Monday, 25 November 2013

What made Typhoon Haiyan so Devastating?

Typhoon Haiyan, which devastated the Philippines in November, is one of the strongest storms ever recorded at landfall. So how did this typhoon come about?

Tropical storms (hurricanes, cyclones or typhoons, depending which part of the world you're in) can only occur when conditions are just right. These are the ingredients of a typhoon:

1.    Warm ocean water (at least 27C to a depth of 50m)
2.    At least 5 degrees/ 500km away from the equator where Corioli's force is strong enough to cause rotation (hurricanes rotate ACW in the northern hemisphere and CW in the south)
3.    An unstable/steep lapse rate (the change in temperature with height) to encourage convection
4.    Low vertical wind shear (the change in wind speed with height), which could prevent convection and disrupt the structure of the storm
5.    High humidity in the mid-troposphere (about 5km up)
6.    A tropical/easterly wave/disturbance (an area of low pressure with clouds and thunderstorms, around 100 develop every year but only 10 meet the right conditions to turn into a hurricane).

Even when all these conditions are met, a hurricane may still not develop. However, if it does, this is what happens:

But why was Typhoon Haiyan so devastating, what made it one of the strongest typhoons ever recorded?

Well, to start with a single hurricane vary in size and intensity, when they reach land they are often not at their greatest strength  (Katrina reached Category 5 on the Saffir-Simpson Hurricane Scale when she passed over the Gulf of Mexico but had fallen to a 3/4 by the time she reached Louisiana). Also, when they reach land and move away from their fuel source of warm water they quickly lose some of their strength.

However, you can see from the image below, it just so happened that when Typhoon Haiyan hit the Philippines it had reached it's peak intensity: a Category 5 with sustained wind speeds up to 200mph. Haiyan was able to reach this intensity because she formed over a wide expanse of open ocean with perfect hurricane conditions; one is that there was very little wind shear in the area to disrupt the convectional air flows and rotating winds.

The typhoon also had a plentiful supply of warm water, not just within the first 50m, but unusually (some have linked this to anthropogenically influenced climate change) the ocean was warm enough for hurricane formation down to a depth of 100m! Once the storm whipped up the top layer of water there was still a plentiful supply of heat below giving the typhoon more and more energy. Check out the map below:

Not only had this typhoon reached it's full strength when it hit the Leyte and Samar provinces of the Philippines but it brought a huge storm surge with it, which was magnified by a deadly combination of wind direction and coastal topography. Along most of the eastern side of the Philippines the ocean is very deep, making storm surges unlikely as waves need progressively shallow water to build any height. However, the orientation of Haiyan as she hit land meant that north-westerly winds drove the storm surge into San Pedro Bay which, although mostly deep water, becomes much shallower and also narrower to the north. The bay acted liked a giant funnel, causing the tsunami-like surge to reach 5 metres in height.

So far, the death toll is estimated to be over 5000, 600 000 are homeless, while the economic costs to the Philippines range from $5-14 billion. The super-strength and huge size of this storm (estimates of her diameter range from 6-800km) and the devastating surge it brought with it were bound to have a severe and lasting impact. But maybe if the archipelago has been better prepared the damage and loss of life could have been mitigated to some extent. Although some preparations were made (e.g. the evacuation of 1 million people and government announcements telling people to prepare), it was no where near enough. Firstly no one was expecting the storm surge so, for example in Tacloban several thousand people took shelter in a big indoor 'stormproof' stadium. Sure enough, the roof stayed on, but people were killed by the storm surge which flooded through the bottom.

The typhoon also hit one of the poorest regions of the Philippines, where people lived in flimsy make-shift shanty-towns and even properly built structures do not conform to an sort of typhoon proof regulations as they surely should do, being in a high risk area. Low levels of education and a corresponding lack of appropriate language grading by the authorities also meant that despite being warned about an impending storm surge many residents did not realise what this meant so failed to take even simple potentially life saving measures such as going upstairs in the stadium instead of staying on the ground floor until it was too late. On top of all this, the Philippines has a very high population density, over 300 people per square km, compared to around 250 in the UK, putting a huge number of people at risk.

In conclusion, a combination of physical and human factors, summarised below, made Haiyan one of the worst natural disasters we've seen in a long time.

  • Open ocean with no land masses
  • Very little wind shear
  • Very warm water down to 100m
  • Made landfall at full strength
  • Funnelling effect in San Pedro Bay
  • Lack of preparation
  • High population density

Lets just hope that some lessons are learned for next time. In the mean time, please donate generously to help the survivors. You can do so here.

Finally, check out this page which has some great maps explaining the path and impact of the typhoon as well as some before and after satellite photos:


Sunday, 24 November 2013

Level 3/4 Separatism Essay with Examiner Comments

Analyse the reasons for separatism within and/or across national boundaries and discuss its consequences (40 marks)

Separatism is an attempt by a regional group within a country or across the borders of one or more countries, to gain more political control from central governments over the areas in which they live. There are many different reasons for why separatism occurs around the world, these can include: the feeling of being economically depressed compared to other areas within the same country; the fact that some people feel that they are in a peripheral location to economic and political care; the desire to protect and build upon a minority language or religion and the feeling or being mistreated due to being an ethnic minority (e.g. the Tamil Tigers in Sri Lanka). Separatism can lead to a wide range of consequences that range from the collapse of governments and civil wars to, more political disputes and peaceful protests. Separatism does not have to be aggressive.

Good introduction to the topic, defines separatism and outlines the causes and consequences. It would be good to mention some real examples too, for example the case studies used in the essay could have been mentioned in appropriate places - see example in italics.

The Sri Lankan civil war is a prime example of where Separatism has led to aggressive consequences, in this case the acts of the Tamil Tigers (a separatist group) led to a civil war that spanned over three decades. The Sri Lankan civil war was fundamentally caused by ethnic discrimination between the ethnic majority Sinhalese and the Tamil minority that populated the north and northeast of the island.  When the British owned Sri Lanka they turned the country into the tea making capital of the world and brought with them a vast amount of wealth and benefits to certain groups. These certain groups where the Hindu Tamils of Sri Lanka and India; furthermore when the British gave Sri Lanka its independence it did not take long for tensions to arise. With the minority Tamils not gaining any political power when Sri Lanka gained its Independence, they were repeatedly repressed and eventually leading a group known as the Tamil Tigers to start an insurgency that would turn into a civil war (1983-2009). This conflict had many consequences. One of which was the massive amount of civilian casualties that occur during many attacks on both sides. During the entire war it is estimated that up to 70% of the 80,000-100,000 people that died in the war were actually civilian casualties. This huge social impact was just accompanied by war crimes such as rape and torture throughout the war and none more so at the end when the government shelled a hospital island and forced the fleeing Tamil civilians into imprisonment camps. 

Detailed knowledge builds a sense of place for the first case study, evidence of critical understanding and use of specialise vocabulary shown.

On the other hand it was not just the Sri Lankan government that were behind social impacts; the Tamils found themselves being listed as a terrorist organisation by 34 countries due to the suicide bombings they carried out. One of which was outside the world trade centre in the capital city of Colombo which killed 39 people and meant that many were scared to go about their day to day lives. These bombings also led to increased security in main towns and cities and made in increasingly harder for civilians to live a normal life.  However over the course of the war it there were not just social consequences; one environmental impact was the destruction of over 5 million tress. These trees used to supply wildlife with homes and shelters and thus a negative feedback system is being observed in some unique species within different regions in the north of the country. The destruction of these 5 million trees has not only had severe environmental impacts; it has also led to more farmers suffering from poverty as they are missing out of the economic benefits of the forest areas that so many relied on. Unfortunately for the Sri Lankan people and government, the poverty and negative feedback for the destructions of so many trees is not the only or worse economic impact due to the civil war. One of the worst impacts is the fact that the government is still spending up to 30% of its yearly budget paying for damages and the cost of the war (the war is thought to have cost the government $200 billion).

Continued use of detailed knowledge and critical understanding of this knowledge. Synopticity shown in the range of impacts that are mentioned (social/environmental/economic). Environmental impacts could be stronger - negative feedback system is not explained? 'Unique species' should be more specific - does the candidate mean endangered or endemic? Also some spag inaccuracies.

Another example of where Separatism has led to clashes is between the Kurds and the Turkish government (Turkish in particular). In this case the Kurdish people (an ethnic group by their own right, with their own language and traditions) do not have a nation and partition as well as fight for their own country of Kurdistan. The main issue here being that this Kurdistan would take a large chunk out of Turkey and some land out of countries such as Iran and Iraq. This and the fact that the Kurds have their own language and beliefs has led to them being continually persecuted and oppressed. A fine example of where war crimes have been committed against the Kurds is through a genocide by Saddam Hussein in the 90’s.

Second case study briefly outlined with some specific knowledge. Could be improved with more detail. The reason for using this case study is slightly unclear - what does it add to the essay? What point is it used to illustrate?

On the other hand, not all acts of separatism end up leading to aggressive conflicts. The partition by some people and governmental officials in Scotland, which includes the use of protests and voting, is a prime example of where separatism is being resolved peacefully. There are some within Scotland that believe that the only way to preserve and save their native language of Gaelic, is to leave the UK and become their own separate nations. To try and stop this from happening (many think due to the fact that there is oil off of the north coast of Scotland that the UK need) the English government offers financial and social support. This leads to clashes as the British people believe that it is unfair that for instance they have to pay for university tuition fees and the Scottish students too.

Use of 3rd case study this time backs up a point made - that the consequences of separatism are not always violent. This shows critical understanding of the issue. Somewhat unclear at the end. 

To conclude, it is easy to show how badly separatism can impact of both society, the environment and the economy in a country and across borders (Scotland). However in more cases than not it seems that it leads to violence as people struggle to have their voices listened to and thus lash out aggressively. This can be shown by the fact that Scotland and the UK have not had violent clashes, as their voices are being listened to and acknowledged.  I would also say that when looking at the Kurds and Sri Lankan civil war, it seems to be that the main consequences of separatism tend to be social. This in some ways could be said to be ironic and in many cases the causes of the Separatism in the first place is social issues. Finally is would seem that when looking at Scotland compared to example such as Sri Lanka; when there is a well-established government overviewing the whole scenario, it tends not to lead to aggression and thus the consequences are far less.

Strong conclusion discussing the consequences of separatism, however does not mention causes.
Overall the candidate has shown evidence of detailed knowledge, frequent critical understanding and some ability to synthesise a range of information. The case studies are rather imbalanced and the quality of the argument, whilst strong in places, could be structured a bit better, e.g. redundant use of Kurdish case study. However, overall a sound essay, high level 3 to low level 4.

1109 words - about the right length to write in an hour, maybe slightly too long.

By Sam Evatt

Monday, 18 November 2013

Level 3/4 Separatism Essay

Analyse the reasons for separatism within and/or across national boundaries and discuss its consequences (40 marks)

Separatism is an attempt by a regional group within a country or across the borders of one or more countries, to gain more political control from central governments over the areas in which they live. There are many different reasons for why separatism occurs around the world, these can include:

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