climate change Flashcards
what is global atmospheric circulation?
- transfer of heat from the equator to the poles by the movement of air
- air moves due to the differences in air pressure
- the GAC system is divided into loops (called cells)
what does each cell have?
- warm rising air that creates a low pressure belt
- cool sinking air that creates a high pressure belt
- each hemisphere has three cells
what do tropical storms need to develop?
- tropical storms develop between 5 and 30° north and south of the equator when:
- sea temp is 27° or higher
- wind shear between higher and lower parts of the atmosphere is low
how does a tropical storm form?
- warm surface water evaporates, rises and condenses into clouds - this releases huge amounts of energy, producing powerful storms
- low wind shear prevents clouds from breaking up as they rise, so storm stays intact
- easterly winds near the equator move tropical storms to the west
why does a storm spin?
due to the Coriolis effect
what happens when a storm moves over the ocean?
energy from the warm water strengthens the storm - so wind speeds increase
when do storms lose strength?
when they move over land or cooler water - as energy supply from water is cut off
what are the characteristics of the eye (centre) of a storm?
- up to 50km across
- caused by descending air
- very low pressure, light winds, no clouds
- high temperature
what are the characteristics of the eyewall (surrounds eye) of a storm?
- spiralling rising air
- very strong winds
- storm clouds, torrential rain
- low temperature
what is towards the edges of the storm?
- wind speed falls
- clouds become smaller and more scattered
- rain becomes less intense
- temperature increases
Typhoon Haiyan primary effects?
- 6,300 dead - most drowned in storm surge
- 600,000 people displaced
- 90% of Tacloban city destroyed
typhoon haiyan secondary effects?
- 6 million left with no job
- lack of clean water lead to outbreaks of disease
- power supplies cut off in some areas for a month
typhoon haiyan immediate responses?
- fishermen warned not to go to sea
- the red cross delivered basic food aid - inc. rice, canned food and oil
- 1,200 evacuation centres to help homeless
typhoon haiyan long-term responses?
- charities built storm-resistant houses for those who lost their homes
- mangrove forests being planted to act as a natural flood defence
- UN appealed for over $300 million to help fund rebuilding and relief
how can climate change affect tropical storms?
global average sea surface temperatures have risen + are expected to rise more
how can climate change affect tropical storms’ frequency?
- oceans will stay at 27° C or higher for longer - so longer period when they can form
- may mean more storms each year
how can climate change affect the distribution of tropical storms?
- as average ocean temperature rises - more of the world’s oceans could be above 27° C
- meaning TS’s can form in areas that haven’t experienced them before
how can climate change affect the intensity of tropical storms?
- higher sea surface temperatures are likely to result in more evaporation + increased cloud formation
- means more energy is released
- could mean storms more powerful
how can prediction reduce the effects of tropical storms?
predicting where and when a TS will happen gives people time to evacuate
how can monitoring reduce the effects of tropical storms?
computer models can be used to calculate a storm’s predicted path
how can planning reduce the effects of tropical storms?
- future developments can avoid high-risk areas
- emergency services can prepare
- governments can plan evacuation routes
how can protection reduce the effects of tropical storms?
- buildings can be designed to withstand tropical storms
- buildings can be built on stilts to be safe from floodwater
- flood defences can be built along rivers
what is the impact of strong winds?
- can damage properties
- can disrupt transport
what is the impact of heavy rainfall?
- recovery from flooding can cost millions of pounds
- this can cause flooding - can damage homes + drown people
what is the impact of snow and ice?
- can cause injuries due to slipping
- schools and businesses can be forced to shut
what is the impact of drought?
- water supplies can run low - causing economic impacts like crop failure
- rules to conserve water have to be introduced
what is the impact of thunderstorms?
- lightening can cause fires which can kill people
- can destroy the environment
what is the impact of heatwaves?
- can cause heat exhaustion - which can kill people
- can melt roads and buckling rails - disruption to transport
what is evidence that the weather is becoming more extreme in the UK?
- summer 2018 - one of the hottest summers since records began
- extreme cold events seem to be more frequent
- December 2010 - coldest month for over 100 years
- major flooding events become more frequent
- December 2015 - wettest month ever recorded
what are the causes of the Boscastle flood (2004)?
- 89mm of rain fell in an hour
- narrow river channels in the village itself
- the ground was saturated from previous rain so water flowed quickly into the river valency
what are the social impacts of the Boscastle flood?
- cars and vans were washed into the sea
- loss of communications
- hundreds had to evacuate from their homes
what are the environmental impacts of the Boscastle flood?
damage to local wildlife habitats
what are the economic impacts of the Boscastle flood?
- loss of businesses
- loss of tourism - which was major source of income for area
what were management strategies to reduce the risk of Boscastle flood happening again?
- £4.5 million has been spent on flood defence scheme
- river channel has been made deeper and wider to hold more water
- Boscastle car park has been raised + given a permeable surface
what is the quaternary period?
- most recent geological time period
- period of time from 2.6 million years ago to present day
