Climate Science Glossary

Term Lookup

Enter a term in the search box to find its definition.


Use the controls in the far right panel to increase or decrease the number of terms automatically displayed (or to completely turn that feature off).

Term Lookup


All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Home Arguments Software Resources Comments The Consensus Project Translations About Support

Twitter Facebook YouTube Pinterest MeWe

RSS Posts RSS Comments Email Subscribe

Climate's changed before
It's the sun
It's not bad
There is no consensus
It's cooling
Models are unreliable
Temp record is unreliable
Animals and plants can adapt
It hasn't warmed since 1998
Antarctica is gaining ice
View All Arguments...

New? Register here
Forgot your password?

Latest Posts


Spoiled ballots, spoiled views: an election snapshot from Powys, Wales, UK

Posted on 25 May 2015 by John Mason

It's a funny thing. One of the most viral news items concerning the UK General Election on May 7th 2015 came from my constituency of Montgomeryshire. Apparently, someone took the time and trouble to draw a remarkably detailed sketch of a penis in the box that they would have otherwise crossed had they been voting for the incumbent Conservative MP, Glyn Davies. In other headlines, three high-profile party leaders resigned within an hour of one another the following morning but everybody turned over and went back to sleep on that one.

I hasten to add that the artwork had nothing to do with me. I voted for one of the other guys – tactically, which in the context of Glyn's significantly increased majority turned out to be a wasted vote. I should have voted with my heart – for the Greens or Plaid Cymru. Unlike the other parties, at least I can state that I have met the leaders of the latter two in person and have found them to be – well, real, passionate and principled people, as opposed to the used car salesmen stuffed into suits to look “respectable”, that tends to be the norm over here.

So, what has this to do with climate change, readers may well be asking? Quite a lot in fact. What troubles me about the outcome of Election '15 is that voters, like turkeys vaguely approving the advent of Christmas, seem to have voted for more Business As Usual. But they have done so in a political atmosphere so clouded with media-served misinformation that it is hard to know where to start with the debunking. So let's put UK politics to one side now and stick to our speciality: dealing with another channel of misinformation, that related to global warming. Take a look at this letter, from the latest issue of the County Times, a weekly newspaper that covers Powys, the larger local authority area of which Montgomeryshire is a part:

letter, County Times

Just where did the writer get these ideas from? The first half of the letter is about a part of the globe that is warming so quickly compared to anywhere else that the phenomenon even has its own special term, Arctic amplification. Take the first major error, column one, paragraph two, line five. Has the writer forgotten or not realised that the Arctic sea-ice minimum record was utterly smashed in 2012? The minimum then was 3.4 million km2, against a 2007 value of 4.28 million km2 and a 1979-2000 average of 6.75 million km2. Nobody expected year-on-year record meltdowns: it hits a record, then doesn't for a few years, then the record is broken once again – it's a bit like the surface air temperature record in that respect. In this age where people seem to expect instant results, global warming goes against that: it is a slow, stepwise process. This animated graph, by Dana, spells it out clearly:

arctic sea ice extent

above: September Arctic sea ice extent data since 1980 from the National Snow and Ice Data Center (blue diamonds).  "Recovery" years, meaning years when the sea ice extent is greater than the previous year, are highlighted in red. Every time they occur, the usual suspects are out and about claiming them to be "proof" that global warming has stopped. But wait for the trend-line!

The writer then goes on to bemoan that The Archers (a popular radio soap-opera also known as “an everyday story about country folk”) is now suffering from Global Warming. This, I make an educated guess because I listen to it, must be a comment about the fictional village of Ambridge recently getting a heavy dose of what the good people of the Somerset Levels had to endure for real for months on end in winter 2013-14: water, a great deal of it and all in the wrong places. The writer also states that  "no warming at all has occurred for two decades". That makes it, unless I've really flunked my maths, no warming since 1995. Hmm. 1998, 2005, 2010 and the record-breaking 2014 were the hottest years on record.

But such sets of statements raise a serious question: how can people end up believing and repeating such clearly erroneous things? The correspondent in the above letter would only have to have searched a little online to have located full Arctic sea ice datasets on extent, area and volume. They would then have known that it has not recovered since 2007: the long-term trend is very much downwards and in addition February 2015 saw the lowest Arctic sea-ice maximum of the satellite record.

It's too early to call this year's Arctic sea-ice minimum, of course, but the word “recovery” is only too readily bandied-about by characters like David Rose who is fond of getting paid to write climate change misinformation in the UK tabloid, the Daily Mail. It's on a level with the utter junk about the UK's weather that makes up Daily Express (another UK tabloid) front pages in between articles about rising house prices, Princess Diana and miracle cures for cancer. In the UK, George Monbiot and I have been campaigning against such nonsense for some time, most recently here and here, but the tidal flow of complete guff continues unabated. And when people are repeatedly misinformed about a topic, they end up bereft of the tools with which to come to an evidence-based conclusion. How can they then make the best and most logical decisions? That's bad enough in party politics. In the field of energy and climate and the long-term future of Wales (or for that matter, Planet Earth), it is far more serious.

a spoiled view?

above: spoiling the view? Wind turbines in the Montgomeryshire uplands. Photo: author.

Montgomeryshire is an interesting constituency in more ways than one, and the same can be said for the bigger overall county of Powys. With extensive uplands, exposed to the prevailing sou-westerlies that feed in off the Atlantic, Powys has attracted a lot of investment in wind energy. It has also attracted a lot of people from the cities, keen to invest in property and live out retirement in the countryside. A proportion of them - and some local people - don't like looking at wind turbines. And there is the crunch-point. David Cameron recently saw it and swiftly took advantage. During the election campaign, he said the following with respect to Powys:

“You would have to ask the environment secretary who took that decision and that was a decision for him. However, I want to make it clear that if there is a Conservative Government in place we will remove all subsidy for on-shore wind and local people should have a greater say. Frankly I think we have got enough on-shore wind and we have enough to be going on with, almost 10 per cent of our electricity needs, and I think we should give local people a say if they want to block these sorts of projects. The only way to stop more on-shore wind is to vote Conservative there is no other party with this policy. We are saying very clearly we would remove the subsidy and give local people the power to say yes or no. This would end the growth of on-shore wind and if that’s what you care about you must vote Conservative.”

And the rest, as they say, is history. But there's a minor rainbow under this dark cloud in that Cameron has appointed Amber Rudd as Energy and Climate Change Secretary in his new Cabinet. Liz Truss remains in her post as Secretary of State for the Environment, Food and Rural Affairs. This is to be applauded: regular readers will recall that one of the previous Environment Secretaries serving under Cameron sounded as though he was on loan from the so-called Global Warming Policy Foundation (see for example our debunking of him here). Neither Rudd nor Truss is a climate change denier – far from it, and I wish them well in their posts. But I'd better come to the main point.

People who object to wind-farms tend to do so because they perceive that they will spoil the view and/or lower property prices. They seem to think that somebody else should have to look at the means of electricity generation whilst they merely use the stuff as they see fit. I have some news for such people that is rather more significant in the long term. If any of them should read this, I'll start with a question. What makes the ancient market-town of Machynlleth (my hometown and a community that I love) unique in Powys?


above: the historic market town of Machynlleth. Photo: author.

The answer is that in the case of unmitigated climate change, it is the only town in Powys that will be wiped off the map. I mean that quite literally. Not in my lifetime, but the coming together of the circumstances that will allow it to happen is happening on our watch and thus far little has been accomplished to put a stop to that. People, it seems, prefer to complain about wind turbines spoiling the view. But the nitty-gritty is as follows. Much of Machynlleth stands at between 6 and 25 metres above sea-level. That's mean sea-level of course, not taking into account that the local tidal range varies between 3.4 metres at high water on the smallest neap tides to 5.7 metres at high water on the biggest spring tides. Storm surges can also add a metre or two of extra water. We know that ice-sheet meltdown is accelerating, especially in Western Antarctica, and it will be difficult to stop it any time soon. This is because inertia in the climate system and the carbon cycle means that the global mean temperature can only decline slowly (on a millennial scale) even after greenhouse gas emissions have ceased. In turn, that raises the question of how much sea-level rise can be expected as a consequence of those raised temperatures.

Levermann et al (2013), looking at past warm periods during the Pliocene and the Quaternary, including the last interglacial, have calculated that for every degree Celsius of warming above preindustrial levels, 2.3 metres of sea-level rise can be expected over the next 2000 years. The pace of that rise is uncertain: in the 20th century, with 0.8C of global warming, 0.2m of sea-level rise occurred, mainly due to loss of glaciers and thermal expansion of sea water with parts of the polar ice-caps playing an ever-increasing role. On the basis of Levermann et al, getting on for 1.65 metres of additional sea-level rise can be expected in the coming decades of this and the next century due just to the warming to date. The "safe" warming target of 2C above preindustrial levels produces a total of 4.6 metres of sea level rise, or 4.4 metres above present levels. Failure to contain temperatures at that level brings an increasingly widespread risk: a warming of 4C brings with it 9.2 metres of sea level rise and so on.

It's also worth bearing in mind that the process doesn't simply stop after the 2000 year period under consideration. That's because of a parameter known as the "ice threshold" which is the level of atmospheric carbon dioxide below which ice-caps can start to form on a non-glaciated, cooling earth, as was the case in the mid-Cenozoic. Royer (2006) places the ice threshold at around 500ppm carbon dioxide - with levels consistently above that, the planet simply deglaciates over the next few thousand years with tens of metres of sea level rise as a consequence.

The current rate of sea-level rise is just under 3 millimetres per year (or 0.3 metres per century - and accelerating), but we know that during other deglaciation events, typical rates of 1-1.5 centimetres a year and exceptionally (as in the case of Meltwater Pulse 1A) 5 centimetres a year have occurred (see for example Foster and Rohling, 2013). That's typically 1-1.5 metres a century, and exceptionally 5 metres a century, or 20 metres in 400 years. Delivery time uncertain, but delivery certain, as one of my colleagues recently put it. 

sea level rise and the future of Machynlleth

above: Machynlleth, after 10 m and 20 m of sea-level rise. Grid squares = 1km

Yes, we (well, some of us) know what is possible. Whether an extreme scenario like Meltwater Pulse 1A occurs or whether the process takes many more centuries as suggested by Levermann et al is beside the point. With unmitigated climate change, Machynlleth will be wiped off the map either way. And long before then, low-lying coastal settlements will be under aggravated threat. Down at the open coast is Borth, the beach-side onetime fishing village, now popular holiday destination. It is right in the firing line of sea-level rise, as are dozens of similar towns and villages. Some places have had worse news. It has already been decided that the village of Fairbourne, up the coast to my northwest, will “enter into managed retreat in 2025”. Fairbourne is one of around 50 of the coastal communities of Wales that have been similarly listed. They are to be abandoned in the face of sea-level rise. Now that's what I call a spoiled view.

ten metres of sea level rise

above: the effects of ten metres of sea-level rise on the Cardigan Bay coast of Mid-Wales.

The issue is, of course, not unique to Wales. A glaring example is Florida (below - from NASA Earth Observatory). The right-hand graphic shows the amount of land that will be wiped off the map with 5m (darker blue) and 10m (lighter blue) of sea-level rise. A lot of Florida is less than sixty metres above sea-level. You'd think they'd be spearheading the campaign to decarbonise. An existential threat not just to a few coastal towns but to a whole State. The official policy response? Ban all public servants from using the terms "global warming", "climate change" and "sea-level rise" in any official communications.

Florida - terribly prone to sea level rise

It really makes one wonder what some people have voted for.

0 0

Printable Version  |  Link to this page


Prev  1  2  

Comments 51 to 85 out of 85:

  1. ^ The article you reference indicates that they are not subsidies but tax breaks - a subtle but important difference. As I understand it, such tax breaks are available to any business for R&D, research, or in this case, exploration activities.

    You say that 'valuing visual impact so highly ... is morally suspect' - I would counter that it is morally suspect to value it so little as to permit destruction of rural serenity, but both of course are purely subjective points of view.

    0 0
  2. FWIW: I grew up in a National Park and then lived on a farm till my teens. I loved seeing the windmills when driving from Sydney to Canberra or Stockton to San Fran. It's more than simple aesthetics though, while I've always liked windmills of all varieities, I like them even more for what they represent.

    People who dislike what they represent, dislike seeing the windmills.

    0 0
  3. Rural serenity slips way down my value system compared to human life and justice but as you say, that is subjective. On the plus side, it is good that you are prepared to pay very much more for your energy. Did you find evidence that MacKay's estimate for marine power is too low?

    Tax breaks and subsidies amount to public money for private enterprise. It costs tax payers however it is phrased and relevant to this debate, it results in continuance of FF enterprises that would not happen without the price support. In my view, better governance is kill all subsidies/tax breaks, price carbon accurately, let the market determine the best way supply the need.

    0 0
  4. Langham @51:

    "You say that 'valuing visual impact so highly ... is morally suspect' - I would counter that it is morally suspect to value it so little as to permit destruction of rural serenity, but both of course are purely subjective points of view."

    Try as hard as I like, I can find no reference to a right to rural serenity in the Universal Declaration of Human Rights.  Nor yet have I seen any concern for such a right in the decisions of government with respect to the siting of mines, fracking operations, airports etc.  I have to wonder what it is about wind turbines that is so destructive of rural serenity that they should be banned, while open cut coal mines are apparently OK (because, apparently not so destructive of rural serenity).

    In fact, it looks to me very like this concern for "rural serenity" is merely a personal preference which is raised to the level of a moral rule, base purely on rhetorical expediency.

    0 0
  5. Tom - Where in my postings was I arguing in favour of mining, fracking, airports etc? You're wandering way off topic - the thread is about wind turbines, not those other things.

    Nor do I understand your reference to the UDHR (a text written decades before wind-farms had even been thought of). Because something is not listed there, it's not important, is that the point you're trying to make?

    It may be of no interest to you, but the concern for rural serenity is a real one, for me and for many other people besides. It is under threat from many sources, but the article makes some (to my mind) rather glib and specious comments about wind-farms and those who oppose them, and I wish to rebut what it says while also pointing out the superior merits of the sea-based alternatives.

    I find it rather hard to fathom the reasoning processes of people who are apparently sufficiently concerned about the environment to acquire some superficial knowledge about climate change, and yet are perfectly happy for the countryside - which is the nearest thing we have here to a natural environment - to be laid waste for no good reason when there are perfectly good alternative options to hand.

    0 0
  6. Langham @55, you personally may have a preference for "rural serenity".  Urban dwellers, on the other hand have a preference for reliable power supply.  They are willing to pay for that supply by paying for wind farms.  You, however, are not prepared to pay for your "rural serenity" by buying up the land around your rural dwelling to ensure it is not used to develop wind farms.  Rather, you are appealing to your desires as generating a right which somehow trumps the rights of urban dwellers to provide for their power needs at a reasonable price.  In fact, you are asking those urban dwellers to pay more so that you can enjoy your idiosyncratic desire for "rural serenity".

    As I see it, you either have to flesh out your argument in moral terms such that "rural serenity" is a fundamental right; or accept it as a personal value which therefore need not be respected in the market economy by other people seeking to pursue their personal values.  You don't get to have a quid on each corner - to maintain it is just a personal value, and therefore inarguable, but to treat it as a fundamental right so that it is normative on other people.

    Least, ways, you can try doing so - and I can dismiss such bullshit arguments as the irrelavancies they are.

    0 0
  7. You have yet to establish "the superior merits of the sea-based alternatives" other than that you dont have to look at them. So far they are an extremely expensive nascent technology which in no way can provide enough power to replace land-based wind turbines. I am happy to be proven wrong but please provide a reference.

    I think you are also mistaken that concerns about climate change = environmentalism. I am mostly concerned that we do not damage the critical infrastructure that underpins our civilization. Hardly "no good reason". 

    I will let Tom make is own argument, but rural serenity does not appear to be a human right whereas our unwillingness to ditch FF is certainly depriving others, minor users of FF, of rights they  have. It's about priorities. 

    The situation for non-FF energy in UK does look tough. I'd be looking closer at next gen nuclear I think if I was in your situation.

    0 0
  8. Tom @ 56 I think you are writing from a rather North American perspective - it is not a case of city dwellers' rights or wishes being juxtaposed against those of rural dwellers, nor - in the UK - is it necessarily those with the biggest pockets who get to decide what happens. In fact I don't think market forces come into it, or at least not in the crudely direct way you seem to imagine.

    The Cameron quote in the original article is a good indication that the present government - presumably in response to the wishes of the electorate generally (or as it may be, Conservative voters generally) - appears at long last to recognise the need to call a halt to further land-based wind-farms.

    Actually I do not have to 'flesh out' my argument concerning the right to unspoilt countryside - to rural serenity. The imperative need to protect our countryside - at least some of it - has been recognised in law here since at least 1949 with the National Parks Act, and arguably goes back much further, and is a right that is enjoyed equally by city dwellers and those living in the countryside. And lest there be any suspicion that I may be arguing from a NIMBY standpoint, I will point out that I live in the centre of a Midlands town - although in fact it is as good a place as any in which to contemplate the signal importance of being able to enjoy rural serenity, even if only at weekends.

    Scaddenp @ 57 the superior merits of the sea-based alternatives are briefly mentioned in my earlier posts, and include the certainty of tidal reliability and the much reduced need for back-up capacity for windless days. It is hardly 'nascent technology' - it is already up and running (has been for at least 60 years). Yes, expensive, but then so are wind turbines, whose economics seem utterly dependent on subsidies.

    0 0
  9. An article pointing out some of the background and benefits of tidal power:

    0 0
  10. One curiosity here in Central Wales that I've never seen a satisfactory answer to: the very same hills are home to a patchwork of conifer plantations. Artificial, totally not natural, lifeless on their dark floors, like the black squares on a chessboard and anathema to the landscape photographer. They are indeed ugly. Yet none of the people that complain about wind turbines ever mention them. Is it because turbines represent something else - the need to redefine energy generation, I wonder?

    0 0
  11. Langham, I'm going to turn it around and suggest that you are writing from your own perspective. For most people, wind farms are not considered a 'blight on the landscape'. Indeed, many find them beautiful. They are actively sought by rural communities in the United States, Denmark, Germany, et cetera. Even in the UK more than 80% of the population supports wind energy. Scotland is pushing towards 100% renewable energy... largely based on the popularity of rural wind power.

    In short, you are projecting your minority view on to the UK and the world at large. When, in reality, the vast majority disagree. You are also simply incorrect that wind power is "utterly dependent on subsidies". Subsidies obviously help to accelerate growth, but wind power is growing in many parts of the world even without subsidies... as it would continue to do in the UK even if all wind power subsidies were removed while (much higher) funding for other power sources was left in place.

    0 0
  12. @61, Could you say where you get your figures from? I am not aware of a national referendum having been held on the subject, so you are I suspect extrapolating to an enormous degree when you claim to know what 'most people' think.

    Both the Guardian and FT reference independent polls, each of around 2,000 people, concerning their attitude to local wind-farms. In the Guardian poll, 48% were in favour; the FT figure is 62%. So definitely, for those 2,000 people, wind-farms are preferred to say fracking nearby, but I'm not sure where your figure of 80% of the UK population can come from. I think you are claiming to speak for the 'vast majority' on a rather flimsy basis.

    Of course were I of a similar mind I too could 'turn it around' by means of extrapolation and obfuscation, and say that the one party that had pledged to end subsidies for wind-farms, the Conservatives, won the recent general election - ergo the British public are not in favour of wind-farms. 

    Being an advocate of wind-farms needn't bar one from being open-minded enough to appreciate their various manifest drawbacks, nor to giving consideration to other - possibly better - means of achieving the same end. The supporters of wind-farms who post here seem, opn the whole, utterly dogged in their determination that wind power is the only way to avert catastrophe - is this tunnel vision or monomania?

    0 0
  13. Langham,

    From your reference to support tidal energy:

    "Although the potential clearly exists, the technology is presently still in a pre-commercial phase and only a hand full of devices have so far been tested at full scale in the ocean. No single turbine design has been converged upon so far and there are many aspects of the technology and operation that are not yet well understood."

    Tidal power is not ready for commercial application.  What is a reasonable time line for untested technology?  Tidal energy turns off for 30 minutes every 6 hours as the tide turns.  How is that reliable?  In any case, few areas in the world have siginificant tidal energy available.  Wind energy has decreased in cost 25% or more since your reference was written (it is from Jan 2013).  It can be implemented in most countries world wide.  Can you provide a link that estimates current costs for tidal energy?

    It seems to me that pinning our hopes on a technology that is not ready for commercialization and is only available in only a few areas of the globe is not a very good strategy.

    0 0
  14. Langham, this 2010 Harris poll found 82% in Great Britain favoring more wind power (question 5). I note you cite values for "local" wind farms, which is a slightly different issue due to NIMBYism, but even so you concede my point... more people support than oppose wind farms. Even wind farms to be built in their area.

    As to the unfounded insults and obfuscation... yes there are 'drawbacks' to everything. However, the supposed deficiencies you have cited for wind farms are mostly false and/or matters entirely of opinion, where your view is in the minority.

    0 0
  15. @ 63. You have selectively quoted a reference to a specific type of turbine still under development. A variety of other types have been in operation for decades - in fact for a lot longer than wind turbines. HEP has of course been with us since the 19th C and the tidal barrage on the Rance Estuary in Britanny has been producing electricity since 1966, so while utilising tidal energy is a tried and tested technology, it is one where there remains enormous potential for further development. 

    I have to say, I'm a little surprised by the apparent depth of your ignorance on the subject evident in your wildly inaccurate claim that 'tidal power is not ready for commercial application', given that it has been in commercial use for 50 years. 

    Yes, I understand about tides turning, but the point is that this happens with extreme predictability, and at different times along our coastline, so several strategically sited schemes would guarantee a constant supply of non-flickering electricity. Even if (as I suspect some here would like) the entire country was covered in wind turbines, there would still be nothing remotely resembling a steady and reliable supply of electricity.

    The conditions in Britain happen to be particularly suitable for using tidal energy, but there are many other parts of the world where it would also be applicable. Not the tideless Mediterranean, naturally, and not landlocked countries but a cursory glance at a globe should indicate areas of greatest potential. Even Mr Mason's map of inundated Cardigan Bay shows several bays that could profitably be used.

    I've explained enough I think - I suggest you do your own Googling to learn a bit more on the subject.

    0 0
  16. @64 The poll you direct me to (just over 1,000 people polled) makes the point rather well that in each of the countries polled, the majority of people are unwilling to pay more for energy from renewable resources. People are fickle, aren't they?

    But personally, I wouldn't place too much weight on a poll of 1000 people in a country of 65 million - the opposition to wind turbines is greater than you seem to imagine, and for valid reasons. I believe this is now being recognised in the UK, hence the change in government policy.

    0 0
  17. Langham @66:

    "But personally, I wouldn't place too much weight on a poll of 1000 people in a country of 65 million"

    That only shows how little you know about samples sizes and uncertainty.  Specifically, with a sample size of 1 thousand, a population of 65 million, and a result of 82%, the uncertainty is plus or minus 2.38% (95% confidence interval).  It may give you great confidence in the strength of democratic feeling against windfarms that as little as 79.6% of the population - but it hardly favours your view.

    I, however, prefer to use more up to data surveys, such as this one from March, 2015 which found 65% of British citizens are in favour of more onshore windpower.  (Sample size: 1981, uncertainty +/- 2.1%)

    What the Conservative party is responding to in moving against onshore wind is not public opinion, but the localized opinion in particular constituencies.  While only 12% (+/- 1.43%) of British citizens opposed onshore wind as March 2015, a disproportionate number of them would have been Conservative voters likely to swing to UKIP over the issue.  Probably also a disproportionate number of them would have been found in specific marginal electorates.   It is certainly not responding to public opinion as such, which has been firmly in favour of onshore wind for years.

    0 0
  18. Tom Curtis @ 67: dodgy methodology (as I cannot help thinking) or not, the fact remains that just because x number of people approve or are in favour of something, that in itself may often be insufficient to make that thing happen, never mind make it the right thing to do. For example, 50 years after the abolition of capital punishment in the UK, majority public support favoured its reintroduction - but it ain't going to happen.

    0 0
  19. Langham - As I said earlier, "We'll have to see how UK policies and projects develop based on costs, lead times, and public opinion..."

    Also note your comment here: "...the majority of people are unwilling to pay more for energy from renewable resources..."

    Marine power levelized costs are at least twice that of onshore wind, and the public opinion surveys indicate that a solid majority of the UK public is in favor of expanded wind development. I expect that there indeed will be more windmills, despite your NIMBY (or NIMV - Not In My Vista?) opinion on the matter, and despite your offhand dismissal of polls. 

    0 0
  20. KR @ 69 That analysis depends very much on what form of tidal power the comparison is made with. Tidal barrages are admittedly highly expensive projects; however tidal stream systems are much simpler and less expensive, and given the inherently much greater efficiency of systems that use flows of liquid rather than air, stream systems can be smaller than land-based turbines, yet more powerful, and as for any tide-based system, there is little need for back-up generation capacity.

    I acknowledge that costs remain an issue; nevertheless, current government energy policy gives me some cause for mild optimism.

    0 0
  21. Langham - I call it nascent because installed base is tiny - and I notice that your BBC source does too. I also note that their estimate is 20% of current electricity requirement, not total energy, but in future, we have to power transport with electricity too. Mackay's estimate of around 200Twh looks very optimistic to me. No one has come up with even a design yet for stacking tidal stream turbines in a way that they can lifted out for maintenance that I am aware of. By there very nature they are more expensive than onshore wind - they have to survive in a marine environment, maintenance is much more difficult to do, delivery structures have to be built underwater as well. If wind needs subsidy, then marine needs it even more.

    But more importantly, you need both marine and onshore wind to supply UK without nuclear.

    By way, here in NZ, subsidies are dirty word and yet wind farms continue to be built.

    0 0
  22. The BBC article also points to a royal society publication which is very interesting. It includes detailed studies on tidal stream resources considered by MacKay and comes up with lower numbers. Looking at Isle of Mann, Yates concludes "Total annual energy output simulated, at 14.5 TWh, is highly encouraging though this remains provisional, pending further validation testing. It also takes no account of practical considerations and constraints"  MacKay assumed 17.6TWh for the same region. The same paper puts tidal barrage resource at 50Twh, about the same as MacKay (55).

    I'll stand by original statement - you cant replace onshore wind with offshore tidal streams. The resource isnt big enough and is much more expensive.

    0 0
  23. Scaddenp - here is a video showing one tidal stream system. You'll see it rises out of the water for maintenance. Maintenance naturally is more complex, but then it's not exactly straightforward for land-based systems either. The UK now has a number of quite large offshore wind-farms so experience in their maintenance is developing.

    As far as I am concerned, every new offshore wind-farm or tidal stream system equates to one less onshore wind-farm (perhaps more so, given that winds are more constant away from land), so I'm very much in favour of them.

    0 0
  24. Langhorn, I am aware of current technology. However, extracting the full power available from tidal streams requires stacked one on top of another which has yet to be achieved as far as I am aware. However you cut it, offshore systems are inherently more expensive to maintain than onshore.

    "every new offshore wind-farm or tidal stream system equates to one less onshore wind-farm"

    And as I have repeatedly pointed out, this is not true. You cannot get off FF on marine power alone. You also need all the onshore wind as well. You do not have an easy choice. You can give up your rural serenity (small price compared to what some will pay for FF use), you can accept nuclear, or you can accept the consequences of a warming climate. How many refugees from the great deltas do you think the UK should accept given it's historical contribution to the elevated CO2 levels.?

    0 0
  25. Scaddenp @ 74.

    UK government energy policy does not envisage reliance on renewables to the extent demanded in your probably unachieveable and certainly unrealistic scenario - see the recent output from DECC on the subject, which clearly envisages a mixture or energy sources, less reliant on FF than at present but also making use of biomass and CO2 sequestration technologies - as well as nuclear.

    In the real-world circumstances, at the present time, it may well be that the UK and perhaps other nations turn increasingly to marine power, where this is available, to complement or replace land-based wind-power systems - and my assertion is absolutely true. The UK has a target for renewable power, and if some of that is met from marine sources, then the land-based component is reduced in direct proportion.

    Perhaps in certain middle-eastern or equatorial countries with abundant sunshine and sparse countries it is possible to envisage an energy policy based entirely on renewable (in this case solar) power, but in densely populated European countries, 100%  reliance on renewable energy generated locally, with present technology, is just an idle pipedream.

    The concept of rural serenity seems, for reasons which are obscure to me, to aggravate some here. Nevertheless, a sufficient number of people in the UK and I imagine elsewhere prize it sufficiently that, while it would be delusional to imagine there can be any form of complete embargo on all rural development -  clearly there isn't - nevertheless any government or planning authority is ill-advised to interfere with it lightly.

    0 0
  26. Good luck convincing your countrymen then to accept extremely expensive technologies like marine and CCS to preserve your rural serenity. Why does it aggravate people here? Well because it seems such a trivial and highly subjective value compared to the stakes involved. Upholders of this value are usually to the fore in slowing down a move away from FF - costing other people far away. If you are prepared to pay for it by taking on nuclear and extremely expensive renewables, then that is a choice I am quite ready to grant you. Good luck.

    0 0
  27. ScaddenP - you live in a country with a very small population and easy access to abundant, and as far as I am aware, very nice countryside, so I can only assume that it is something you take completely for granted otherwise you would not dismiss my values as 'trivial and highly subjective'. My country is over-populated already so there can be no question of us being reasonably expected to receive those 'refugees from the great deltas' you mention (Nile? Mississippi? Irrawaddy?), they will just have to find higher land that is slightly closer to home. There are plenty of mountain ranges.

    0 0
  28. The entire country of Bangladesh is less than 7m high. Telling people they have move or drown so you can enjoy the benefits of FF while they are largely deprived of is doing nothing for your case. I have no sympathy for an argument whereby one person gets a benefit and another pays for price. The best solution is stop sealevel rise by getting off FF immediately. Otherwise you are morally obliged to help the people affected by your emissions.

    I similarly do not equate peaceful countryside with matters of life or death.

    0 0
  29. Langham,

    Hundreds of millions of people are farmers in the great deltas of the world.  Suggesting that they can move to mountains is absurd and demonstrates that you have no difficulty killing off these hundreds millions of people for your own short term pleasure.  All habitable areas of the world are already settled.  Every country still habitable in the world will have to take in many refugees, there are too many people under 5 meters sea level to go anywhere nearby.

    0 0
  30. @ 78, 79: millions of refugees from drowning nations? At present that is a highly speculative scenario. To some it will seem you have fallen prey to the delusional paranoia/mass hysteria that is to be found on the fringes of the climate change debate. 

    I would hazard a guess that a significant majority of the population in developed countries remain utterly indifferent, if not outright unconvinced, of the need to cut back on FF (such reductions as have occurred can reasonably be attributed to fiscal incentives, technological improvements, and pain-free feelgood impulses rather than any conscious, altruistic forgoing of consumption); however, preach away by all means.

    0 0
  31. If you think IPCC estimates of sealevel rise are delusional, then your desire for no change to the countryside is blinkering your outlook. The delata threats are from increasing salt incursion, coastal erosion (where small rise in sealevel can eat soft sediment fast without need to drown it) and increased danger from storm surge. These problems are happening now with only 20cm.

    I have no doubt that there are many selfish indifferent people in the western world. If you chose to stand with them, then dont expect much sympathy for your bleating about peaceful countrysides. I can only hope that there are more responsible, rights-respecting individuals making the actual decisions.

    0 0
  32. Langham,

    Please provide a citation to support your wild claim that millions of refugees is speculative.  You are making an uniformed assertion without any basis except your personal guess.

    This Realclimate post documents what sea level rise experts thought in 2013.  They estimated 70-120 cm of sea level rise (likely, with a chance of much more rise) by 2100 for RCP 8.5.  Since that time new data from the West Antarctic indicates much faster sea level rise.  This NY Times article  documents that a 1 meter rise would displace 20 million people from Bangladesh alone.  Count another 5 million at least from Florida.  This paper estimates 6 million refugees from a 1 meter rise of the Nile delta.  The Mekong delta is the same.  The second meter will displace many more people than the first meter.  Worldwide would be in the hundreds of millions.

    Your claim that millions of sea level rise refugees is speculative is simply an indication that you are uninformed about this subject.  Go do your homework and then come back and we can discuss it.

    Perhaps all these refugees can resettle in the mountains near you, since those mountians are currently not occupied and all the land near Bangladesh is already settled.  That would certainly look better than windmills!

    0 0
  33. With regard to the comments about wind turbines up thread, I recently came across this article which I thought I'd share. It discusses a new design of turbine without blades, which is, apparently, cheaper to manufacture, kinder to birds, and works better when units are placed closer together. Whether or not they are more aesthetically pleasing or not is, of course, subjective !

    They are crowdsourcing at the moment, should you wish to encourage them. Or, of course, they may be snake oil ...

    0 0
  34. @Daniel Bailey 28
    You might be aware you first graph comparing avain death by power source ahs been reused various places online like here. I'm wondering where the source for death by nuclear came from. Nuclear advocates often level this myth about wind turbines and it would be nice to have a reliable source to say well, if it's bird deaths your care so much about then you'd advocate replacing nuclear with wind power. Thx Alastair

    0 0
  35. wideEyedPupil, given that I wrote the article you linked to, I'm not particularly worried about it. 



    1. The graphic you're interested in was taken from this source
    2. Nuclear power does have it's place, but as one of many wedges, and not the entire busload.
    3. But then, renewables can drive the busload by themselves, as it turns out.
    0 0

Prev  1  2  

You need to be logged in to post a comment. Login via the left margin or if you're new, register here.

The Consensus Project Website


(free to republish)

© Copyright 2022 John Cook
Home | Translations | About Us | Privacy | Contact Us