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.

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.