HAZARD: A percieved natural event which has the potential to threaten both life and property.
Types of hazards:
> Climatic hazard: hurricanes, sandstorms, drought, heatwave, monsoon, global warming
> Tectonic hazard: earthquakes and volcanoes - occur due to tectonic plate movement:
Istanbul has a hazard of earthquakes because it is situated on a transform fault line
Philippines has a hazard of Mt.Pinatubo erupting because it lies on the ring of fire.
> Biological hazard: disease such as bird flu - another hazard may lead to a bio hazard
Key features of hazards making them a threat:
~ Warning time is short and onset is rapid
~ Vulnerability due to percieved economic advantage
~ Emergency response often resulting in emergency, international aid
Why people remain exposed:
~ Lack of alternatives
~ Benefits vs costs
~ Risk perception - people comforted that stats suggests more likey to be killed in car accident
~ Changing risks - low lying coastal areas were good places to live until sea live rise occured
DISASTER: A hazard becoming reality in an event that causes deaths and damage to goods/property and the environment,
Vulnerable population: susceptible to human and/or economic loss because of where they live
Hazardous geophysical event: e.g. flood, earthquake, tsunami
vulnerable population + hazardous geophysical event = DISASTER
RISK = frequency/magnitude of hazard x level of vulnerability
capacity to cope/recover
Global hazard trends
> Natural disasters are increasing in frequency - earthquakes remain constant because tectonics are not variable - generate geologically. Human activity may be a cause for increasing frequency in floods and windstorms.
> Increase in frequency has led to increase in estimated damage - bigger impact economically
> Frequency of number of people killed is decreasing - globalisation means technology and communication has advanced.
>> PARADOX: advances in us being able to report things means we'd expect an increase in deaths reported - however reports and technology means we can minimise this through prevention and predictions allowing safety measurements.
MEDC's have less victims = more advanced technology and infrastructure
LEDC's have more victims = less advanced = capacity to cope is decreasing - lack skills, education, tools and money. Owe MEDC's money - debt repayments, emergency aid, unfair trade.
Levels of vulnerability increasing: unsustainable development e.g. large population/overcrowding = building on floodplains = more likely to be flooded
Global warming and climate change: increasing frequency of climatic hazards and expanding disease carriers e.g. waterbourne cholera = biological hazard increase
Global hazard patterns / distribution
Flooding: Mississippi, East Africa,
Drought: Sahara Desert Africa, Australia, Great Plains of USA, Northeast Brazil, Meditteranean
Cyclones: South Asia
Hurricanes: East Pacific, Caribbean
Typhoons: East Asia
Earthquakes: San Francisco,
Volcanoes: Philippines, Ring of Fire
Climate change and causes
Variation in the Earth's orbit: Milankovitch theory:
The Earth's orbit changes every 96,000 years which changes the distance from the sun and changes the amount of energy recieved.
Release huge amounts of material (ash and dust) into the atmosphere blocking out sunlight which leads to a brief period of global cooling.
Greenhouse gas emission:
Excess amounts of carbon dioxide, methane etc causes too much energy to become trapped and warms up the planet. Been rising since 1750, the start of the industrial revolution.
Population growth and economic development rises carbon dioxide levels due to our reliance on fossil fuels as an energy source and when deforestation occurs or forest fires or used for agriculture.
Climate change: Natural greenhouse effect
The earth is covered by a blanket of gases which allows energy from the sun to reach the earth's surface, where some of it is converted to heat energy. Most of the heat is re-radiated towards space, but some is re-radiated towards the ground by greenhouse gases in the atmosphere.
This keeps the earth's temperature at a level necessary to support life.
Ozone: disperses harmful ultraviolet rays.
Carbon dioxide: given off when fossil fuels are burned - increased levels of carbon dioxide by 25%
Methane: rice production, burning vegetation, coal mining and livestock - levels increasing four times as fast as carbon dioxide levels.
Natrous oxide: agricultural fertilisers, burning fossil fuels, production of synthetic chemicals release this into the atmosphere which destroys ozone and thereby allows harmful ultraviolet rays into the earth's atmosphere.
Climate change: Enhanced greenhouse effect
Refers to increase in greenhouse gases due to:
> Industrialisation (1750)
> Burning of fossil fuels
Global temperature increase = greater condensation as a result of increased water vapour = increase cloud cover = more trapped heat.
Evidence for climate change
LANDSCAPE: Raised beaches and drowned valleys suggest sea levels used to be higher in the past.
ICE CORES: Bubbles given evidence of ancient trapped air. This air shows us that levels of carbon dioxide and methane now is much higher. Oxygen isotopes can also tell us what the temperature was.
TREE RINGS: Produce one new ring due to growth per year. A warmer year results in a wider ring. Patterns in these rings therefore show us changes in temperature across the years.
GHG DATA: Measurements of carbon dioxide are recorded offshore at Mauna Loa every year since the 1950s. Shows a rise around 1-2 ppm per year.
OBSERVATIONAL ECOLOGICAL: Changing migration patterns of birds and marine life
OBSERVATIONAL ENVIRONMENTAL: Vanishing ice and retreating glacier snouts
Longterm and Shorterm climate change
Climate has shifted between cold glaciers that lasted around 100,000 years and warmer interglacial periods that lasted around 10,000 years.
Ice cores > pollen analysis (preserved in sediment provides us with data about that periods weather conditions) > sea level change
Rise in temperature over the last 1000 years.
Weather records > polar ice melt > ecosystem changes
Ice fares on the River Thames when the river had frozen over during the Medieval period
Effects of climate change
Since 1975, Greenland's ice sheets melting each summer has increased by 30%
Greenland's ice cap is losing 100-150km cubed - retreating further and further than predicted.
Temperatures are rising globally - not continuous, it varies - trend is upwards
Greenland suggests the rate is getting faster and becoming expotential
Some places are warming quicker than others
Effects of climate change: worlds oceans
winds distribute heat between warmest and coldest parts. The current of warm water in the Atlantic is known as the Gulf Stream; warms the UK's climate.
North Atlantic: water is cold and saline = denser and heavier = sinks = draws warm water in from ocean surface = draws water across ocean surface from tropics = draws cold water up from ocean bottom to be warmed again = THERMOHALINE CIRCULATION. <<---- This is being disturbed. Freshwater entering Atlantic Ocean = ice melt and increase rainfall = lowers salinity = decreases density = slow down rate of ocean sinks = could turn off Atlantic Drift which supplies Europe with warm water and air.
Increasing river flow:
warmer surface air temperatures = increased river flow = increase in freshwater flowing into Arctic = slows down or shut off North Atlantic Drift.
Polar oceans: despite increase in carbon dioxide emissions the sinks aren't absorbing excess = increases levels of carbon dioxide in atmosphere due to not being absorbed = thought to increase windiness = warming tropics
The cycle of climate change
Higher temperatures (greater impact on water and food supplies) ---->
Increased evaporation (more water vapour, more glacier melt) ---->
worsening greenhouse effect - major issue of rising sea levels ---->
uncertaininity - more extreme weather, rising temperatures and changing rainfall patterns, droughts and sever storms ---->
Impacts (food insecurity, conflict over water, vulnerable people, plunged into poverty, environmental refugees) ----
Coping with climate change
Policies (strategies) reducing or preventing global warming. Involves reducing the output of carbon emissions and increase the size of greenhouse gas sinks.
E.g. congestion charges, increasing renewable energy, increasing carbon sinks - afforestation
The idea that the world has to cope with the impacts already occuring so we have to change our lifestyle to cope with a new environment.
E.g. developing drought resistant crops and managed retreat from vulnerable coasts
Adaptation usually occurs locally as its specific for that area where as mitigation can work on a local to global scale as its prevention and is policy reinforced such as the Kyoto agreement.
> Thames Barrier
>>> The Delta Project
Challenge for the future: The Stern Review
Sir Nicholas Stern focused on the impacts of global warming and the actions needed to deal with them. The debate is that if human activities is causing climate change reducing emissions is the right thing to do, and if not reducing pollution anyway is good.
Options for change:
1) Reduce consumer demand for heavily polluting goods and services
2) Make global energy supply more efficient
3) Prevent further deforestation to balance carbon emissions
4) Promote cleaner energy technology
The UK Government's reponse to Stern's options for change:
1) Set targets to reduce carbon emissions by 30% by 2020 and 60% by 2050
2) Pass laws to set carbon reduction targets, and monitor them
3) Invest in green technology, creating 100,000 new jobs
4) Create a $20 billion World Bank fund to help poor countries adjust to climate change
Challenge for the future: European Emissions Tradi
In 2007, the EU set targets for 2020 to reduce greenhouse gas emissions
It set up the ETS as a means of carbon offsetting (reducing greenhouse gas emissions)
Targets were made for every country and gave the dirtiest indutries in some of Europe's countries credits to emit certain amounts of carbon
Carbon credits: allow companies to pollute but at a cost of which they have to pay in proportion to the pollution they've produced. This is to encourage them to find other ways of producing without polluting or by polluting a little
1) cut emissions - placing a limit on amount emitted
2) polluters to pay for damage - countries can buy and sell their credits to other countries who need more or less
3) create incentives - for companies to invest in cleaner technology
Over time the ETS will reduce credits to further encourage finding cleaner technology and trading of credits
> companies moving out of Europe
> cheaper for countries to pay for credits rather than finding cleaner technology