Climate Science Glossary

Term Lookup

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

Settings

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

Settings


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 Donate

Twitter Facebook YouTube Pinterest

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...



Username
Password
Keep me logged in
New? Register here
Forgot your password?

Latest Posts

Archives

Climate Hustle

Grappling With Change: London and the River Thames

Posted on 3 August 2010 by doug_bostrom

Samuel PepysIn 1666 Samuel Pepys watched  from “a little ale-house on the Bankside” as much of London burned to the ground. Pepys was no stranger to  nature and mankind colluding to produce drama, indeed his diary seems peppered with calamities. The year before London went up in smoke Pepys chronicled the Great Plague of 1665. On 20 May of 1663 the prolific diarist noted a combination of rain, wind and tide leaving important portions of the city navigable only by boat:

 “Then to Westminster, where by reason of rain and an easterly wind, the water was so high that there was boats rowed in King Street and all our yard was drowned, that one could not go to my house, so as no man has seen the like almost, most houses full of water.”

Without the River Thames there would be no London but like many great cities living with a river the relationship of the two can as tempestuous as it is intimate. This is London so unsurprisingly  the “little ale-house” from which Pepys viewed London's incineration is still in business today, operating as “The Anchor.” One may purchase a pint of “London Pride” ale in The Anchor, saunter out to the Embankment and not 75 feet from the door get a direct view and appreciation of London's fruitful but  perilous marriage with the River Thames and the estuary and ocean it feeds. Depending on time, tide and winds, looking over the embankment directly in front of The Anchor water is visible directly below at a vertical distance ranging from perhaps 2 to 10 meters. Across the river, the seat of the United Kingdom government and a substantial fraction of the world's economic brain is situated in similar proximity to copious amounts of water, benign or destructive depending on whether the flow remains inside or outside of the Embankment.

The  “Embankment” creeping into this narrative needs explanation. Pepys' ale-house viewpoint is located in a neighborhood of London's Southwark Borough known as “Bankside”; the Embankment is an engineered physical feature of London with roots extending back to Roman times and is a crucial part of London's infrastructure. When this region first attracted settlement, leading to the nurturing of a city of some 7.5 millions, nobody knew of the long term behavior of the conveniently located plain next to the river. London as it turns out is largely situated in a floodplain steadily sinking in relation to sea level yet substantial human investment preceded familiarity with the local environment. The result has been a never-ending battle to keep the River Thames contained within its channel, a ceaseless tightening of the grip of water on London  and London's constraints on that water itself even as London thrived on the benefits such a river can bring.

Thames Embankment Improvements 1879-1953 

Thames Embankment Improvements, 1879 (1) to 1953 (4)  (After Defra/Environment Agency Joint R&D FCERM Programme R&D Technical Report FD2319/TR )

Conurbations such as Greater London expose and grow risks even as they sprout and nurture population and architecture. Ideally newly emerging risks will be tackled by public cooperation to the extent they are intellectually, physically and economically tractable. Thanks to efficiently applied public policy in the form of better construction and city planning standards, London's risk of burning from unchecked fire is reduced, just as public policy informed by science has essentially eliminated the chance of contracting plague, or cholera from a drink of London tap water.

Government acting in the public interest has also addressed the risk of flooding on the scale witnessed by Pepys yet the optimal solution to this threat is in a continual state of evolution as our understanding of influences on the behavior of the Thames improves.  The flood control and emergency response schemes created during the latter part of the 20th century and now protecting London couldn't account for impacts on sea level and storm intensity from climate change, an oversight borne of circumstantial ignorance, now being dealt with in planning revisions and upgrades to London flood management policy and technical solutions.

There is a possibly apocryphal story of King Cnut (aka “Canute”) setting up his throne on a beach of what was in the 11th century Thorney Island and commanding the river tide to stop, which order it failed to obey. Cnut is said to have done this as an example to his courtiers of the limits of temporal power. Real or not, Cnut's demonstration resonates thanks to its simple lesson of the limits of human power against natural forces. Today Cnut's Thorney Island is no longer an island and is the location of London's Westminster Palace, the location of the House of Commons and House of Lords and the functional seat of the United Kingdom government.  Despite sinking land and a rising river, Westminster remains high and dry; engineers, money and sheer stubborn human nature have accomplished what Cnut's command could not. Our power to resist the forces of the River Thames and its relationship with wind and ocean tides has prevailed, occasional events such as what Pepys described notwithstanding. What in fact are our limits here, and what for that matter do we do when it turns out we are not only battling Nature but ourselves, when we learn that defeat may come by our own hand?

London has so far existed in a delicate balance with the River Thames, locked in a pas de deux between man and nature. This performance is made possible only by having enough money to spend over a sufficiently long period of time so as to accommodate the river's inexorable rise in relation to the city. When Pepys saw Westminster surrounded and filled with water, the Thames with the aid of the wind and tide was tipping the scales beyond London's engineered capacity to maintain its desired relationship with the river; the investment in keeping the river at bay was insufficient for the variations of river behavior envisioned by Westminster's planners.

London has steadily invested in and grown not only its capacity to coexist with the River Thames but has also simultaneously vastly increased the stakes at play in this game of push and shove, which is in part a matter of probability, of chance.  Leaving aside the civil mind of the United Kingdom as it is embodied at Westminster Palace, a brief lateral distance and no vertical distance at all from Pepys' Anchor and the Embankment  lies the entrance to the London Bridge tube station. This Underground station is accessed through multiple grade-level entrances followed by very long escalators leading deep below the surface to the transportation system that allows London to function. It does not require a vivid imagination to picture what would happen in the event of water overtopping the Embankment and making the short trip to London Bridge Station, just one of many facilities and assets similarly situated and equally accessible to uncontrolled water.  These include 85,000 properties, 400 schools, 16 hospitals, 8 power stations, 30 mainline railway stations and 38 Underground and light rail stations. Last but not least, 1.25 million Londoners live within the floodplain.

 GLA Flood RiskFlood Risk in Greater London Area (from UK Environment Agency )

Probability of water supplanting commuters in the London Underground neatly encapsulates the core property of flood control measures for London.  London's flood management system is first and foremost all about probability of occurrence of certain natural events. What are the chances that the river will rise beyond its constrained position within the Embankment and other barriers and what processes control those odds? Every physical embodiment of the flood control scheme springs from probabilities and their underlying drivers and all of the London flood control works are dedicated to improving the odds against river containment failure. 

A series of floods culminating in 1953's great North Sea Flood increasingly concentrated the attention of several successive British Governments on the task of quantifying and thus for the first time being able to engineer the risk of London's flooding. Proper statistics as well as obsessive measurement capabilities and (some will want to avert their eyes at this point) powerful modeling techniques were employed to aid in decisions controlling construction of and operational plans for state-of-the-art, fully rationalized flood control measures for the River Thames.

After all the numbers were crunched, it turned out that ordinarily mundane tides combine with weather systems to produce the most likely cause of a catastrophic flood in London. Upstream precipitation may make a bad situation worse but most of the trouble with the Thames is more probably going to arrive from downstream in the form of a storm surge coinciding with a high tide.  The worst possible scenario consists of the combination of heavy precipitation upstream with a spring tide and an unusually powerful storm system pushing water up into the Thames Estuary and it's that circumstance that might see Westminster Palace deluged again. Predictions of climate science indicate this worst-case drama will be more likely in the future.

Thames Tide and Surge 1953 Tide and Storm Surge (from Lundbak 1955 )

Enjoy some hours at The Anchor on Bankside drinking too much ale or imagine yourself as Samuel Pepys as he frequently embarked on small craft to cross or travel along the River Thames and it becomes transparently obvious that ordinary tides are a huge factor for engineers seeking to protect London. Broad swathes of beaches along the Embankment vanish as the tide balks the river running through London, the water rises along with what's floating on it and in a few hours time waves lap close to the top of the wall protecting London from the Thames. Where Pepys may have stepped directly into a boat from the Embankment, hours later he might face a long climb down and a trip across the strand.  Looking across the river from The Anchor at high tide one sees buildings apparently squatting almost at water level where previously they stood far above the surface.

Thames Tidal Range (photos courtesy of Dr. Amanda Bauer )

The infrastructure of the Embankment is arranged to cope with the ebb and flow of tides leaving a relatively small amount of freeboard to account for unusual excursions of the river level such as spring tides combined with high precipitation. Looking up and down the river it is not hard to understand why the Embankment is built to such a low level above mean high tide; there are miles and miles of riverbank to protect and building the Embankment to handle by itself all flooding scenarios is simply not practical or affordable.

The Thames Estuary is a classic shape for enhancing the effect of a storm surge, comprising as it does an enormous funnel with an increasingly shallow bottom in its upper, narrower reaches leading to London. Even if the estuary emptied into deep water it would be of concern, but the outer reaches of the estuary connect to an unfortunately shallow arrangement of bottom topography and shape of the North Sea, English Channel and Strait of Dover. Proximity to the North Atlantic dooms the whole arrangement to  frequent, powerful low pressure weather systems generating huge winds in this collection of shallow waters, potentially forcing an enormous surge up into the Thames Estuary to be concentrated at the top, just below London. Depending on the conjunction of tides and weather the Thames may swiftly bound upward far above spring tide levels regardless of the phase of the moon, producing the sort of destructive excursion noted by Pepys in 1663 with its easterly wind, or the 1953 event which took 300 lives in the estuary.  

Unlike gravitational tides, occurrences of storm surges are not deterministic, are not perfectly predictable with regard to arrival time and magnitude for centuries to come yet they interact with tides to pose a potentially lethal threat to London. While the exact timings and spacings of the arrival of storm surges are not predictable these features are nonetheless still amenable to statistical treatment and as well the effects of storms on water level can be bounded given valid observations about typical intensities and approach paths of storms to the Thames Estuary. Thus it's possible to produce reasonably useful numbers for engineering purposes when it comes to planning for robust defenses against storm surges.

All of the numerical underpinnings generated by scientists and engineers studying the behavior of the Thames, regional weather and tides are manifested in the physical world with a flood control system having as its centerpiece a remarkable feat of engineering  known as “The Thames Barrier.” This enormous  equipment can at least temporarily accomplish what King Cnut could not, arresting by main force the rise of the tide or a storm surge in the River Thames as it passes London. In conjunction with a number of lesser yet still absurdly large locks and gates leading to tributary channels this arrangement avoids the vast and essentially impossible amount of effort that would otherwise be required to fully constrain the River Thames during high water events using only embankments.

Thames Barrier
Thames Barrier (from UK Environment Agency )

Our conditions may turn out to be dynamic though that discovery may well unfold over the course of time. Like many of us Samuel Pepys was fond of stability, didn't like to be swerved from his habits and was perhaps a little too phlegmatic, but he remained sensitive to changing circumstances, rightly so. On the evening in 1666 when London began to burn, Pepys rose from bed briefly to view the glow on the horizon from his home but promptly went back to sleep. The next morning found him bustling between the King of England and the Mayor of London, transmitting instructions to the Mayor to hasten the pulling down of houses to check the fire, a strategy that was initially futile in part due to resistance from property owners. After Pepys' visit to The Anchor, recognition dawned that this inferno showed no sign of stopping and fairly shortly he found the fire arriving practically at his doorstep, a circumstance that seemed outside the range of possibility just hours before. Never one to give up, Pepys responded to changing conditions, sending his gold as well as his wife to a suburb and pondering what else what could be saved from his house. Having a garden and seeing the streets choked with goods, chattel and people late in leaving because of hesitation in the face of a constantly growing threat, Pepys swiftly arrived on a stratagem for preservation as well as an order of priorities for what must be saved. In his yard he buried his papers, his wine and his Parmesan cheese, neatly consistent with his reputation as a man with a rich intellectual life as well as a fondness for worldly pleasures.

Since the design and construction of the Thames Barrier, anthropogenic global warming has moved from a state of hypothesis to that of established, accepted theory, has become a factual challenge. As with Pepys' evolving problem with the Great Fire of London, probabilities of events leading to flooding of London are swiftly changing and the anticipated magnitudes of future floods are increasing even as our ability to recognize and anticipate what we may expect for London's future anniversaries with the River Thames improves.

Here's how the London Regional Flood Risk Appraisal of 2009 describes London's anticipation of  changes due to climate change:

  •  46. Climate Change will have a major impact on the tidal flooding threat. The rising sea level will steadily reduce the level of protection that defences offer. The predictions for how quickly sea level will rise vary considerably depending on the assumptions used about emissions and climate modelling. The TE2100 project has considered a range of climate change derived sea level rises from 0.9m (Defra 2006 Climate Change Scenario) to 4m (High++ Level where all conceivable sea level rise contributions up to 2100 occur).
  •  47. Up to 2030, i.e. to the end of the timeframe of the replacement London Plan, there are limited differences between predictions and existing flood risk management options can continue to provide appropriate risk management for tidal flooding. Beyond 2030 there is more variation in the projections. However it is clear that by starting to plan for these changes now, the ability to cope with more extreme situations will be improved. This is the aim of the London Plan policies.

Changes in probabilities and projected flood magnitudes necessarily lead to physical changes in protective infrastructure. As understanding of climate change has improved, so have the expectations of necessary changes to the Thames Barrier. Earlier estimated chances of overtopping of the current protection scheme have been superseded and even as designers have worked to take changes into account our prognostications become more clear and more challenging. Depending on how climate change unfolds, flood management schemes formerly estimated to offer 1:100 protection may drop in performance to 1:8 by 2050, with many becoming essentially worthless at 1:1 by 2080  (McRobie et al,  2005) . Faced with numbers like those, intermediate scenarios are not  a great source of comfort.

While there's a lag between the publication of scientific research results and their uptake by planners and engineers, the recent pace of enlightenment has been swift, leading to frequent reformulations of planning responses. In 2005 a Royal Society paper described how modifications to the barrier could help it to surmount an additional 1.2m of sea level rise on top of the amount anticipated to the original design, the additional amount allowing for the predictions of the then most recent IPCC synthesis with some overhead. These changes were described as allowing the barrier to afford protection for another 100 years past 2030. In 2007 concern about IPCC underestimation of sea level rise in part led to a revision of these plans, calling for total replacement of the structure in 2075 and beginning to acknowledge that uncertainties and undershoot in IPCC estimates of sea level rise were to be taken more seriously. 2010 finds plans centering on upgrading the London flood control system and the Thames Barrier to a level sufficient to handle increases of 2.7m because yet more recent signs coming from research point in that direction, making the aging and initially cautious IPCC assessment quite obsolete.

Sea level changes dominate much of the prognostication on London flood management but there's another outcome of climate change that must be dealt with in the circumstance of coastal areas proximate to the North Sea and that's storm frequency and intensity. These numbers of course help to control probabilities of overtopping. Research suggests that whatever improvements are made to the Thames Barrier and associated systems will be tested with increasing frequency and harshness ( Lowe 2001, Woth 2005 ).

Hints of climate change becoming visible have further increased activity on the part of planners. 2007's historically unprecedented rainfall deluge and subsequent flooding caused enormous damage over a large region southern England, affecting a sizable fraction of the population and unleashing a civil emergency response on a scale unseen since World War II. The flood  prompted national-level reassessment of flood hazards for all of the United Kingdom. The result was the governmental  Pitt Review, a comprehensive assessment of flood hazards and response strategies. The Pitt Review in turn found that 2004's governmental Foresight Future Flooding Report had already been superseded by fresh information with regard to climate change. In particular, possible five-fold losses of statistical protection are noteworthy:

  • There is a greater risk of extreme sea-level rise. Coastal flood risk remains one of the biggest risks the UK faces and, although the mean estimates of sea-level rise have not changed since 2004, larger rises of up to 1.6m, due to melting of large ice-sheets in Greenland and West Antarctica, are now a small, but real possibility by 2080. Communities living behind good coastal defences currently protecting them against a flood with a chance of occurrence of 1 in 100 each year could experience a drop in standard of protection by the end of the century to as low as 1 in 5 each year if we were to follow a business-as-usual flood management policy. 

In sum, dawning recognition of threats arising from climate change as well as what seems to be steadily increasing potential scope of those effects is forcing  continuing rearrangement of London's anticipated schedule of delivery and physical requirements for flood protection. Experience so far suggests that planned changes are lagging behind the developing climate problem, and may be in a state of flux for years to come.

London is responding in this way because regardless of discussions of motivation or broader geopolitical or commercial concerns they're confronted with an emerging set of facts pertaining to their specific mission. The planners in charge of protecting London cannot afford to mistake noise versus information, can't let themselves be swayed by peripheral chatter, cannot dismiss climate change as a threat by taking the wrong approach to uncertainties. These people correctly are incorporating changing information into their plans and their experience with changing requirements increasingly suggests that they take a pessimistic view of what portends for the future.

As with Samuel Pepys' political bent for stability, planners are taking a conservative approach, are ensuring that London is a rationally predictable place worthy of investment and that it may continue providing long term stability of the kind a nation's capital demands. It's hard to overstate the imperative to get the answer right in this case, “right” meaning to correctly make the best call against odds.  Planners working on revising London's flood control have got the fate of an enormous city, their country's physical government and by extension the fundamental health of their entire country in play.  The conservative approach to dealing with climate change from London's perspective is to pay close heed to things we today imagine are unlikely.

School Flood RiskSchools At Risk of Flooding (from London Region Flood Risk Appraisal )

In the final analysis, the price of failure in the case of planning London's flood control is astronomical while the price of improving odds for success positively pales in comparison. The cost of overdoing the response is essentially some extra shovel work, as with Pepys' protection of his valuables, nothing in comparison to making a mistake. That's why the wise course chosen by planners is to aim at overdoing the flood control scheme taking into account and going significantly beyond the already less-than-rosy predictions of the IPCC and other expert resources. They are not taking the expedient course of listening to naively optimistic stories about uncertainties making decisions impossible, or being encouraged to focus on the low side of uncertainty. The potential open-ended penalty for incorrectly listening to optimists far outweighs the better quantified, known price of the conservative approach to London flood control.

Instincts of these planners seem to be correct; as time goes by predictions and evidence concerning climate change are producing an increasingly alarming picture for London and similarly situated cities. Sea level change estimates by the IPCC are widely acknowledged to be on the low side. Multiple indicators of this ( Rahmstorf 2007, Rohling 2008 ) are leading designs to shift past 2007 IPCC sea level scenarios.

London flood management planning discussion has also taken note of increasing frequency of  Thames Barrier operation, consistent with expectations from climate change. Planners note that while no direct causal connection to climate change is possible this is indeed the general sort of statistical signal we'd expect to see as storm surges increase in frequency and size in keeping with predictions of storm response to climate change. Planners note that taken together with 2007's historically unprecedented summer flooding and other recent extreme precipitation events such as UK flooding in 2002 we have hints that  weather events are following climate predictions.

Thames Barrier Closure History Thames Barrier Closings (from UK Environment Agency )

It's intriguing to note that the Thames Barrier activation record is the subject of a familiar campaign of doubt. In keeping with so many other observations, some interests would have us believe that determining the motivating factors in any single actuation is impossible but  that's wrong; Thames Barrier actuation is a significant event triggered for specific reasons and generating attribution records ( London Flood Strategic Response Plan).

The issue of spinning data raises the matter of politics colliding with the requirements of people responsible for protecting lives and property. At the end of the day ideology and other motivations must comport with facts; engineers and technicians operating cities only have so much latitude to accommodate political abstractions before their job becomes impossible. People in charge of dealing with facts related to life safety and the preservation of investments must ignore talk that does not coincide with the best efforts of researchers.

The necessity to integrate emerging scientific knowledge with our lives and economies has produced a struggle for dominance in the political sphere. Enormous effort and money is being expended on shaping public policy response to climate change and as facts become more clear and the urgency of action increases, so does the frenetic pace of political influence on policymakers, as can be seen in the following illustration.

US LobbyistsU.S. Political Lobbyists Influencing Climate Change Legislation, 2003 vs. 2008 ( from Center for Public Integrity  )

This frantic effort to shape the outcome of policy is played out not only in such places as Westminster and Capitol Hill but also in the popular press and other venues where public opinion may be swayed. In accountable democracies public opinion after all has a significant effect on policy so it's not hard to understand why the battle for policy responses to climate change should spill out of the halls of government and into the public eye. Opinion sampling by social scientists using formal research methods can give us some hints as to the effects on public thinking on climate change as the fortunes of the policy war swing back and forth, as may be surmised from examples of scientifically conducted sampling. The following graphic shows how various centers of public  thought seem durable even as their exact proportions shift over time. 

From Global Warming’s Six Americas, June 2010

There are arguably three groups competing for dominance of public policy response to climate change and hence dictating the abilities of technicians to deal with facts. One group emphasizes scientific limitations to the point of complete disbelief or even imagines much of science bent to the purpose of a conspiracy and insists that essentially no changes are needed in our behavior or expectations of our environment, another highlights adaptation and believes we can do "business as usual" while largely weathering or innovating our way around or even enjoying whatever may come of climate change, while yet another believes the present course we're headed on is definitely untenable and will cost us dear in the fairly near future. The former two groups as they manifest themselves in political discourse seem related in some ways; both may fairly be said to harbor suspicions of "big government," increased taxation and the like. The two groups' proclivities coincide with the needs of some major commercial interests. Yet the second group can't rationalize its outlook with that of the first.

People arguing for adaptation as opposed to mitigation implicitly agree with those in favor of mitigation that climate change is a reality so there we find agreement but no common cause. Both groups will however find some concord with those responsible for dealing with disruption caused by climate change.

Arguments as to attribution may remain but for engineers and planners responsible for London attribution is not really relevant, water must be kept out of human space regardless. It's notable that of the thousands of pages of assessment and planning documents associated with future London flood management there is essentially no mention of anthropogenic causes for climate change, naturally so because cause has nothing to do with response when cause is outside of the control of planners. London turns out to have burned because the King's own baker was careless with fire but that did not figure into Pepys' attempts to bring the conflagration under control. 

Adaptation may seem like the softer, easier way to deal with climate change but adaptation should not be mistaken as a free pass to ignore climate change, as this example of London shows. Large amounts of money are being spent on adaptation, long-laid plans are being dislocated and London is going to continue expending significant resources on a forced adaptation process for decades to come. The city may well still be at greater risk in 100 years' time than it is today, still distracted with keeping its head above water. Adaptation is after all a gamble depending on optimism; as we can see from London's requirements and plans it is arguable that optimism in the face of tremendous risk is not a truly, usefully conservative characteristic.

There are also limits to adaptation of the style most of us probably imagine. All of the major investigations for planning of future flood control in the Greater London Area speak of a fall-back strategy envisioning making buildings and infrastructures more "resilient" against flooding, describing ways to minimize damage. They do this because it may not be financially or even physically feasible to provide effective flood control in the traditional style. Instead, residents of flood-affected areas may have to tolerate more frequent incursions of water. This is not an optimal outcome.

As described in Tidal Flood Risk in London Under Stabilisation Scenarios, here's how adaptation might play out, leaving us with the concerning word "viability" hanging in the air:

  • If the Thames Barrier can be operated, say, 10 times more frequently than it is at present it will be able to resist approximately 0.5m of relative sea level rise (roughly a century of sea level rise) before further modification of the upstream flood defences is required. Beyond that point the upstream walls throughout central London and westwards will have to be raised at roughly the same rate as sea level rise. This represents a significant commitment in the 22nd Century and beyond. Engineers suggest that feasible raising of the walls through central London may be limited to about 2m, in which case under more extreme sea level rise scenarios the limits to protecting London are reached in the 23rd Century. More sophisticated control of the Thames Barrier or a replacement could be used to extend the viability of the capital, and these options will need to be studied in the future.

Considering RiskConsidering Risk for Flood Management (from Pitt Review )

As a final note on adaptation's attractions and the uncertainties lumped in with adaptation, "business as usual" going forward isn't an option regardless of one's attitude to climate change, presuming one's metrics for success include medium to long term political and economic stability. Putting aside quibbles about what swiftly approaching decade will mark the onset of more serious and obvious logistical and geopolitical struggles over fossil fuels, increasing uncertainties over fuel supplies are already on the queue of challenges faced by governments and those responsible for the public welfare, steadily gaining urgency. This is particularly true in the case of liquid and gaseous hydrocarbons which under "BAU" face skyrocketing demand in the face of diminishing sources. Constraining energy costs and risks while promoting stability and prosperity are priorities those in favor of adaptation can't rationalize with procrastination over modernizing energy sources. While it's highly probable that substitution for the remarkable endowment of hydrocarbons we've relied on will be more expensive for some period of time to come, we can place more reliable boundaries on the prices of those substitutes than we can for diminishing supplies of fossil fuels. Creating known boundaries on uncertainty and risk is better than courting open-ended uncertainty and risk.

A better strategy would be to avoid knowingly driving up uncertainty and risk at all or at least sharply constrain them by making and following firm, useful plans for C02 emissions mitigation, the so-far failed cause of the third group of contenders for public policy dominance. Assuming they agree with the basics of radiative physics and at least to some extent with the concept of greenhouse gases as well as some fairly basic rules of economics, those keen on adaptation would do well to committing their lot with this last group, if keeping adaptation costs and risks lower is an important objective. As an example, if London planners were able to count on a future sea-level rise of just 1.3 meters, the current Thames Barrier could have been made to work for another perhaps another 150 years. Instead it will be replaced in a little over 60 years and data suggests the resulting protection level may be inferior to today. Examples of this kind will abound as the climate change scenario unfolds. As the late  U.S. Republican Senator Dirksen said, "A billion here, a billion there and pretty soon you're talking real money." Lose a few coastal cities and the quote might be paraphrased substituting trillions for billions.

Thames barrier upgrade probability

Probable year of next upgrade of the Thames tidal defences (from Tidal Flood Risk in London Under Stabilisation Scenarios

Returning once more to the late hero of our story, Samuel Pepys was not only a Member of Parliament and politician, he was also an early member and President of the Royal Society. As well, Pepys was a primordial technocrat, charged with shaping the development of the Royal Navy into what became known as  "the scientific Navy," a rational response to a public policy challenge both complex and crucial, intricate but with the future of a nation hinging on the outcome. In light of concerns over models, it's amusing to note that while Pepys had no practical experience of the sea, he educated himself on the construction and operation of ships by the use of models and gained a useful theoretical basis for improving the Royal Navy's fleet.  Pepys was a fellow interested in integrating scientific facts into policy and technical solutions to problems confronting government and was in the position to execute his ambitions, he was a one-man example of the continuum emerging in his time between scientific research and technical outcomes of government and public policy.

The world has become too complex for a single person such as Pepys to wear so many important hats. For better of worse, our governments and political systems are not so coherent as they were in Pepys' day. Today it's worth asking, what if the political influence of those in the "it's not happening camp" who unlike Pepys are unprepared to remain in the world of emerging facts should invade and control the world of those those charged with protecting the public from London's flooding? Should unfounded opinions of a political class divorced from science dictate the options of engineers and technicians responsible for dealing with factual reality? Can we afford to let that happen? It's intriguing to note a general pattern with regard to this possibility, a feature that might confuse Pepys. As we move upward through the hierarchy of government, vacillation and hesitation seem to increase. Greater London is responding crisply to emerging facts. In the United States at the national level debate rages about whether the Environmental Protection Agency's decision to treat C02 as an emerging threat despite factual suggestions that it should do so. Globally, at the transnational level of government, paralysis rules the day. Why this is so is a matter of debate but upper governmental echelons might look to their underlings as well as historical figures such as Samuel Pepys for cues to sensible behavior. 

Concisely conveying the story of such a long, rich yet bumpy and increasingly fractious relationship as London has had with the Thames is difficult but at least London's is a story with the possibility of a happy ending. Though London's issue with storm surges is notably bad, in many ways the city is far better off than many other major cities situated so near and low to the ocean as to be almost in it. London is a geographically defensible city, London can afford to defend itself, London is armed with a competent civil service rich with technical and administrative talent, and finally motivation to defend London is very strong because London is both the capital of a country and is the home of a stellar array of influential people and businesses, a constellation of Pepys-like influentials. Leaving aside the unfortunate matter of the estuarine funnel attached to the ocean-weather dynamic duo just offshore, London is one of the rosier scenarios  for the saving of low-lying cities attached to tidal waters, leaving the question of what we're prepared to accept in worse situations,  Does anybody who has driven through the city and witnessed ocean-going ships passing far overhead seriously believe New Orleans is not a lost cause if sea level has increased by 2 meters, or that it can be made as safe as it is today when the ocean has risen by 1 meter?

0 0

Bookmark and Share Printable Version  |  Link to this page

Comments

Prev  1  2  

Comments 51 to 79 out of 79:

  1. I think you and I share a problem w/biting our tongues, GC.

    Often said to cab drivers, random guests at parties, etc.: "Don't get me started." They don't realize the gravity of my advice... :-)
    0 0
  2. Doug,
    Your link at 16 was an interesting read. Unfortunately it seems that the real pain will not be for several decades. If that is the case and people wait for their thousand cuts to start before taking action it may be a late start. While this was more up to date than the Tampa plan, they still estimate only a maximum of 0.65 meters by 2080. IPCC estimates for the next report will likely be up to 2 meters by 2100, more than double 0.65 m by 2080.

    GC,
    I have not seen the Dutch dunes, although I believe you that they are impressive. I do not think that Florida can copy them. The area to be protected is too big. Are you going to build the levies on our tourist beaches? Even if you were able to protect the cities, how would you protect the roads and get fresh water to drink? Holland has water run in from higher land while Florida gets salt intrusion now. There are only 6 or 8 million people threatened in Florida, we can all move to South Dakota.
    0 0
  3. Doug, that’s quite a scary diatribe you’ve put together there so will take a bit of reading. Never mind, I’ll try to make the time to go through it in detail. On a quick scan I was immediately reminded of a similar scare story about climate change and the risk of Westminster being drowned – Mark Lynas’s science fiction booklet “Six Degrees: Our Future on a Hotter Planet” (Note 1). That has as its front cover a picture of London almost underwater – enough to frighten the most sceptical member of the general public into accepting without question The (significant human-made global climate change) Hypothesis.

    Well, not quite. I was very concerned about my grand-childrens’ future after reading the Times on Sunday’s 11th March 2007 review of Six Degrees so I went to the library and took out the book. It is full of misrepresentations which I’ve pointed out to Mark but he was never prepared to respond on them. I wonder if you will adopt the same approach if I find any in your missive.

    Lets make a start.

    1) “Since the design and construction of the Thames Barrier, anthropogenic global warming has moved from a state of hypothesis to that of established, accepted theory, has become a factual challenge”. No Doug, The Hypothesis remains a hypothesis.

    2) I can find no evidence to support the claim “historically unprecedented rainfall deluge” in the statement “ .. 2007's .. rainfall deluge and subsequent flooding caused enormous damage over a large region southern England .. ”. On the contrary, it seems that The Great Flood 1968 (Note 2) may have been worse and what about 1953, 1928, 1894, 1891, 1877, 1875, 1872 and 1869?. (I’m sure there are more). Perhaps you’d like to provide a link to the evidence that supports your statement about 2007.

    Another thing that strikes me about your diatribe – it makes the assumption that the small amount of global warming that we may have experienced over the past 150 years is going to continue and have a significant impact upon the extent of flooding in the SE of England. As I understand it this is only a hypothesis based upon the projections of computer models that have never been validated, but that’s for a different thread.

    Sorry, must dash as the boss is calling.

    NOTES:
    1) see http://www.amazon.co.uk/gp/product/B002RI9F0E/ref=pd_lpo_k2_dp_sr_2?pf_rd_p=103612307&pf_rd_s=lpo-top-stripe&pf_rd_t=201&pf_rd_i=0007209045&pf_rd_m=A3P5ROKL5A1OLE&pf_rd_r=114R8ETZ1PW2FS220J2B
    2) see http://en.wikipedia.org/wiki/Great_Flood_of_1968

    Best regards, Pete Ridley
    0 0
  4. Pete Ridley wrote : "The Hypothesis remains a hypothesis."


    If you can't even recognise the difference between a theory and a hypothesis, I respectfully suggest that you are immune from reason and will not accept facts and evidence that do not conform to whatever system of beliefs informs your world-view.

    Theory - a supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained

    Hypothesis - a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation

    To help you see the difference, you will need to read more on this site, specifically :

    More evidence than you can shake a hockey-stick at

    10 Indicators of a Human Fingerprint on Climate Change

    10 Key Climate Indicators Point to the same finding - Global Warming is unmistakable

    Empirical Evidence for Global Warming

    Now, if you can disprove any of that, or show that it is 'limited evidence', then you will be famous and will have proven that the AGW theory is, in fact, a hypothesis. If you can't (which you can't), you should start accepting the facts as they exist in the real world and move on to arguing about something which you can defend with rational arguments, rather than relying on 'comfort-phrases' which satisfy some need you have to deny what is happening around you.

    And, just to keep this on-topic, if you had read the Pitt Review (which was linked to above), you would have read this :

    The rainfall during June and July 2007
    was unprecedented. The severe flooding which
    followed came after the wettest ever May to
    July period since national records began in
    1766.


    And this :

    It was the most serious inland flood since 1947
    (MISSED FROM YOUR LIST, SOMEHOW)

    Have a look at the Review.
    0 0
  5. Pete Ridley and I are much alike. Not much to say but we're absolutely the cat's pajamas when it comes to finding long-winded ways to say it.

    W/regard to historical floods and the like Pete, if you disagree with the folks keeping track of such things you'll need to complain to them. If you follow the various links in the article you'll find where to lodge your complaints. For getting sorted out on hypothesis versus theory concerning AGW, check with the U.S National Academies of Sciences; the "factual" and "theoretical" basis of AGW is from them, as you'll discover if you follow the link.

    If ignoring all this stuff allows you to enjoy your grandchildren more, I certainly don't want to get in the way of that.
    0 0
  6. JMurphy, thanks for providing others with those excellent definitions of “theory” and “hypothesis”. I always try to choose my words very carefully and the definition of “hypothesis” fits perfectly The (significant human-made global climate change) Hypothesis i.e. “a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation”. Of course, those investigations into those significan uncertainties about global climate processes and drivers continue across the globe, at enormous but necessary expense. There is so much that the scientists need to learn. Thanks again.

    Regarding the links that you provided to what you appear to (mistakenly) regard as evidence sufficient to change the status of The Hypothesis to that of a theory, these simply support the argument that during the past 150 years there appears to have been a small amount of global warming, some of which has been contributed to by humans. Few sceptics would seriously dispute this. What they do not provide evidence of is that such warming will continue indefinitely to the detriment of humankind. BTW, I do not believe that I have ever sought to disprove the theory of AGW. If you can find me suggesting that anywhere then please let me know and I’ll correct it.

    Thanks for providing that help that I asked for about evidence to support the claim “historically unprecedented rainfall deluge”. Maybe the Pit Review includes such evidence rather than simply making the claim which you quoted. As I indicated, I’ll need to make some time to look more closely at what has been claimed in Doug’s diatribe. There is a big difference between “unprecedented” and “unprecedented since records began” and I hinted at a similar error in one of Doug’s comments on the “Confidence on Climate Models” thread (see his mini-diatribe at comment #93 and my comment #97).

    Doug, there’s a time and a place for everything. Don’t worry. I’ll enjoy my grandchildren and look more closely at the scare stories about London sinking under the seas as and when I choose until I pass on to the hopefully perpetually warm and comfortable life to follow this one (if what I was told during my childhood is to be believed).

    Best regards, Pete Ridley
    0 0
  7. Pete, in the interest of being fully informed regarding your personal opinion of AGW being a hypothesis as opposed to where the scientific community today stands, I encourage you to read this NAS report, which I cited in the article. It's not possible to provide redundant and lengthy supporting material in everything written about this topic, but down here we have a little more room so I'll just quote briefly to address your concerns:

    Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities.

    It's worth stopping and thinking a moment to consider this juxtaposition, a very simple one: your opinion versus the NAS. Again I encourage you to read more, that's all I can do.
    0 0
  8. Pete Ridley wrote : "As I indicated, I’ll need to make some time to look more closely at what has been claimed in Doug’s diatribe."


    You just get better at posting more lack of substance. You accuse someone of composing a bitter, abusive denunciation, attack, or criticism (otherwise known as a diatribe - but against what or whom is still unclear), even though you admit you haven't had "time to look more closely at what has been claimed" ! Are you just permanently set on 'argue the opposite', no matter how little you know' ?

    And yet...you haven't had time to look closely to see whether the 'diatribe' was, in fact, based on facts, BUT have been able to find a little time to assert (against, don't forget, something you haven't had time to check up on) that "[o]n the contrary, it seems that The Great Flood 1968 (Note 2) may have been worse and what about 1953, 1928, 1894, 1891, 1877, 1875, 1872 and 1869?. (I’m sure there are more)."
    So, you are asserting something that you don't know to be true (the years you mention MIGHT have had greater floods, especially the year 1968 whose title of 'The Great Flood' may have led you to believe it MUST have been a biggy) against something that you haven't actually checked !

    The title of this thread is called "Grappling with Change : London and the River Thames" : that is nothing compared with grappling with so-called skepticism and trying to work out which argument is honest and credible, and which is made up as they are typing.
    0 0
  9. Pete, did you notice in the above quote (57) the NAS says that AGW has gone beyond the status of well supported theory and should be considered an observed fact. You are a little behind saying it is only a hypothesis. Maybe you can update and say it is only a theory, not a fact.

    The predictions of change that were made in the 70's and 80's are happening faster than predicted (ice melt, sea level rise, extreme precipitation, fires, ocean acidity). What makes you so optimistic that the future will be better than forecast?
    0 0
  10. Doug, may I start by apologising for accusing you of writing a diatribe. I was reacting to what actually thoughtfull said on the “Confidence in climate forecasts” thread. His comment was between two of yours and I associated the word with you – my mistake.

    Regarding what you call my “personal opinion of AGW being a hypothesis ”, I invite you to read my comment 56, 2nd paragraph. I cannot understand why you consider my opinion about The (significant human-made global climate change) Hypothesis conflicts with what you quoted from the NAS paper. I have searched through all of my posts to this blog and can find nowhere that I have referred to AGW as a hypothesis. I believe that I have used the term on only four occasions. That was thrice on “How reliable are the Climate models” (comments #207 on 26th July @ 19:52 & #217 on 28th July @ 02:34 – quoting Phil Scaddenthen, #219 on 28th July @ 06:46 – quoting JMurphy) then on the “Why I care “ thread on 8th August @18:18. None should give you the impression that you have. On the contrary the last two comments should make clear to anyone what I see as being The Hypothesis. I would appreciate you pointing out anywhere that I have said or suggested that Anthropogenic Global Warming (AGW) is a hypothesis.

    JMurphy, would it be unfair of me to accuse you of bias? I didn’t notice you huffing and puffing at actually thoughtfull on the “Confidence in climate forecasts” thread when he used the word “diatribe” in his comment to me on 9th August @ 07:00.

    Michael Sweet, it appears that you make the same mistaken interpretation of what I say as do others here. Could this be deliberate I ask myself.

    Best regard, Pete Ridley
    0 0
  11. Pete,
    I am sorry if I misinterpreted your post. It seems to me that you are splitting hairs in your statements and complaining when others do not agree with your split. When I read the NAS statement it seems clear that they mean "The (significant human-made global climate change) Hypothesis" has been measured as a fact. They clearly state that the scientific consensus is that severe consequences will result from BAU. They cite multiple lines of evidence. Where do you find room in the NAS statement to justify your claim that the measured changes are not significant?

    You did not respond to my list of predictions that have come to pass (theories predict things that come to pass). Sea level rise, sea ice loss and ice sheet loss exceed many of the model predictions. I think these are "significant human-made global climate change". Why do you think 2 meters of sea level rise (the current high end, raised from less than 1 meter only 3 years ago) will not be a problem for your grandchildren? The planning documents Doug quoted suggest that over 2 meters it will be too expensive to defend London. It will certainly be too expensive to defend Florida, where I live.
    0 0
  12. I have searched through all of my posts to this blog and can find nowhere that I have referred to AGW as a hypothesis.

    Pete, I think we're working through the hypothesis issue at your suggestion, or that is to say because of what implicitly appears to be a misunderstanding on your part judging by your own words.

    In your own words (many times):

    The (significant human-made global climate change) Hypothesis

    It's not surprising some folks believe you're assigning AGW to the status of "hypothesis."

    On the other hand, the NAS says:

    Some scientific conclusions or theories have been so thoroughly examined and tested, and supported by so many independent observations and results, that their likelihood of subsequently being found to be wrong is vanishingly small. Such conclusions and theories are then regarded as settled facts. This is the case for the conclusions that the Earth system is warming and that much of this warming is very likely due to human activities.

    Comparing your words to the NAS it's reasonable to form the impression your assessment is at variance w/the scientific community.

    Now I suspect you're going to mention "significant" as the issue in play here. I suggest you turn to Part II of the NAS report and arm yourself with information before relying on significance of human contributions to climate change as a reason to dismiss concern over this issue. Overall Part II is an excellent summary of our understanding of this topic while beginning at page 158 you can read about the significance of human impacts on climate behavior. Be sure also to see figure 6.4.
    0 0
  13. Michael I don’t see that we are splitting hairs on the fundamental issue. This is whether or not emissions of CO2 into the atmosphere arising from our use of fossil fuels has made, is making or will make any significant contribution to past, present or future global climates (or weather events). Discussing whether or not it is correct to refer to opinions on this issue as hypothesis, theory or even law is pure semantics so let us stop wasting time on it. I’m not impressed by the numbers argument (scientific consensus) in supporting conjecture, only by what I recognise as hard evidence and am always suspicious of statistical manipulations and people with political motives.

    Your “list of predictions” includes such speculation and the first one, “sea level rise” is something that I have been involved in recently as I have been reviewing a draft book on the subject of sea level change being written by a couple who are not scientists. They, like you, obviously QUOTE: .. think these are "significant human-made global climate change" .. UNQUOTE but this does not make it a fact. May I suggest that you take a look at the 2009 article “SOUTH PACIFIC SEA LEVEL: A REASSESSMENT” at the New Zealand Climate Science Coallition site (Note 1). I particularly like that column “Years with zero trend” in Section 3 Conclusion.

    Doug, I have had quick look at the NAS report and so far have found nothing that I haven’t seen before, either in AR4 or the numerous papers and articles that I have read during the past 3 years. I may be able to make time for a further read but looking at some of the over 200 references mentioned there to “uncertainties” and “estimates” about those horrendously complex global climate processes and drivers gives me a hint that I’ll be wasting valuable time. I was disappointed to see virtually nothing about assumptions made.

    NOTES:
    1) see http://nzclimatescience.net/images/PDFs/spsl3.pdf

    Best regards, Pete Ridley
    0 0
  14. Pete:
    You cited a non-peer reviewed article by a single author dating back to only 1993 and covering only 12 islands as more authoritative than the US National Academy of Sciences? The entire paper consists of eyeballing data, no analysis is performed.

    If this is what convinces you have a good day. The NAS study Doug linked has real sea level data on page 156.
    0 0
  15. Typo: should be page 186 in the NAS report.
    0 0
  16. Michael, I don’t think that the Australian Government would be very impressed with your derisive “ .. dating back to only 1993 and covering only 12 islands .. ” comment about their The South Pacific Sea Level and Climate Monitoring Project (Note 1). You seem to be suggesting that the coverage they have established for that part of the globe will provide inadequate data. The Monitoring Network (Note 2) comprises:

    “- Sea Level and Meteorological Monitoring Stations. The current network of 12 robust and low maintenance Sea level Fine Resolution Acoustic Measuring Equipment (SEAFRAME) monitoring stations is providing excellent service. All parameters having an effect on sea level (wind, air and sea temperatures, atmospheric pressure) are being sampled at one second intervals. Sea level readings are taken and averaged over three minutes and meteorological data is collected and averaged for 2 minutes at the hour.

    - CGPS Monitoring Stations. The Continuous Global Positioning System (CGPS) network monitors vertical movement in the earth's crust, such as subsidence or tectonic shifts, at the SEAFRAME tide gauges and adjacent land. Sea level data can then be adjusted to compensate for the earth's movement to within a millimeter, enabling the absolute sea level to be determined.”

    Perhaps you’d like to show how the monitoring network used by Church & White (2006), Holate & Woodworth (2004) and Leuliette et al. (2004) to produce the data used in the NAS graph compares.

    You say that “The NAS study .. has real sea level data on page 168” but what I see on that page is a graph that purports to represent changes in annual mean sea level as determined by tide gauges and satellite altimeters, along with rate of sea level rise estimates. How reliable are those estimates, arrived at following statistical manipulations undisclosed on that page?

    Far more important to our discussion is the statement just above that graph “Distinguishing the effects of natural climate variability from human-caused warming is one of the challenges of understanding the details of past sea level and anticipating its future course”.

    You might also consider Dr. Roy Spencer’s “My Global Warming Skepticism, for Dummies” comment (Note 3) “ .. to the extent that warming occurs, sea levels can be expected to also rise to some extent. The rise is partly due to thermal expansion of the water, and partly due to melting or shedding of land-locked ice (the Greenland and Antarctic ice sheets, and glaciers). But this says nothing about whether or not humans are the cause of that warming. Since there is evidence that glacier retreat and sea level rise started well before humans can be blamed, causation is — once again — a major source of uncertainty” – “hear hear” to that.. You may like to read his book “The Great Global Warming Blunder: How Mother Nature Fooled The World's Top Climate Scientists”.

    NOTES:
    1) see http://www.bom.gov.au/pacificsealevel/
    2) see http://www.bom.gov.au/pacificsealevel/technologies.shtml
    3) see http://www.drroyspencer.com/my-global-warming-skepticism-for-dummies/

    Best regards, Pete Ridley
    0 0
  17. Pete,
    The study you referenced in 63 was not a scientific evaluation of the data the Australian gorvenment collected. It was a denier eyeballing the data and concluding the Australians were wrong when they measured the sea level rising. I have no problem with the Australain data. Why don't you use the scientists evaluation of their own data here instead of some denier pap?

    If you have a problem with the NAS data you need to read their references. In a summary report they do not have enough space to answer the detailed questions you are asking. People are expected to learn the background on their own, some of us have not done our homework yet. If you have trouble with this summary, you should make a better effort to find a summary you can understand, not discard the report. This web site has a number of basic summaries that you could start with.

    The scientific position on causation of sea level rise is discussed in the NAS report. Obviously, if humans cause the warming and warming causes sea level rise, then humans caused sea level rise. Roy Spencer is one of the 3% of scientists who disagree with the consensus. Why should I listen to the fringe crowd, especially someone like Spencer who has been shown to be wrong any number of times in the past? In any case, recently he has conceded that his data now matches the surface record that he criticized in the past. Other scientists corrected his mistakes.
    0 0
  18. Pete Ridley at 00:26 AM on 11 August, 2010

    All of the recent global sea level analyses use similar high resolution tide gauge data, as well as GPS/satellite altimetry as in the South Pacific Project. There is a global integrated sea level monitoring system and the South Pacific stations are part of it. In my view you have been extremely selective in your choice of references on sea level. Have a look at this short article on sea level rise where I cite the main recent references available in early 2010, and incidentally provide some visual clues as to why sea level rise in the South Pacific is not representative of sea level rise globally, notwithstanding that a 15 year period is less likely to give statistically significant trends when analysing individual stations (this seems to be a tactic often used by skeptics) as has been done in your reference. I could cite you many individual tide stations where sea level has actually fallen over the entire satellite recording period, but this does not change the global result. I suggest you gain much more knowledge of climate data and recent scientific research, and then balance this against the minority views of Spencer.
    0 0
  19. Let's see. In these two comments (first, second) Pete Ridley suggests that we should use data from a network of 12 GPS stations in the South Pacific to look at sea level rise. He also dismisses global studies of sea level based on the combination of satellite altimetry and gauge data.

    The satellite record shows a global trend of around +3.3 mm/year over the past two decades (thanks, Peter Hogarth!)

    The South Pacific GPS network that Pete Ridley refers to shows individual trends ranging from +3.2 to +8.6 mm/year (ignoring one outlier of +16.8 mm/year). The mean is +5.4 mm/year and the median is +4.9 mm/year.

    So, the network of stations that Pete Ridley was recommending actually shows a rate of rise that's about 50% greater than the global mean from the satellite record. However, as noted in the annual reports on the South Pacific GPS project, sea level in that region is known to be rising faster than the global average, and this regional difference shows up in the altimetry data as well. Taking this regional difference into account, their annual reports conclude that:

    The net sea level trends are positive at all sites, which indicates sea level in the region has risen over the duration of the project. The sea level rise is not geographically uniform but varies spatially in broad agreement with observations taken by satellite altimeters over a similar timeframe.
    [...]
    The sea level trends from SEAFRAME stations are mostly higher than the global average rate, but this is consistent with higher rates in the southwest Pacific measured by satellite altimeters


    So, if Pete Ridley likes the South Pacific CGPS project, he must also approve of the global satellite-based sea level record, since the two data sets are mutually consistent.

    Surely Mr Ridley isn't arguing that the satellite altimeters are accurate over the South Pacific but inaccurate over the rest of the ocean.....
    0 0
  20. Not to prematurely consign my article to the dustbin of history but the topic of accuracy of sea level measurements is already treated here on SkS and includes some helpful discussion around confusion concerning sea level measurement and the like. Rather than reenacting that history here, perhaps it would be better to contribute to existing threads.

    "How much is sea level rising" has a well developed discussion on measurement uncertainties.

    There's also "How much will sea levels rise in the 21st Century?", devoid of discussion but with a writeup by John Cook including data to work from, probably more germane to the exact discussion that has arisen here.
    0 0
    Moderator Response: Excellent suggestion. This is one of those cases in which an original post on a broad topic legitimizes comments on all those topics, but at some point the comments get so detailed that continuation on that original thread no longer is appropriate. Everyone is welcome to post a comment on this thread, announcing that they have posted a comment on a more specialized, relevant thread. I suggest you even paste a link to your comment on that other thread. (Right click on the time-date stamp of your comment on the other thread.)
  21. Pete if you don't mind I'll refer to something you said in relation to Ned's recent post, as support for a general observation.

    Pete said:

    I may be able to make time for a further read but looking at some of the over 200 references mentioned there to “uncertainties” and “estimates” about those horrendously complex global climate processes and drivers gives me a hint that I’ll be wasting valuable time. I was disappointed to see virtually nothing about assumptions made.

    Looking beyond the immediate topic of sea level rise, Ned's remark exactly illustrates how Pete's reasoning about "wasting time" looking at citations is incorrect, and how his remark about seeing "virtually nothing about assumptions made" is not actually right. We have to look at all the information made available to us if we want to avoid ambiguities leading to fallacious conclusions. If we choose not to or cannot find the time to do so, that's not an argument against the worth of what we personally don't know.

    Personalizing this, for the article above I made a best effort to summarize what I was able to find from a variety of authoritative sources on London and floods. If I missed something in my research leading to errors in my little essay, that doesn't mean I'm right and the rest of the world is wrong, it simply means I'm ignorant of certain things. Ignorance is universal and thus permissible but we should deal with ignorance in a conservative way; I should not claim that because I don't know something nobody else does, or that my perspective is correct when I have cause to believe I don't have a complete grasp of my topic. I should be mindful of accidentally conveying and promoting misperceptions springing from my ignorance.
    0 0
  22. doug_bostrom at 04:22 AM on 11 August, 2010

    Agreed.
    0 0
  23. 30.doug_bostrom at 11:45 AM on 5 August, 2010

    Doug it's a little weak to suggest the data I presented is just an aspect of a psycological problem I have.

    There is no significant trend for storminess in the North Sea that I can find published.

    The list of Thames barrier closures shows a downward trend in the surge and High Water Level readings during closure events suggesting the barrier is being closed for less severe events.

    Ocean levels have risen how much in the last 3 decades? 10cm?

    There is no justification to suggest the very large increase in barrier closures has anything to do with real changes in climate.

    Deal with the points rather than my mental state.
    0 0
  24. I'm not the person to deal with your points, HR, I'm the wrong person to challenge. You're in disagreement with experts having more knowledge of this topic than either of us.

    What I can surmise based on what I've read of our processes of cognition is that your disagreement with people knowing more of the topic of operating the Thames Barrier than the both of us suggests you're unwilling to confront information that makes you uncomfortable. I can't think of any other explanation.

    By the way, you're by no means unique or even at fault for having a hard time dealing with risk. As far as researchers can tell so far it's a universal trait of humans.
    0 0
  25. Further to HR's remarks, I see that it's actually quite easy to find publications indicating some changes in storm behavior and frequency in the North Atlantic. I should not so easily conclude that I can't contribute a little further information here.

    Increasing destructiveness of tropical cyclones over the past 30 years

    A shift of the NAO and increasing storm track activity over Europe due to anthropogenic greenhouse gas forcing

    Heightened tropical cyclone activity in the North Atlantic: natural variability or
    climate trend?


    Trends in Northern Hemisphere Surface Cyclone Frequency and Intensity

    As the London folks noted, this information is in keeping w/predictions. As they also noted, while no particular storm can be linked to climate forcing it would not be prudent to ignore an emerging pattern of observed evidence of a predicted trend.

    HR, this exercise leads me to suggest you ask yourself, "Why did I talk about sea level change over the past 30 years when our topic is about sea level rise over the next 100+ years? Why am I trying so hard to ignore what's in front of me?"
    0 0
  26. Doug, getting back to your article, in which you address a long-standing battle between nature and humans – flooding - let’s try to resolve some points of disagreement (which may arise from the interpretation of words rather differences of opinion.

    You say in your article “It's notable that of the thousands of pages of assessment and planning documents associated with future London flood management there is essentially no mention of anthropogenic causes for climate change, naturally so because cause has nothing to do with response when cause is outside of the control of planners”. Of course there is another way to explain that lack of any mention of humans causing climate change. Perhaps the authors saw no convincing evidence that any such changes were at all significant.

    One thing that puzzles me is that London was established as a major urban area around AD 70 and has grown rapidly since (Note 1) with the population peaking in the 1940s. During those 2000 years we are led to believe that global mean temperature rose to a peak about AD 1300, fell to a low about AD1600 and has been rising since. In 1990 the IPCC was suggesting that the medieval period was hotter than in 1975 (Note 2) - but there is considerable debate about the extent and rate of increase occurring presently.

    Despite those higher medieval temperatures it was not until the damaging floods in 1928 and 1953 that consideration was given to the need for a “Thames Barrier” and that was not for protection from unusual downpours but “.. to prevent London from being flooded by exceptionally high tides and storm surges moving up from the sea” (Note 3). The Institute of Historical Research (Note 4) says “The lands bordering the tidal river Thames and the Thames Estuary have historically been highly vulnerable to marine flooding. The most severe of these floods derive from North Sea storm surges, when wind and tide combine to drive huge quantities of water against the coast, .. ”. This is substantiated by the Environmental Agency (Note 5).

    The London Regional Flood Risk Appraisal – October 2009 (Note 6) talks about “ .. responding to potential increases in flood risk from urban development, land use change, and climate change .. ”. They put climate change at the end of the list, perhaps because of the enormous uncertainty about what changes will occur. The extent to which global mean temperatures will rise, fall or remain the same is unknown and climate change can only be speculated about.

    There are apparently two causes of rising water levels in that area:
    1) post glacial tilting of the UK, up in the N & W and down in the S & E,
    2) rise in the high water level (2mm/year).
    Although the last ice age is long gone the effects of the weight of all that extra ice are still with us, including the restoration of equilibrium to the land. It is suggested (Note 7) that “Today, typical uplift rates are of the order of 1 cm/year or less” which suggests that sink rates are of the same order. I wonder how much of the mean sea level change (3mm/yr approx?) estimated using tide gauge measurements results from this sinking rather than from any global warming. Can anyone link to a study covering this?

    NOTES:
    1) see http://en.wikipedia.org/wiki/History_of_London
    2) see http://www.uoguelph.ca/~rmckitri/research/NRCreport.pdf
    3) see http://en.wikipedia.org/wiki/Thames_Barrier
    4) see http://www.history.ac.uk/projects/tidal-thames
    5) see http://www.environment-agency.gov.uk/homeandleisure/floods/117047.aspx
    6) see http://static.london.gov.uk/mayor/strategies/sds/docs/regional-flood-risk09.pdf
    7) see http://en.wikipedia.org/wiki/Post-glacial_rebound

    Best regards, Pete Ridley
    0 0
  27. Pete, I don't see any points of disagreement to resolve with you, only some repetitions of things I mentioned in my article and from which some folks may derive comfort, and some speculations on your part.

    As to your question about the contribution of isostatic adjustment to local sea level rise, earlier in this thread of comments that question came up.

    Answer:
    Indeed the whole southern coast of England is sinking dorlomin. The rate varies by location; near London it's dropping at a pretty good clip of 0.5mm/yr.
    0 0
  28. doug_bostrom,
    I seldom post on WUWT but recently they had a thread on using submarine cables for making scientific measurements. I could not resist adding a little bit of history relating to the river Thames and a 29 acre factory located several meters below the high water mark along its tidal reaches:
    http://wattsupwiththat.com/2010/08/13/old-telco-cables-wanted-for-climate-research/#comment-457360
    0 0
  29. That's interesting, GC. Some time ago I read that a number of defunct submarine coaxial cables were being volunteered by owners for use w/a seismometer network and some other data collection tasks. One was to be attached (if I remember correctly) to a Japanese instrument platform to be powered by a saltwater battery.

    Regarding subsurface factories, reminds me of the old Pete Seeger tune.
    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

THE ESCALATOR

(free to republish)


© Copyright 2019 John Cook
Home | Links | Translations | About Us | Privacy | Contact Us