The Last Post

Unfortunately all good things must come to an end, and with the deadline for this blog looming it is time to wrap it up!

Having come into this blog with a reasonable understanding of SLC, I think I have come to appreciate how large the impacts of SLR could be. The processes and causes of SLC are now well understood however it is clear that uncertainty about the rate and magnitude of the individual contributions to SLC mean that not enough action is being taken to mitigate against SLC (apart from some countries... Well done the Netherlands!). This piece makes an interesting point about the link between uncertainty and inaction, while there is uncertainty around SLR it is definitely happening, the uncertainty is quite how bad it will be... 

Seeing how close so many people in Bangladesh and other places around the world are to being forced to migrate as a result of SLR it is going to become an increasing pressure on decreasing land mass. I shall leave you with this graph from the IPCC projecting SLR by 2100 under varying emissions scenarios. I'm slightly more positive today about the likelihood of emissions reductions following the news that China is about to plough $361 billion into renewable energy by 2020. So hopefully China's example will be followed, emissions will begin to fall somewhat, and we will be looking at better scenarios in the next IPCC report... Although some studies, particularly those using the semi-empirical modelling approach to SLC (e.g. Rahmstorf, 2007) project it could be much more by 2100, kinematic constraints on glacier melting suggest it will be no more than 2 m by 2100. 

IPCC predictions of SLC by 2100. Source

The potential rise in sea level could be devastating and as I contended in my first post, I still believe that SLC is one of the 'quiet' agents of Climate Change and far more awareness of the potential problems it will cause is required. As the Netherlands have showed, effective mitigation is possible but before people realise how compromising SLC can be, it could already be too late. Try and be prepared just like the Statue of Liberty is (below)!

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Bangladesh: Slipping into the sea?

A slightly backwards post today, the film below is quite long, but gives an excellent introduction to the problems Bangladesh is having with Climate Change and particularly SLR. For those without the time to watch the film the main body of the post is below:

  

So why so much interest in Bangladesh? As the film suggests Bangladesh is stuck in the middle of SLR and flooding by its great rivers due to increased melting in the Himalayas as a result of climate change. It is often cited as the country most at risk of Climate Change, and essentially the majority of the country is one large floodplain (see below). Karim & Mimura, (2010) find that only a small rise in sea level could be catastrophic to significant areas of the coastal zone, and similar to the USA as mentioned in my recent post, storm surging during tropical cyclones could exacerbate this effect. From the map below it is clear that any SLR could lead to catastrophic flooding.

Land height above SL in Bangladesh. Source

As I mentioned in my post on groundwater depletion, the subcontinent is one of the areas that undertakes a lot of groundwater extraction which can lead to SLR. This is a further pressure on the country meaning SLR could have a greater effect with land subsidence leading to more area becoming at risk of SLR (Brammer, 2014). The majority of Bangladeshis rely on agriculture for their income, running subsistence farms. With the projected loss of land expected to especially hit agricultural areas, people will be squeezed out of their livelihoods (Dasgupta et al., 2007). 

Bangladesh at least has begun to implement a National Adaptation Programme of Action (NAPA), based on UN standards to try and have a country wide project to mitigate against climate change. However as one of the Least Developed Countries with a GDP/capita of just $1,211, they lack the funding to implement large schemes such as those seen in the Netherlands or other developed countries. Therefore as outlined in the NAPA it is likely that Bangladesh will be forced to rely on aid to implement any adaption or mitigation programmes. This raises the question which I have not touched on too often: the main contributors to the climate change that is causing SLR. Bangladesh has contributed very little to climate change in terms of greenhouse gas emissions, but will be one of the first countries to feel the catastrophic effects. Considering projections suggest 17% of the land area is expected to be submerged by 2050, displacing 18 million people in the process, this is a ticking time-bomb. The response of the government is considered by many to be inadequate, with dredging programs and building of levees possibly exacerbating the situation.

Pethick & Orford, (2013) present an interesting study that suggests rates of SLR in Bangladesh are not actually the critical pressure on Bangladesh, more that increasing population and the lack of available land, but that SLR will affect increasing numbers of people. They project SLR in Bangladesh to be significantly above the global average meaning even more people could be at risk in the near future. This is due to an expanding tidal range due to both GMSL rise and subsidence of deltas. The study appears somewhat doubtful in the magnitude of SLR but is clear in needing an integrated action plan to help adapt and mitigate to the problems Bangladesh face. This is supported by Brammer (2014) who believes SLR at its current rate will not make a massive difference to Bangladesh but population pressures are again the critical problem. 

For me it is apparent that population pressures are crucial in Bangladesh but the studies still downplay the potential impacts of SLR; many other countries have population pressure but Bangladesh's problem with SLR means it is one of the most at risk and SLR will continue to compound it.

Florida and SLR

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A cartoon depicting the 'positive' side of SLR in Florida. After my last post, this made me laugh!

Tropical Storms and SLR: The Perfect Storm?

In my introductory blog I mentioned how SLR was affecting the damage caused by major hurricanes including Sandy (2012) and Matthew (2016). Now as a Christmas present to my dear readers I will (finally!) address this and show how the small incremental change of SLR is having a large effect on the damage that these hurricanes are causing.

Along with the projected increase in cases of extreme (category 4 & 5) hurricanes in the future as a result of climate change (Goldenberg et al., 2001), SLR is projected to increase which means that storm surges associated with hurricanes will inundate further affecting more and more infrastructure and homes. A significant amount of the damage caused by Hurricane Matthew has been attributed to storm surging, while Hurricane Sandy saw large parts of New York under water. 

Flooded taxis in New York following Hurricane Sandy. Source

There is an element of luck to how bad a storm surge will be, if the peak surge coincides with high tide then that can raise the height of the surge by many metres. This occurred during Hurricane Sandy in New York, causing significantly more damage than had it been at low tide. The acceleration in SLR (see below) is being particularly affected by thermal expansion with a further acceleration being reported in the last decade (see below), disproportionately so on the Atlantic Coast of North America (Rietbroek et al., 2016). This is thought to be due to a combination of meltwater fingerprinting and changing ocean cycles as I have indicated in earlier posts, the regional signal of SLC is critical in some areas.

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Hurricane Matthew caused up to $6 billion of damage in both Haiti and America, with the state of North Carolina experiencing $1.5 billion worth of damage alone. SLR contributes significantly to this due to the rising of the base sea level, so what would have caused less flooding 100 years ago now causes significant amounts of flooding (see video below). Despite this officials in the Florida Department of Environmental Protection are not allowed to use the phrases ‘climate change’ or ‘global warming’ . Apathy to this issue will allow for SLR to continue to affect America, and despite this Florida, one of the most at risk areas doesn’t have a state-wide action plan to deal with climate change. As I showed in last week's post, The Netherlands' well-defined and wide ranging action plan significantly mitigates the effect SLR can have therefore it is very surprising that Florida don't have an action plan that could save lives and billions of dollars in the long run.

  

It is clear that hurricanes can cause significant coastal flooding which can be exacerbated by SLR. A paper by Woodruff et al., (2013) compared present day situations to early Holocene records where rapid SLR was experienced. Using past conditions can act as an analogue for the present and the future so to look at periods where similar conditions were experienced has certainly informed on the potential future tendencies They found that during the early Holocene SLR meant low-lying coastlines had low resilience to storm impacts. In addition they found that the worst storm surges are caused when winds are highest, considering storm activity is projected to increase with the strongest storms having the greatest effect (Zhang et al., 2001), it is likely that with SLR and increased activity coastal flooding could worsen. This is particularly likely in low-lying areas such as Bangladesh, where inundation of significant land area has been modelled to be very likely by 2050 (Lin et al., 2012). The suggestions of Woodruff et al., 2013 appears valid as it is very likely in the future a combination of SLR and increased storm activity could significantly affect coastal areas. This is supported by Mousavi et al., (2011) who modelled that even by 2030 as a result of SLR, surges could be up to 0.3 m higher in the USA, and by 2080 0.8 m higher. Considering they found this to likely be on the lower end of estimates due to unmodelled uncertainties, the effects of storm surging and the economic and human damage that it can bring will be significant.

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It is apparent that SLR is having a significant effect on the destructiveness of storms. Raising the base sea level means storms like Sandy and Matthew cause far more damage than they would have 100 years ago and with projected increased storminess, governments need to get a handle on the potentially catastrophic effects. So Florida, get your act together!

Adapting to SLR: Britain and the Netherlands

Having discussed some of the areas most at risk of SLC, I think it is important to come a little bit closer to home to discuss SLC around Britain and mitigation strategies being adopted. 
This interest has been further piqued by this article from Monday suggesting massive differences in the spending for flooding across Britain with half of national spending targeting the London area Britain is at a very interesting point of SLC, due to its location and past glaciation meaning that Scotland is rising out of the sea while southern Britain is slowly sinking below the waves… The UK is considered the 12^th most at risk country in terms of population that could be directly affected by SLC with 4% of the population at risk. 

It also has many coastal communities and people living at risk of SLC. Flood adaptation and mitigation strategies are managed by the Environment Agency (EA) who have a national-scale Shoreline Management Plan (SMP) to try and provide a long term assessment and plan for managing the effects SLC may have. This attempts to move away from the previous consensus that the only method is the hold the line method of building sea walls (see below) and other coastal defences when a more holistic approach is often required. Even sea walls have been redesigned to mimic natural conditions more effectively (see below).

Blackpool's Victorian Sea Wall. Source

Blackpool's new sea wall is designed like a sand dune to dissipate wave energy more effectively than the old Victorian Wall. Source

The full SMP can be found here which shows a variety of methods are to be employed in order to mitigate the effects of SLC. The UK is divided into a series of zones for which regional SMPs are created. These are divided into four main approaches and defined by the EA:

1. No active intervention – There is no planned investment in defending against flooding or erosion, whether or not an artificial defence has existed previously.
2. Hold the (existing defence) line – An aspiration to build or maintain artificial defences so that the position of the shoreline remains. Sometimes, the type or method of defence may change to achieve this result.
3. Managed realignment – Allowing the shoreline to move naturally, but managing the process to direct it in certain areas. This is usually done in low-lying areas, but may occasionally apply to cliffs.
4. Advance the line – New defences are built on the seaward side.

Although these approaches appear fairly set in stone, Nicholls et al., 2013 suggests that adaptation pathways are a more effective way of approaching coastal change as a result of SLC. This suggest that with monitoring of SLC and coastal change, a range of strategies for each section of coastline that are flexible should be planned for allowing action to be taken depending on the reaction of the coast. This approach has been considered very controversial in some areas, with areas considered higher value often protected at the expense of less valuable areas. This has led to suggestions that there is a bias towards more affluent areas as they are considered of higher value. Therefore to placate all stakeholders in the management of SLC requires significant work and can lead to a slowing of the process by which flood defences and strategies are implemented.

Clearly mitigation of SLR is crucial, as this website shows where you can have a look at the world map with different levels of SLR in the future. For instance for a 7 m rise (albeit nearly impossible before 2100), sees large parts of Eastern England under water and London in serious trouble, which explains the clamour to build a second Thames Barrier to protect London. This is supported by the significantly increased numbers of closures in recent years of the Thames Barrier (see graph below). The danger to London remains the case for a 2 m rise (possible but very unlikely by 2100), and coupled with the increased number of closures suggests why the government commissioned a white paper called Thames Estuary 2100, recommending a Thames Barrier 2 be built to mitigate potentially catastrophic flooding in central and east London. 

Number of closures of the Thames Barrier since 1982. Source

Having said how at risk we in the UK are, at least we aren’t in the Netherlands… Even with SLR of just 1 m (perfectly plausible by 2100) more than half the country is expected to be inundated. This is because much of the Netherlands is below sea level but protected by a sophisticated series of dams, dykes and levees. Comprehensive coastal defence plans are in place for the whole of the Netherlands and are expected to hold for the next few decades, however late into the 21^st Century whether they will be able to continue to cope is very much uncertain (Monabilu et al., 2014)  Large scale adaptation and mitigation infrastructure projects such as the Sand Motor (see video) attempt to manage the coastline in a way that both maintains the natural environment while providing additional buffering against SLR. This holistic approach works in tandem with more infrastructure heavy projects which protect the areas below sea level from SLR.

It is clear that Britain and particualrly the Netherlands are at significant risk of SLR but with long-term view adaptation and mitigation plans it is possible to reduce the effects of SLR. Along with this a drop in greenhouse emissions is required so that the rate of SLR doesn't get to a point where it is out of control and mitigation will be almost impossible.

Kiribati- A climate change reality

A short follow up post today with a very important video building on last week's post. The video below shows quite how dangerous SLR could be to low-lying islands. It aims to raise awareness of this creeping menace that is very difficult to stop.

 

For an assessment of the potential effects of implicating mitigation strategies Tol, 2007 provides an interesting suggestion of the possible costs by 2100. Low-lying islands such as Kiribati feature highly in spending as a percentage of GDP and percentage of land at risk of SLR. The main feature of the paper is the assertion that money is better spent on adaptation rather than purely trying to block SLR, and in the long term this can greatly reduce cost that damage caused by SLR would cause.

On the frontline of Sea Level Rise

So the blog is going to have a bit of a change of direction… Having covered all of the major physical processes that affect SLC I now feel able to spend some time investigating case studies across the world of the places and people directly at risk of SLR.

Low Lying tropical islands are most at risk of SLR, indeed the inhabitants of these islands may become some of the first Climate Change refugees. Despite the recent COP21 Paris agreement on emissions reductions, the Prime Minister of Kiribati suggests it will not be enough to prevent these islands slipping into the sea. 

Welcome to the Maldives, a paradise archipelago of atolls and islands in the Indian Ocean. The Maldives hit the headlines a few years ago when their government held a cabinet meeting under the sea in order to highlight the potential effects of SLR. The Maldives will be at the forefront of SLC, its highest point lies just 2 m above sea level. 

The Maldives

Although this is by no mean a laughing matter, I came across a cartoon that rather accurately depicts the potential plight of these small island nations.

Cartoon about potential SLR. Source

In the Solomon Islands, for some it is already too late. 5 islands have been reclaimed by the sea (see below) as it experiences above GMSL average rise. This created headlines worldwide, with most major news outlets picking up on this issue. The global SLR rise of approximately 3 mm/yr, is dwarfed in this area with estimates of an acceleration up to 7mm/yr (Albert et al., 2016). Although SLR is clearly the dominant cause of threat to these low-lying islands, studies have indicated that human activities have also accelerated the degradation of the land. Inappropriate development choices, including the building of sea walls has accelerated erosion and led to the abandonment of islands as it became entirely unsustainable to live there. It is however not all doom and gloom; Webb & Kench, 2010 suggest that many islands are dynamic in their response to SLC and used quantitative analysis to reveal that 86% of low-lying islands in their study were either stable or growing in area despite SLR. This is because islands respond to a variety of factors, of which SLC is just one of them. Although this may indicate a positive trend for now, with SL rising continually and the rate of rise likely to increase a threshold will be passed by which many of these islands will become inundated. 

One of the Solomon Islands that has been lost to SLR. Source

Even if SLR doesn’t leave islands uninhabitable there have been suggestions that SLR will cause a slightly different effect that will still leave inhabitants in serious trouble. As sea level rises, the level of groundwater rises as well (Gulley et al., 2016). Therefore as this paper suggests the important freshwater can leak into lakes or create new ones which results in increased evaporation. As my last post indicated, groundwater depletion can have a significant effect on SLR but the effect here would be twofold: water is a precious resource in these areas, and the land use change could also be significant.