Natural Disasters and the Risk of Disease Epidemics

Following a natural disaster, the impacts can often be long-lasting, owing to damaged infrastructure, loss of agricultural land, businesses, and so on. A key concern also includes the sudden risk of disease epidemics, as vulnerability to disease increases after a disaster. Interestingly, vulnerability to natural hazards can also be exacerbated by disease - as well as other variables such poverty, conflict and population displacement (Basher, 2006). Developing countries are disproportionally affected as they lack resources, infrastructure, and disaster-preparedness systems (Watson et al., 2007).

The type of diseases that a natural disaster can exacerbate vary. After the 2004 Bangladeshi floods, contaminated drinking water caused the outbreak of diarrhoeal disease, found in over 17,000 cases (Watson et al., 2007). A large cholera epidemic (over 16,000 cases) was also noted in West Bengal in 1998 which was attributed to the preceding floods (Sur et al., 2000). Diseases such as tetanus and clusters of measles had spread following the 2005 Pakistan earthquake - particularly when routine vaccination coverage levels were low.

Pakistan earthquake 2005. Source

A common misconception is that diseases following a natural disaster are mostly spread from dead bodies, and thus this can lead to inappropriate burial of the dead without proper identification (Morgan, 2004). The most dangerous conditions are when dead bodies have contaminated water supplies; gastroenteritis being the most notable problem as corpses will commonly leak feaces - although communities will rarely use a water supply is they know it to be contaminated. Watson et al. (2007) argue that dead bodies can pose a serious health risk in a few situations that require specific precautions, such as deaths from cholera or hemorrhagic fevers. However (Morgan, 2004) contests this, stating that the causative agents in infections such as typhoid and cholera are unable to survive long in the human body following death, and therefore dead bodies pose little risk.

Rather, the main initiator of disease is reported to be displacement of a population following a natural disaster. This is due to overcrowding, limited water and sanitation supplies, and poor medical facilities which increase the risk of communicable disease transmission. The risk of outbreaks is associated with the size, health status and living conditions of the population displaced by the natural disaster.

Meterological events such as hurricanes, cyclones and flooding can affect vector breeding sites and vector-borne disease transmission (WHO, 2006). Standing water which is a result of heavy rainfall or overflow of rivers can create new breeding sites for mosquitoes. In a displaced population, there is an overcrowding of susceptible hosts coupled with a weakened health infrastructure and interruptions of ongoing disease control programmes, which contribute as risk factors for vector-borne disease transmission. Changing of habitats resulting from landslide deforestation, river damming and re-routing can also contribute to mosquito breeding.

As global environmental change is likely to exacerbate vulnerability to vector-borne diseases (e.g. malaria and cholera), it is important for disaster mitigation strategies to acknowledge the potential increase in secondary impacts such as disease epidemics resulting from hazards. Perhaps a most suitable solution, following this research, is to carry out effective strategies to avoid overcrowding when a population is displaced, and to provide more immediate substitute water and sanitation supplies to the effected population. What do you think is a suitable strategy to deal with disease outbreaks?

Re-meandering and Rewilding River Systems: An Effective Flood Management Strategy in the UK?

   Storm Desmond was an extratropical cyclone; so far has the fourth named storm of the 2015-16 UK and Ireland windstorm season. Desmond was notable for directing a plume of moist air, known as an atmospheric river, which brought record amounts of orographic rainfall to uplands areas of northern Atlantic Europe and subsequent major floods. The worst affected areas in the UK were centered on Cumbria, Lancashire and the Scottish borders, with severe rain and flooding also reported in Northumberland, north Wales and Yorkshire. The storm broke the UK's 24-hour rainfall record, with 341.4 mm of rain falling in Honister Pass, Cumbria on the 5th of December (Met Office, 2015). As a consequence, 43,000 homes across the north of England were left without power, 3 people died and the damage cost £400-500 million. The damage was not solely confined to human impacts, however - ecology was also greatly harmed. For example, this somewhat flippant article from The Metro about a ‘sad otter’ does actually demonstrate that flooding can be a very hazardous time for young otters; they can easily be washed out of their holts by high rivers, and at that age are not accomplished swimmers.

River Eden burst its banks in Appleby due to Storm Desmond. Source

   On Tuesday 8th December, on the Today Programme on Radio 4, George Monbiot - an environmentalist - and Meurig Raymond - the President of the National Farmers Union - engaged in a debate over the impacts and possible causes of Storm Desmond flooding in the North of England. I thought this debate very fitting to my blog, it distinctly fits in well with my previous blogpost on Storm Abigail. With extreme weather events set to increase with climate change, it is vital that we look at ways to mitigate flooding effectively, particularly with the devastating impacts flooding has on urban areas. You can get the podcast of this debate here, at 2:48:00 into the episode.

   George Monbiot is an accomplished writer, known for his environmental and political activism, and weekly column in The Guardian. In this debate, he first began by outlining the issue with current flood mitigation strategies: instead of preventing the flood from happening, we wait and act after it has hit. We should, he argued, use soft engineering approaches as a flood prevention strategy, such as reforesting bare hills and rewilding river systems. This is for a number of reasons - by reforesting hills, the percolation rate into the soil will increase and therefore water is released more slowly. Additionally, by rewilding rivers and allowing them to meander, to form islands and banks of gravel and shingle, the river system will become more dynamic, and the flow of water will be held back.

   The processes of channelisation and river dredging were described by Monbiot as turning rivers into ‘straight drains’, whereby water bypasses farmland, but subsequently then rushes into the nearest settlement. Furthermore, bare hilltops produced from pastoral grazing has meant that too much water cascades down hillslopes that rivers are unable to contain; either water is allowed to spread over agricultural land, or it is sped past farmland through dredging and channel clearing, whereupon it comes down to the nearest ‘urban pinchpoint’ - such as a bridge. The resulting impact is the flooding of homes and the threatening of lives. To illustrate his point, Monbiot drew upon the example of the River Liza in the Lake District, where rewilding strategies meant that even after the last massive rainfall in 2009, the river was still running clear as all other rivers in the surrounding areas were bursting their banks.

Meandering River Liza in Ennerdale. Source

   In contrast, Meurig Raymond stance on flood management differed greatly, advocating hard engineering techniques. He argued that the flooding impacts from Storm Desmond resulted from too little investment in river dredging, channel clearing and flood defences - and that there should be more money set aside for maintenance of rivers to keep channels clear. One of his main defences of hilltop farming was that it attracted tourists into north, due to farming practices shaping the tapestry of land in an aesthetically pleasing manner. Sheep farming, food production, and agriculture, he argued, are vital to maintain wealth created by the tourism industry. Interestingly, and rather unexpectedly, Raymond stated that livestock numbers are now falling, and vegetation is increasing overall, with undergrazing now causing a larger problem than overgrazing. Therefore, water is being held back by the current fabric of the countryside. He rounded off the debate by stressing the importance of agriculture - as both a creator of top quality beef and lamb, but also as a generator of wealth.

Bare hills in Cumbria due to hilltop farming. Source

  The majority of the public listening to the debate seemed to concur with Monbiot’s opinion - that rewilding river systems can prevent flooding (shown through the handle @BBCr4today on Twitter). However, farmers have expressed anger at Monbiot’s seemingly ‘anti-farming’ rhetoric, expressed in his various articles and interviews, and argue that he has little knowledge of hilltop farming practices. Personally, I agree with Monbiot; I think rewilding river systems would be an incredibly beneficial mitigation strategy to control flooding. What do you think - is rewilding a viable solution, or has land-use changed so much that it is near impossible to go back to such an environment?

Japan Case Study Part 2: How The Tohoku and Fukushima Disaster Changed Public Opinion on Nuclear Power as a Low Carbon Energy Source

When I first visited Japan on a 3 month travelling trip, it was one and a half years after the magnitude 9 Tohoku earthquake and tsunami that hit northern Honshu in 2011. I had met some people in youth hostels there who were international students studying in Sendai temporarily, who still described Sendai as a 'complete wreck' from the disaster. Having just come from Tokyo, the stark difference in damage between the two regions was palpable, and contamination from the Fukushima nuclear disaster was still being reported worldwide.

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  The Tohoku earthquake struck offshore of Japan, along a subduction zone where two of Earth’s tectonic plates collide, with the tremor releasing centuries of build up stress between the Pacific and the Eurasian plates. The fault contained a slippery clay layer which lined the fault, which researchers believed to have allowed the two plates to slide an enormous distance of around 50 meters. The earthquake began on the 11th March, at 2.46pm local time, and lasted approximately six minutes. The epicenter was centered on the seafloor 45 miles east of Tohoku, at a depth of 15 miles.

  The earthquake caused a confirmed death toll of 15,893 as of the 10th November 2015, according to Japan’s National Police Agency. The majority of deaths were caused by drowning from the destructive tsunami waves that reached heights of up to 39 meters. Many of Japan’s coastal flood defences were decimated from the impact.

  Perhaps one of the most devastating impacts from the tsunami was the resulting ‘nuclear meltdown’ in Fukushima, which caused a cooling system failure at the Fukushima Daiichi Nuclear Power Plant and the subsequent release of radioactive materials. The tsunami, which reached 13 meters tall in this area, completely overwhelmed the 10 meter sea wall put in place to protect the plant. Trace amounts of radioactivity, including iodine-131, caesium-134 and caesium-137 were widely observed, causing the worst nuclear accident since the 1986 Chernobyl disaster. In July 2013, the Tokyo Electric Power Company (TEPCO) admitted that around 300 tonnes of radioactive water continued to leak from the plant everyday into the Pacific Ocean.

A fire at the Fukushima Daiichi Nuclear Power Plant resulting from the tsunami. Source

  Unsurprisingly, the Tohoku disaster completely changed public opinion on nuclear power, both nationwide and internationally. The Fukushima disaster came at a time of global resurgence in nuclear energy facility development, with an estimated 360 gigawatts of additional nuclear generating capacity projected to be developed worldwide by 2035, on top of the 390 gigawatts already in use (IEA, 2010). The renewed interest in nuclear energy is in part due to its potential as a low carbon energy source, but also due to concerns about energy security as demand for energy is growing worldwide (Butler et al., 2011). In the case of Japan, government adopted policies aimed at improving energy efficiency and reducing the demand for oil by harnessing nuclear power, resulted in Japan becoming the most energy-efficient country in the world (The Economist, 2011). However, since the disaster, Japan has dropped to number six (Young et al., 2014). This is due to dwindling public support and policy changes on the use of nuclear power after Fukushima (Vivoda, 2011), with Japan increasing consumption of fossil fuels to make up for the loss of nuclear power.

While the full extent of the events at Fukushima were still rippling through global energy policy discourses, there was seen to be a deeper understanding of the risk of nuclear power, and a withdrawal of policy support particularly in Japan. There were also clear implications of the accident on government spending: the expenditure for compensation alone was estimated to be $124 billion (McCurry, 2011). Subsequently, significant proportions of the public in Japan and in other countries withdrew their support for nuclear power, shown in Figure 2. Similarly, Visschers and Siegrist’s (2012) paper on acceptance of nuclear power showed that in Switzerland, acceptance, perceptions and trust of nuclear power significantly decreased after the Fukushima accident.

Figure 2: Respondents who opposed nuclear energy to produce electricity either: a. previously to the Fukushima disaster; or b. recently due to the disaster in 2011. Poll conducted in April 2011. Source

Although the Fukushima disaster may have killed much of the momentum that nuclear power had gained, many still argue that nuclear power is a safe energy alternative and that the disaster resulted from insufficient safety regulations in Japan - which apparently does not exist in the USA (Stoutenborough et al., 2013). Similarly, in the UK, policymakers remained firm on their decision to increase nuclear power generation in the near future (Wittneben, 2012), which may have stemmed from limited media coverage due to the deployment of UK ground troops into Libya soon after. 

Overall, the truth remains that nuclear power offers a viable low carbon solution to feed the world's growing energy needs. At COP21, experts warned that renewable energy offers 'too little too late', and that policy makers should embrace nuclear power as an alternative to fossil fuels. Has the world already forgotten the tragedy of the Fukushima disaster - or have advances in nuclear power regulations made its use more safe? With environmental change set to increase the frequency of natural disasters, are we at risk of another serious nuclear contamination? Let me know what you think!

Japan Case Study Part 1: hazards, risks, vulnerability and mitigation

Hi everyone! Sorry for the delay in posting ! This post is going to give a very brief introduction to natural hazards in Japan, and will also mention a couple of mitigation methods the Japanese government is implementing/planning to implement. Any comments greatly appreciated :)

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   Japan is a country comprised of a series of islands in the western Pacific Ocean, and is an example of an arc-trench system, situated in a subduction zone between the margins of 4 tectonic plates: the North American, Eurasian, Philippine and Pacific plates (GLGArcs, n/a). Many of the islands are volcanic (the largest island being Honshu - home to Tokyo, Kyoto and Hiroshima) and are therefore characterised by a multitude of natural hazards. These include earthquakes, volcanic eruptions, tsunamis, mass movement and typhoons.

   In contrast to Ladakh, which is a low-income region, Japan has a GDP per capita of £25,362 and is currently the 3rd largest economy in the world. There is a huge difference in adaptability and mitigation between Ladakh and Japan, Japan has some of the most complex and expensive disaster mitigation management - although this is unequal between different regions.

Tectonic plates margins in Asia. Source

   Tokyo has been listed as the top city most at risk of natural hazards in the world, with the amount of vulnerable people in the Tokyo-Yokohama exceeding over 57 million (USA Today, 2013). However, Tokyo, due to its high wealth and capital manages to mitigate many of the hazards effectively. For example, in part of the response to the Tohoku earthquake in 2011, a 10 year project to promote earthquake-resistant joints was undertaken, whereby the replacement of 5,000 km in length of existing joints would be replaced by earthquake resistant ones. So far, the share of earthquake resistant joints has exceeded 35% (Mochizuki, 2015).

   Additionally, Tokyo has implemented an emergency water supply system, tested for quality each year, which would be able to supply the whole population of Tokyo should a natural hazard strike (Waterworks, 2012). In total, there are approximately 203 emergency supply bases across Tokyo (Mochizuki, 2015). These sources are reliant on community participation, with Tokyo Waterworks implementing training with local residents at each supply base. It provides a stark contrast to Ladakh, where any high magnitude earthquake would completely cut off water supply.

   I have already touched upon Japanese ‘earthquake-proof’ building design in a previous post, but Japan is now turning much of its attention to tsunami mitigation. A 400 km long sea wall along the North-East of Honshu, near Sendai is currently being constructed (where the devastating magnitude 9 Tohoku earthquake and tsunami hit in 2011 - but more of that in my next post!) to protect residents and infrastructure from flooding effects of tsunamis and typhoons (Gough, 2015). This sea wall - dubbed the ‘Great Wall of Japan’ - when finished, will be 5 stories high and is set to cost $6.8 billion. However, there have been many criticisms of this use of hard engineering methods, as opposed to soft engineering such as afforestation. Although afforestation will not stop a tsunami, it could help to slow down the speed of waves and prevent some debris being washed back out to sea (RT, 2015).

Building of the 'Great Wall of Japan'. Source

   Sea walls are fairly controversial in Japan; they are known to negatively affect oceanic wildlife by reducing biodiversity via loss of habitat (Galbraith et al., 2002), and are seen as unsightly. In some areas sea walls have been effective flood defences such as in Fundai; in others they have not. A breakwater which cost over $1 billion to construct to protect the city of Kamaishi instantly crumbled on impact during the Tohoku tsunami in 2011, killing around 1,000 people (The Economist, 2014). But, as climate change pushes sea level higher, and the frequency of natural hazards begins to increase, this may be the only viable solution that the government pursues - they are already planning to protect a further 14,000 km of coastline once the sea wall has been completed. What is your opinion on sea walls as a flood defence? Do the negative impacts to the environment outweigh the possible benefits to community safety or vice versa? Next posts will include: the Tohoku earthquake and tsunami, climate change and risk/vulnerability in Japan, and the social inequality in hazard mitigation.