BANNED - Sea Level Rise

"Let all men know how empty and worthless is the power of kings. For there is none worthy of the name but God, whom heaven, earth and sea obey."

Does everyone know the legend of Canute the Great, Viking king of Denmark, England, and Norway around 1000 AD? The man who, in an attempt to dispel the myth that he was all-powerful (as well as showing piety), placed his throne on the shore and ordered the sea level to not rise up to him (BBC 2011). When it ignored his order, as he had wanted, his point was made and others could see the limitations of humans.

Beach protection at Outer Banks, North Carolina - Source: CoastalCare.org

Why then do some lawmakers in several American states believe that they can tell the oceans to stop rising? Do they feel, as Canute did, that they are receiving too much praise and flattery? Or do they simply believe that they can control the oceans?

Seemingly a wave of sea level denial has spread across the American South. If your state is at risk of sea level rise you might want to avoid what legislators and state officials in Texas, Virginia, and North Carolina have proposed.

Efforts to legislate away the threat and reality of sea level rise began in Texas last year. The Texas Commission on Environmental Quality commissioned a scientific study of a section of Texas’ coastline. The problem was that the Commission didn’t approve of references to sea level rise and so had them removed from the report (Grimm 2012). Incredibly, author of the study John Anderson, who has like his fellow authors asked to have his name removed from the paper, said that “they actually omitted whole sentences that mentioned sea level rise.”

Similarly, in June a study looking at the effects of climate change on Virginia’s coastline was only approved by its General Assembly after references to ‘sea level rise’ and ‘climate change’ had been removed from the $50,000 report (Leber 2012). Instead, it used approved terms such as ‘recurrent flooding’. What reason could be given for this? Well, the one given by the Republican State Delegate Chris Stolle is that the omitted terms would simply politicise the report as ‘sea level rise is a left-wing term”.

It is not the case that Virginia has escaped the impact of rising sea levels though. Norfolk, Virginia spends around $6 million/year improving drainage as well as elevating housing and roads (BBC 2012). Additionally, during storms 5-10% of the city receives heavy flooding. Responses to these problems, and repair of the naval base, surprisingly make no mention of climate change or sea level rise.

Seb Hall, a follower of the blog, recently brought the video clip below to my attention. The news report takes a comedic slant to discuss the attempts by east coast legislators to ban the phrase ‘sea level rise’ and by doing so in my opinion, highlight how ludicrous the measures seem to be.

                              

North Carolina is also mentioned and there is good reason for this. In June, policy makers that didn’t like the impact that predictions of a 1 metre rise in sea level would have on the state’s business interests wrote a law to control how it is measured. The bill says that:

“These rates shall only be determined using historical data, and these data shall be limited to the time period following the year 1900. Rates of seas-level rise may be extrapolated linearly. …”

You may find it amusing to read Scott Huler’s blog in which he rants about these measures. I have picked out one of my favourite sections for you to read:

“North Carolina legislators have decided that the way to make exponential increases in sea level rise – caused by those inconvenient feedback loops we keep hearing about from scientists – go away is to make it against the law to extrapolate exponential; we can only extrapolate along a line predicted by previous sea level rises.

Which, yes, is exactly like saying, do not predict tomorrow’s weather based on radar images of a hurricane swirling offshore, moving west towards us with 60-mph winds and ten inches of rain. Predict the weather based on the last two weeks of fair weather with gentle breezes towards the east. Don’t use radar and barometers; use the Farmer’s Almanac and what grandpa remembers.”

Thankfully, a week after passing through the North Carolina Senate international public criticism of the law saw it get shot down unanimously in its House of Representatives (Philips 2012). This is lucky as the in the same month, sea level in the region was reported to have accelerated by 2-3.7 mm/year meaning that changes there are 3-4 times the global average (Sallenger et al. 2012). Thus, the 1 metre predictions which North Carolina was so against may instead be 20-29 cm larger by 2100.

References

BBC (2011) ‘Is King Canute misunderstood?’ (WWW), London: BBC News (http://www.bbc.co.uk/news/magazine-13524677; 28 November 2012).

BBC (2012) ‘Virginia's dying marshes and climate change denial’ (WWW), London: BBC News (http://www.bbc.co.uk/news/magazine-17915958; 29 November 2012).

Grimm, F. (2012) ‘Commentary: add rising sea levels to the list of banned terms’ (WWW), Miami: The Miami Herald
(http://www.mcclatchydc.com/2012/06/17/152200/commentary-add-rising-sea-levels.html; 29 November 2012).

Huler, S. (2012) ‘NC considers making sea level rise illegal’ (WWW), Scientific American (http://blogs.scientificamerican.com/plugged-in/2012/05/30/nc-makes-sea-level-rise-illegal; 26 November 2012).

Leber, R. (2012) ‘Virginia lawmaker says ‘sea level rise’ is a ‘left wing term’, excises it from state report on coastal flooding’ (WWW), ThinkProgress
http://thinkprogress.org/climate/2012/06/10/496982/virginia-lawmaker-says-sea-level-rise-is-a-left-wing-term-excises-it-from-state-report-on-coastal-flooding; 30 November 2012).

Phillips, L. (2012) ‘Sea versus senators’, Nature, 486, 7404, 450.

Sallenger, A. H., K. S. Doran and P. A. Howd (2012) ‘Hotspot of accelerated sea-level rise on the Atlantic coast of North America’, Nature Climate Change, 2, 884–888.

"Everybody talks about the weather, but nobody does anything about it"

This is thought to have been a rumination made by Charles Dudley Warner way back in the 19th century. But even in the past year, the US, as well as numerous other regions of the world, have experienced extreme weather events that many have attributed to the amplification effects of climate change. Hurricane Sandy hit the east coast of America the week before the Presidential election this month and surprisingly little was mentioned in the campaign about combating climate change. This seems to me rather alarming as my previous post actually explained how rising sea levels and a changing climate were to blame. So why is so little being done by those with so much power to change?

Intriguingly, and a first since 1984, climate change was not mentioned in any of the presidential debates between Obama and Romney. Obama had stated in his 2008 Democratic nomination victory acceptance speech that:

"We will be able to look back and tell our children that this was the moment...when the rise of the oceans began to slow and our planet began to heal."

Something which Romney has since attempted to mock Obama about. At a recent Republican convention in Florida, he declared that while:

"President Obama promised to begin to slow the rise of the oceans... [he paused for a few seconds, waiting for laughter] ...and to heal the planet. My promise...is to help you and your family."

It seems obvious to me that healing that planet would go a long way to help families in the future but, as you will see in the clip of Mitt Romney below, the audience at the convention do not appear to have linked the two. As well as Obama hitting back by saying “climate change is not a hoax” (SAPA 2012), climate scientist Michael Mann has tweeted his response:

Figure 1: Tweet by Michael Mann on 31 Aug 2012

This short news segment compiling a few climate-related stories in the run up to the election also shows the moment when a heckler disrupted Romney and held up a banner which read, ‘End Climate Silence’, as well as the endorsement of New York City mayor Bloomberg, an independent, for Obama in the wake of Sandy which had ‘reshaped his thinking’ over the election, notably in relation to climate (Hernandez 2012).

It is interesting to note that a Rasmussen poll of likely US voters, the day before the election, found that 68% believed global warming was a ‘serious problem’ (Rasmussen 2012). This, they claim, is an all-time high and markedly up from 46% in 2009. Why then did Obama not use the campaign to talk climate?

Could it be the case, as leading expert on public opinion and climate Professor Edward Maibach (2012) believes, that he was influenced by a false assumption about public opinion? Maibach thinks that by taking a green position, either candidate could have won votes while not alienating other voters.

There is also the view that Obama has had little incentive to talk about climate change as he knows that any promise he makes will be shot down by Republicans in the Senate who are funded by some of the big fossil fuel companies (Monbiot 2012). This was what happened early in his term when he attempted to introduce restrictions on carbon emissions - they questioned the climate science and claimed it would impose a large economic burden.

Where climate came to Obama’s aid was in his dealing with Hurricane Sandy. It won him the backing of Bloomberg and also gave him the opportunity to assume the role of a president that cares about his people. In an interview with the BBC, former editor of the Times and Sunday Times Sir Harry Evans said that he believed Obama “had shown real leadership” during the crisis. He signed off federal aid for affected areas and importantly Sandy sparked debate about climate which so far, had been absent.

The result of the popular vote was 50.4%-48.1% in Obama’s favour. What effect did Sandy have on this result? It is hard to say. But what appears more important though is that the new president is not a climate sceptic and that they realise they do have the power to affect sea levels.


References

Evans, H. (2012) ‘How has Hurricane Sandy affected US polls?’ (WWW), London: BBC News (http://news.bbc.co.uk/today/hi/today/newsid_9766000/9766327.stm; 20 November 2012).

Hernandez, R. (2012) ‘Bloomberg backs Obama, citing fallout from storm’ (WWW), New York: The New York Times
(http://www.nytimes.com/2012/11/02/nyregion/bloomberg-endorses-obama-saying-hurricane-sandy-affected-decision.html?_r=0&adxnnl=1&adxnnlx=1353409305-CMqwX95aEfQWMfYbtbPMeA; 22 November 2012).

Maibach, E. (2012) ‘Polling expert: is Obama’s reluctance to mention climate change motivated by a false assumption about public opinion?’ (WWW), ThinkProgress (http://thinkprogress.org/climate/2011/09/08/314629/polling-obama-climate-change-public-opinion; 22 November 2012).

Monbiot, G. (2012) ‘Obama and Romney remain silent on climate change, the biggest issue of all’ (WWW), London: The Guardian  (http://www.guardian.co.uk/commentisfree/2012/nov/05/obama-romney-remain-silent-climate-change; 21 November 2012).

Rasmussen (2012) ‘Energy update - new high: 68% see global warming as serious problem’ (WWW), Asbury Park: Rasmussen Reports (http://www.rasmussenreports.com/public_content/politics/current_events/environment_energy/energy_update; 22 November 2012).

SAPA (2012) ‘Obama, Romney asked to debate climate change’ (WWW), Johannesburg: Times Live
(http://www.timeslive.co.za/scitech/2012/10/12/obama-romney-asked-to-debate-climate-change; 21 November 2012).

Hurricane Sandy - The role of rising oceans

In the space of a week Hurricane Sandy, nicknamed 'Superstorm Sandy' and even 'Frankenstorm', hit the east coast of America and there was also the small matter of electing a new president. In the long-running election campaign, neither candidate had wanted to discuss climate change so it got pushed under the rug. Even with Sandy's presence, the issue of global warming was one which Obama, the Democrat, and Republican Romney spoke very little of in terms of anthropogenic impact.

Sandy certainly had a devastating effect on a number of countries including the US. The storm is thought to be responsible for the deaths of 132 Americans, to have caused £30-40 billion of damage, and to have left 6.2 million without power (BBC 2012). New York was one of the hardest hit areas thanks to a combination of population density, its location in the Hurricane's path, and the low lying nature of many parts of the city.

The twitter feed in the margin of this blog recently came to life with stories relating to sea level and the effect that this has had on storm events such as Hurricane Sandy. Before I move on further to talk about how Sandy could have influenced the election in my next post, I will first explore why climate change is being blamed.

You may be thinking hurricanes are a natural phenomenon and this is true. So what role have humans played in causing Hurricane Sandy? Well, the answer is that human-caused climate change amplified the hurricane's impact.

Figure 1: Yellow cabs line a flooded Queens, New York street as Hurricane Sandy passes 

Climate scientist Michael Mann has noted that over the past century, Battery Park, New York, has witnessed sea level rise of about a foot (Borenstein 2012). This has been attributed to a combination of land ice melt and thermal expansion in a ratio of approximately 6:4.

Hindsight is a wonderful thing. In a paper published in Nature in February earlier this year, Lin et al. (2012: 462) warned that:

‘The combined effects of storm climatology change and a 1 m sea level rise may cause the present New York City 100-year surge flooding to occur every 3–20 years and the present 500-year flooding to occur every 25–240 years by the end of the century.’

Thus, increased warming has led to sea level rise which will amplify a storm surge and cause even greater flooding! If more notice had been taken to this study by local authorities would the damage Sandy caused have been reduced?

In addition to rising sea levels a number of other factors played a role. Warming seas have the twinned effect of strengthening hurricanes and also increasing their likelihood (Emanuel 1987). Additionally, with a warmer atmosphere which can hold more water vapour, hurricane events such as Sandy are able to pull in more moisture, enlarging the size of the storm and the amount of rainfall, resulting in increased flooding (Trenberth 2012).

The path of Sandy has been analysed by several scientists, many of whom believe that the route would have been different were it not for a high pressure blocking ridge over Greenland which diverted the storm west (Masters 2012). As the ‘blocking high’ is rare for this time of the year it is thought that a record autumn Arctic ice melt is to blame.

Consequently it seems hard to argue that climate change is not shaping the world we live in today. While it was not to blame for Hurricane Sandy, several of its effects combined to contribute to the devastation that it caused in the US and the Caribbean.


References

BBC (2012) ‘Storm Sandy: eastern US gets back on its feet’ (WWW), London: BBC News (http://www.bbc.co.uk/news/world-us-canada-20150748; 17 November 2012).

Borenstein, S. (2012) ‘Scientists look at climate change, the superstorm’ (WWW), New York: Associated Press (http://bigstory.ap.org/article/scientists-look-climate-change-superstorm; 17 November 2012).

Emanuel, K. A. (1987) ‘The dependence of hurricane intensity on climate’, Nature, 326, 6112, 483-5.

Lin, N., K. Emanuel, M. Oppenheimer and E. Vanmarcke (2012) ‘Physically based assessment of hurricane surge threat under climate change’, Nature Climate Change, 2, 11, 462-7.

Masters, J. (2012) ‘Did climate change have a role in Hurricane Sandy’s unusual track into New Jersey?’ (WWW), ThinkProgress (http://thinkprogress.org/climate/2012/11/03/1125981/jeff-masters-why-did-hurricane-sandy-take-such-an-unusual-track-into-new-jersey; 18 November 2012).

Trenberth, K. (2012) ‘Opinion: super storm Sandy - what role did climate change play in this week’s massive hurricane?’ (WWW), New York: The Scientist (http://www.the-scientist.com/?articles.view/articleNo/33084/title/Opinion--Super-Storm-Sandy; 18 November 2012).

'There once was an island'

My last post highlighted the fact that rising sea levels in the Western Pacific are placing islands and coastal areas in the region at great risk. What problems are the people there facing? How are they coping? I felt that it would be an interesting change and is important to show the stories of people that are suffering the effects of sea level rise first hand.

The trailer below shows clips from what is an hour long documentary film There Once was an Island: Te Henua e Noho telling the story of Takuu and the impact that climate change is having on the small Polynesian community there. The low-lying atoll off the 250 km off the coast of Papua New Guinea is home to around 400 inhabitants. The film follows 3 local people to show the human face of climate change. These people have to deal with the outcomes of salt inundation, coastal erosion, and flooding as well as poverty. Consequently, the decision that they face is whether to leave their island forever or stay there and deal with the changes alone.

Threat posed to islands in the Western Pacific

If you were to type into Google, ‘sea level threat’ it asks whether you want to search for ‘sea level threat in Tuvalu’ as the first option in a drop-down list. Why is this? Similarly, if you were asked to name a place that you thought was at risk of rising sea levels you might well name an island, such as Tuvalu or Kiribati, in the Western Pacific. Increasingly the media has focused on these islands where it is claimed climate change is real and impacting heavily on peoples’ lives.

Figure 1: Western Pacific Islands

The region, containing a number of small, low-lying, and densely populated islands in the tropical Western Pacific is often thought of as one of the most vulnerable places in the world to future changes in sea level (Nicholls and Cazenave 2010). Part of the problem is that average land elevation on this islands rarely exceeds 3 metres above sea level. Nicholls et al. (2007) argue that a combination of natural stresses and human activities could combine with sea level rise to pose an even greater threat to life on these volcanic archipelagos made up of islands and atolls. This includes ground movement caused by tectonic activity and volcanism, extreme climatic events such as storm surges, subsistence as a result of water or oil extraction, and increased pressure on the land due to urbanisation.

While average global sea level measured from tidal gauges since 1950 pointed to an increase of around 1.7 mm/year, my previous blog highlighted two important factors that need consideration (Church and White 2006). Firstly, new satellite altimeter readings have found that this rate is closer to 3.3 mm/year for the period since 1993 (Ablain et al. 2006). In addition to this, sea level is not uniform around the world meaning global averages hide extreme rises (and falls). A further issue is that of timescale as measurements can be obscured by annual or even seasonal fluctuations. Satellite altimeter measurements of the western tropical Pacific region have shown an increase of about 3 or 4 times the global average between 1993 and 2010 but this must be taken with caution due to the relatively short time period examined (Becker et al. 2012).

Becker et al. (2012) and Church et al. (2006) have both investigated changes in sea level in the Pacific Island region which meant overcoming problematic data sets and using a number of different types of measurement data, as well as removing factors that caused short-term fluctuations. While tidal gauge records go back much further in time than satellite observations, they contain gaps and also lack the accuracy of satellite records as they are fixed to the seabed thus relying on it not rising or sinking. To counter this effect, GPS data was used to account for vertical land movement making way for sea level change reconstructions to be formed. This found that ‘ground subsidence increases the [total] climate-related sea level rise by about 10%’ (Becker et al. 2012: 97).

Figure 2. Becker et al. 2012 (Funafuti is an island of Tuvalu)

A further consideration that I have touched upon is that of seasonal or annual variation. This is especially relevant for the Pacific as it is this region that is heavily influenced by El Niño-Southern Oscillation (ENSO) events. This is because La Niña causes a tilting of the thermocline which results in water piling up in the tropical western Pacific while El Niño reduces this tilt meaning water levels out over the Pacific (Church et al. 2006). Consequently, during La Niña, sea levels around Tuvalu rise and in an El Niño phase they fall. The magnitude of sea level variability due to ENSO events was found to be around 20-30 cm above or below average levels in the Tuvalu region (Becker et al. 2012). They therefore have an enormous impact on inter-annual variability as it results in between 40-60 times the annual sea level rise here.

There are two key reasons why ENSO effects were examined. Firstly to explore the magnitude of change caused by them and secondly, to explore how much sea level is altering in this particular region when short-term fluctuations are removed. When this is done, and new models of combined data have been used to reconstruct sea level models, long-term changes can be calculated. Becker et al. (2012) found that sea level rose at a rate of 5.1 (±0.7) mm/year during the period 1950-2009 at Tuvalu. This is a gigantic rise and is exactly 3 times as large as the global average figure mentioned above. Thus it is clear to see now why there is so much media coverage of the impacts of climate change impacting on these low-lying islands and their people. Future posts will look at their perspectives and responses to these changes.


References

Ablain, M., A. Cazenave, G. Valladeau and S. Guinehut (2009) ‘A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over 1993–2008’, Ocean Science, 5, 193-201.

Becker, M., B. Meyssignac, C. Letetrel, W. Llovel, A. Cazenave and T. Delcroix (2012) ‘Sea level variations at tropical Pacific islands since 1950’, Global and Planetary Change, 80–81, 85–98.

Church, J. A. and N. J. White (2006) ‘A 20th century acceleration in global sea-level rise’, Geophysical Research Letters, 33.

Church, J. A., N. J. White and J. R. Hunter (2006) ‘Sea-level rise at tropical Pacific and Indian Ocean islands’, Global and Planetary Change, 53, 155–168.

Nicholls, R. J. and A. Cazenave (2010) ‘Sea-level rise and its impact on coastal zones’, Science, 328, 5985, 1517-1520.

Nicholls, R. J., P. P. Wong, V. R. Burkett, J. O. Codignotto, J. E. Hay, R. F. McLean, S. Ragoonaden and C. D. Woodroffe (2007) ‘Coastal systems and low-lying areas’, Climate Change 2007: impacts, adaptation and vulnerability. Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 315–356.

Ocean Fingerprints

So did you get round to watching the talk? I hope you enjoyed it if you did but don’t worry if you didn’t have time. My previous post highlighted the 3 key arguments that sceptics make and I shall try to explain how Mitrovica attempts to show why he believes each is false.


1) 2 mm/year is not anomalous – sea level has been rising at this rate for thousands of years.

Geological evidence - Equatorial corals, which are about 3m above sea level, have been found to be 5000 years old. If the sea had been rising at a rate of 2 mm/year these would be 10m underwater.

Archaeological evidence - Fish tanks (piscinae) in the mediterranean carved into the rock during the 2nd Century and early 1st Century BC were built at a precise height relative to sea level to enable the movement of water but not fish. Measuring current elevation relative to high tide (and correcting for vertical tectonic movement) leaves a rise of about 1 metre which equates to a 0.5 mm/year rise. Correcting for ice age effects, there has been very little change at all over the past 2000 years (Lambeck et al. 2004)! If it had been rising at 2 mm/year these tanks would be 4 metres under.

Ancient eclipse record evidence -
Stephenson and Morrison’s (1995) study suggests the Earth’s rotation is slowing down due to water waves breaking and causing a dissipation. Taking into account this effect, the Earth’s current rotation rate matches up with ancient eclipse records. If ice sheets had been melting during this time, large amounts of water would have been added meaning slower rotation. Consequently, ice sheets could not have been melting for the past 2000 years!

- Therefore, 2 mm/yr in 20th C was anomalous. nothing has been seen like it during the past 10,000 years. Bjork (2011: 5) certainly believes this is the case as recent trends have been ‘triggered by anthropogenically forced alterations of the carbon cycle in the general global environment’.


2) Sea level change varies dramatically from place to place – melting ice sheets cannot be the culprit.
They do indeed vary. By thinking like this and taking the average of different tide gauge records around the globe you are assuming the ‘Bathtub Model’ (see below).

Ice Sheet melt and resultant sea level change

The problem with this is that when an ice sheet melts the sea doesn’t rise uniformly (Mitrovica et al. 2009). Instead, because ice sheets have mass, they exert a gravitational pull on the nearby water. When a sheet melts, the pull on nearby water is relaxed and more water is added. The result of these two factors near an ice sheet is a drop in sea level (see above). The implications for this are global differences in sea level. There is a hinge point around 2000km away from the melt where there is observable sea level rise. 

Global differences in sea level change

‘Sea level fingerprints’ is the name given to the pattern of sea level change and this can change depending on which ice sheets melt . This does mean though that fingerprint analysis can be carried out to predict the outcomes and potential risks of different ice sheets melting separately, or even in combinations.

3) Even so, 2 mm/year is small and stable.
Well, this rate already has changed! Satellite data from altimeter satellites has been measuring sea level in recent years and this has found that the rate is closer to 3.3 mm/year in the last decade (Ablain et al. 2006).



References

Ablain, M., A. Cazenave, G. Valladeau and S. Guinehut (2009) ‘A new assessment of the error budget of global mean sea level rate estimated by satellite altimetry over 1993–2008’, Ocean Science, 5, 193-201.

Bjork (2011) ‘Current global warming appears anomalous in relation to the climate of the last 20,000 years’, Climate Research, 48, 5-11.

Lambeck, K., M. Anzidei, F. Antonioli, A. Benini, A. Esposito (2004) ‘Sea level in Roman time in the Central Mediterranean and implications for recent change’, Earth and Planetary Science Letters, 224, 563-575.

Mitrovica, J. X., N. Gomez and P. U. Clark (2009) ‘The sea-level fingerprint of West Antarctic collapse’, Science, 323, 5915, 753.

Stephenson, F. R. and L. V. Morrison (1995) ‘Long term fluctuations in the Earth’s rotation: 700 BC to AD 1990’, Philosophical Transactions: Physical Sciences and Engineering, 351, 1695, 165-202.