The Benn work is certainly not the last word on this subject. For example in the latest issue of Journal of Glaciology Jaime Otero and co-authors make the new idea more numerically versatile by improving the calculation of the crevasse depth and of the stress field. Relying on measured ice velocities, they reproduce numerically the stable position of the calving front of a small tidewater glacier in the South Shetlands.
We still can't stop icebergs hitting ocean liners, but there are plenty of other reasons for wanting to understand calving rates, and the dynamicists are starting to make progress.
The UK offshore wind, wave and tidal power resource could supply about six times current levels of electricity demand, and even if we only exploited part of it, the UK could become a net exporter of power, according to the first comprehensive assessment, The Offshore Valuation produced by an informal collaboration of government and industry organisations co-ordinated by the Public Interest Research Centre (PIRC).
Drawing on published data, it puts the total practical offshore resource at 2131 TWh p/a from 531 Gigawatts (GW) of generating capacity, 406 GW of which would be wind capacity. England had 54% of the total practical resource (286.5 GW), Scotland 39% (206 GW) and Wales 7% (39.5 GW), with wind power dominating in each region.
PIRC point out that their scenarios "are neither predictive nor prescriptive" but calculate that, even if only 29% of the total resource was exploited, by 2050, the UK could have 169 GW of offshore capacity, supplying 610 TWh, equivalent to total electricity consumption by that time, making the UK a net electricity exporter.
Most of the supply capacity (116 GW) would be conventional sea-bed mounted offshore wind but there would also be 33 GW of floating wind turbines, further out to sea, plus 5 GW of wave, 9 GW of tidal stream and 6 GW of tidal-range projects. This would create 145,000 new jobs, provide the Treasury with £28 bn in tax receipts and reduce carbon emissions relative to 1990 levels by 30%.
Under a more ambitious scenario, utilizing 76% of the total practical resource, by 2050 there could be 406 GW of offshore capacity generating 1,610 TWh – about the same as total UK energy demand (not just the electricity demand) expected by then. That would involve an additional 212 GW of floating offshore wind capacity, while wave would rise to 14 GW, tidal stream to 21 GW and tidal range to 10 GW. The jobs total would rise to 324,000, most of these being for the floating wind turbines.
Some of the scenarios are clearly very ambitious. Even using just 13% of the total, to supply 50% of UK power would need a 34 GW mix of back-up/storage/interconnector links to balance variable supplies, and if higher percentages were used then more cross-channel interconnection would also be needed for exporting excess power – 85 GW for the 169 GW scenario and 321 GW for the 406 GW scenario.
So what would it cost? Using DECC figures, PIRC estimates that the 169 GW scenario would cost £443 bn but calculates that in 2050 it would earn £62 bn p.a in net electricity exports. The 406 GW scenario would cost £993 bn and earn £164 bn p.a. Most of the technologies cost £100–125/Mh initially but get cheaper (10% p.a "learning rates" are assumed), though wave and tidal range are more costly, at ~ £175/MWh.
Most of the technology exists or is under development, but floating offshore wind turbines are relatively novel and clearly play a major role in the more ambitious scenarios. As noted in my previous offshore wind blog entry, some floating systems are already under development but there may be limits to what can be obtained from them. The PIRC report states: "The technical limitations of current designs restrict floating wind to water depths of between 60m and 700m. There has also been some concern that it will not be possible to install floating wind beyond 100nm from the coast due to the time taken to get to and from the site." Also "access for installation and maintenance may be limited". Of course, the longer undersea grid links to land will cost more. Even so, the resource is huge. The PIRC puts it at 870 TWh/yr, with a further 660 TWh/yr available beyond 100 nm out. That compares to 180–240 TWh/yr for conventional fixed offshore wind, additional to current site allocations.
The resource for wave and tidal range (barrages/lagoons) is seen as much smaller, at 40 TWh/yr and 36 TWh/yr respectively but that for tidal streams is seen as more significant at 116 TWh/yr. This is larger than some previous estimates. The PIRC says: "Until recently the UK's practical resource had been estimated to lie within the range 4–30 TWh/yr. However, academic research has since highlighted uncertainty in both the underlying methodology and the assumptions used to estimate this resource, which has had the impact of increasing this range to 4–110TWh/yr." It notes that the "kinetic energy flux" method is widely used (e.g. by Black and Veatch) but Stephen Salter's "bottom friction" and David MacKay's "shallow wave" method both give a factor of 10–20 more. To navigate these uncertainties a "bottom-up" calculation was employed by the PIRC to get the technical resource and this was then reduced by 60% to provide an estimate of the practical resource. It was put at 33–200 TWh/yr, corresponding to a power density of 5 MW/k sq m and 30 MW/k sq m respectively. The average of this range – 116 TWh/yr – was used in the report.
The group behind the report, co-ordinated by the PIRC, included the UK, Scottish and Welsh governments, the ETI, the Crown Estate, E.ON, DONG, RWE Innogy, Mainstream Renewables, RES, Scottish and Southern Energy, Statoil, and Vestas. The government's Climate Change Committee also provided some support.
Tim Helweg-Larsen, director of research at the PIRC, said: "To discover that we own a resource with the potential to return the UK to being a net power exporter, and on a sustainable basis, is genuinely exciting, and a wake-up call to those in a position to foster the further development of this industry." But, to put the UK on a path that allows it to access its "substantial and valuable" resource, the PIRC said that Round 3 offshore wind grid connections would have to be made "super-grid compliant" to enable potential future electricity sales to Europe. The PIRC wants the government to take a leading role in the current EU super-grid negotiations, to ensure that the UK derives maximum value from its design and implementation. The domestic supply chain would also have to be developed to enable economic deployment at scale, while new financing structures would have to be created to support the scale and pace of the industrial growth required.
Peter Madigan, head of offshore renewables at trade association RenewableUK, said that "we have long been saying that the North Sea will become the Saudi Arabia of wind energy" and the results of this study "amply bear this out".
As I discussed in my previous blog entry on this topic, environmental impacts must of course be considered. For example, offshore systems have the potential for significant effects on marine wildlife, including dolphins, porpoise, grey seals and wildfowl but a range of environmental studies have been completed or are in hand and so far no major problems seem to have emerged that cannot be limited with by sensible design, location or mitigation measures. So it does seem that the UK could be on to a winner.
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