Weather hazards and climate change Flashcards
What are the natural causes for climate change?
Volcanic activity
Solar output
Orbital changes (Milankovitch cycle)
What are the 3 sections of the Milankovitch cycle?
Eccentricity - Elliptical shape of orbit changes every 100,000 years so distance between Earth and Sun can change.
Axial tilt - Angle of tilt changes due to gravitational pull of the Moon. When tilt increases, summers get warmer and winters get colder.
Precession - Earth wobbles on its axis in a 200,000 year cycle
How does volcanic activity lead to climate change?
Volcanic aerosols reflect sunlight away, reducing global temperatures temporarily.
How does solar output lead to climate change?
Sunspots increase from minimum to maximum every 11 years. However, sunspot activity hasn’t changed in 50 years so cannot be responsible for recent climate change
What are the human causes of climate change?
Fossil fuels
Agriculture
Deforestation
How do fossil fuels contribute to climate change?
Burning fossil fuels releases CO2. Accounts for 50% of global greenhouse emissions.
How does agriculture contribute to climate change?
Accounts for 20% of global greenhouse emissions. As population grows, demand for meat and rice increases. Methane produced by cattle during digestion, and microbes in rice paddy fields.
How does deforestation contribute to climate change?
Leaves fewer trees to absorb CO2 during photosynthesis, leads to enhanced greenhouse effect.
What is evidence for climate change?
Ice cores
Ocean sediments
19cm rise in sea levels since 1900
Social effects of climate change
Increased risk of skin cancers and heat stroke as temperatures rise.
Crop yields affected: maize will decrease by 12% in South America but will increase in northern Europe and require more irrigation.
Drought reduces food and water supplies in sub-Saharan Africa.
70% of Asia at risk of flooding, causing migration and over-crowding.
Environmental effects of climate change
Coral bleaching and decline in biodiversity (Great Barrier Reef)
Sea-level rise increases flooding and coastal erosion.
Food supply will decrease for Gagnes river dolphin due to warmer rivers.
Ice melts so polar bears and seals decline in Arctic.
4 ways climate change can be mitigated
Alternative energy production
Carbon capture
Planting trees
International agreements
3 ways we can adapt to climate change
Changes in agricultural systems
Managing water supplies
Reducing risk
How can alternative energy production mitigate climate change?
Reduces greenhouse gas emissions compared to fossil fuels. Becoming cheaper and more competitive, yet still expensive and unreliable.
How can carbon capture mitigate climate change?
Takes CO2 from emission sources and stores it underground. Impermeable ‘cap rock’ prevents it from escaping. Can capture up to 90% of CO2 and could provide 10-50% of world’s total carbon mitigation until 2100.
However, it is expensive, unclear if CO2 would remain captured and doesn’t promote renewable energy.
How does planting trees mitigate climate change?
Removes CO2 and produces oxygen through photosynthesis. Could increase forest carbon storage by 28%. Trees are used as habitats. However, land may be limited and biodiversity is reduced when only one species of tree is planted.
How do international agreements mitigate climate change?
Encourages countries to take responsibility for reducing CO2 emissions. Targets more likely to be met when legally binding (Paris 2015). Financial support offered to LICs. However, targets may not be achieved and some countries are more responsible for climate change than others.
How can changes in agricultural systems adapt to climate change?
Needed to deal with changing rainfall, temperature patterns, distribution of pests and extreme weather. Production needs to move location, irrigation needed, changes to crops and varieties. However, these adaptations are hardest for poor farmers, who are the most affected.
How can managing water supplies adapt to climate change?
Ensures populations can adapt to changing rainfall patterns. In London, demand is reduced by using water-efficient devices and increasing supply by opening desalination plants. Water security may be threatened in areas of water deficit.
How can reducing risk adapt to climate change?
Constructing defences (Thames barrier or mangrove forests)
Raising properties on stilts.
Relocating people.
What are trade winds?
Winds flow from areas of high to low pressure which means at ground level winds flow back towards the equator.
What is the Coriolis effect?
The impact that the Earth’s spinning has on air.
It causes air to bend.
It is the reason tropical storms develop a spinning structure
Describe the Hadley cell
Air at the equator is heated so rises in low pressure conditions. Air flows towards North and South poles. As warm air rises it cools and condenses, bringing cloud and rain. Air sinks at 30o North and South of the Equator under high pressure. High pressure weather brings dry and clear skies.
Where are tropical storms found?
5 and 30 degrees north and south of the equator
Structure of a hurricane
Eye = calm
Eye wall = wind
Rainbands = rain and tornados
State the conditions needed for tropical storms
Low latitudes (5 and 30 degrees north and south of the equator)
Oceans with temperatures above 27oC
Ocean depth 60-70m
Summer and Autumn
Low wind shear
Why do tropical storms occur at low latitudes (5 and 30 degrees N and S of the equator)?
Temperatures are higher so sea and air are heated more quickly. Low air pressure and air rises. Coriolis effect is strong enough for tropical storms to spin.
Why do tropical storms occur at specific sea conditions?
Provides heat and moisture so warm air rises rapidly.
Why do tropical storms occur between summer and autumn?
Warmest seasons, warmer air rises rapidly creating low pressure conditions
Why do tropical storms occur with low wind shear?
Constant wind means clouds can rise to high levels without being torn apart.
Under what atmospheric conditions does warm air rise rapidly to form a tropical storm?
Low-pressure conditions
What causes the rising air to spin around the calm central eye of a tropical storm?
The Coriolis effect
What type of clouds are formed when rising air cools and condenses in a tropical storm?
Cumulonimbus clouds
What weather condition is associated with the formation of cumulonimbus clouds in tropical storms?
Torrential rainfall
Describe the sequence of formation of tropical storms
Air is heated above surface of warm tropical oceans
Warm air rises rapidly in low-pressure
Strong winds form as rising air draws up more air and moisture
Rising air spins around a calm central eye of the storm due to the Coriolis effect
Rising air cools, condenses forming large cumulonimbus clouds and torrential rainfall
Heat given off as it cools, powering storm
Cold air sinks in the eye so it is clear, dry and calmer
Tropical storm travels across ocean with prevailing wind
On meeting land, loses source of heat and moisture so loses power
How will climate change affect the distribution of tropical storms?
More in areas such as the South Atlantic and subtropics as sea surface temperatures increase.
How will climate change affect the frequency of tropical storms?
Overall - Remain the same or decrease
Frequency of category 4 and 5 storms will increase.
Frequency of category 1,2,3 storms will decrease
How will climate change affect the intensity of tropical storms?
Number of category 4 and 5 storms is increasing.
Every 1 degree increase in sea surface temperature results in 3-5% increase in wind speed.
Where was typhoon Haiyan?
Philippines
When was typhoon Haiyan?
8 November 2013
How many people died due to typhoon Haiyan?
6190
What % of Tacloban was destroyed due to Typhoon Haiyan?
90%
Primary social effects of Typhoon Haiyan
50% of houses destroyed
4.1 million made homeless
6190 people died
Primary economic effects of Typhoon Haiyan
$12 billion of damage
UN stated that 75% of farmers and fishermen lost their incomes
Damage to rice cost $53 million
Primary environmental effects of Typhoon Haiyan
800,000 litre oil leak at Estancia
400mm of rainfall caused flooding
1.1 million tonnes of crops destroyed
Secondary social effects of Typhoon Haiyan
8 deaths in a stampede as survivors fought for rice supplies
Infection and diseases spread due to contaminated surface and groundwater
Power supplies cut off, up to a month in some areas
School destroyed, affecting people’s education
Landslides blocked roads, preventing aid from reaching people
Secondary economic effects of Typhoon Haiyan?
Fishing industry disrupted due to oil spill, contaminating fishing waters
Looting was rife due to lack of food and supplies
Airport badly damaged and roads blocked by debris
By 2014, rice prices had risen by 12%
Secondary environmental effects of Typhoon Haiyan
10 hectares of mangroves contaminated by oil barge leak
Flooding caused landslides
Immediate response to Typhoon Haiyan
Authorities evacuated 800,00 people, many going to Tacloban indoor stadium
1200 evacuation centre set up
Within two weeks, 1 million food packs and 250,000 litres of water were distributed
Long-term responses to Typhoon Haiyan
$1.5 billion pledged in foreign aid
July 2014, government introduced ‘Build Back Better’ recovery plan
‘Cash for work’ paid people to clear debris and rebuild the city
Oxfam replaced fishing boats
New storm surge warning system installed
How can tropical storms be monitored?
Satellites monitor cloud patterns
Global Precipitation Measurement satellite monitors high-altitude rainclouds every 3 hours
NASA monitors weather patterns across the Atlantic using Global Hawk drones
How can tropical storms be predicted?
Supercomputers, developed by NOAA, give five days’ warning and a location within 400km.
National Hurricane Centre (Florida) use ‘track cones’, with 70% of tropical storms occuring in predicted cone.
Protection against tropical storms
‘No build zones’ in low-lying areas.
Reinforcing buildings (hurricane straps, storm shutters, removing trees)
Coastal flood defences such as levees and floodwalls.
Planning for tropical storms
Preparing disaster supply kits.
Ensure vehicles are fuelled
Knowing where evacuation shelters are
What are 4 types of extreme weather faced in the UK?
Flooding
Droughts and heatwaves
Storm events
Extremes of cold weather
What direction do tropical storms spin the northern hemisphere?
Anticlockwise
What direction do tropical storms spin the southern hemisphere?
clockwise
When was the Beast from the East?
25 February 2018
Causes of the beast from the east
Change to Northern polar jet stream as a result of increased temperatures over the arctic, causing it to twist direction, drawing in cold air to the UK from the east.
Moisture picked up by air brought snow.
Social impacts of the beast from the east
A man died after being pulled from a frozen lake, along with 3 other reported deaths.
Major accidents on the A1 in Northumberland
Hospitals in Glasgow asked staff who can walk to work to cover shifts
Shelves in supermarkets stripped of bread, milk, soup.
Economic impacts of the beast from the east
BA cancelled hundreds of short-haul flights from Heathrow
AA estimated that collisions on Britain’s roads cost £10 million in insurance
Environmental impacts of the beast from the east
Snow drifts were as high as 7m in places
Reduced insect populations due to low temperatures
Use of gas and electricity doubled, causing higher CO2 levels
Sugarbeet crops damaged
How was the beast from the east managed?
Public Health England urged people to plan ahead to ensure they had enough food and medicine
Army and RAF personnel were called in to ferry health workers through blocked areas in Scotland.
Councils sent out gritters and snow ploughs to clear roads
Evidence to show that temperatures have become more extreme in the UK
UK temps have increased by 1oC since 1980s.
Highest temp in UK was 38.5 in August 2003
December 2010 was coldest on record for 100 years. Warmest April was 2011.
Evidence to show that rainfall has become more extreme in the UK
Highest 2 day record of rainfall (405mm) in 2015.
Serious flooding has become more frequent in winter e.g. Cumbria 2009, heaviest rainfall on record.
Highest monthly rainfall of 1,396 mm in 2015.
