Weather Hazards and Climate Flashcards
Natural causes of climate change
Solar variation:
the amount of energy the sun gives out varies
when the sun gives out more energy- we experience an interglacial
Volcanism
when a volcano erupts, ash is emitted
the ash blocks the sun causing a volcanic winter/glacial
Eccentricity
the orbit of the earth changes every about 100,000 years
if it’s more circular there will be an interglacial
if it’s more elliptical, there will be a glacial
Axial tilt
angle of tilt changes every 40,000 years
sometimes earth is tilted further away from the sun, making the difference in seasons much more pronounced
e.g. warmer summers colder winters
Tree rings
- these are lines inside the tree for every year the tree has been alive
- if a tree ring is wider- that mean the year was more wet
- if the tree ring was thinner- that indicates that it was a drier year
- cut the tree and deduce the weather patterns from years ago
Historical documents
- cave paintings in Jordan and the Sahara desert show people who appear to be swimming and elephants
- this would be possible in the current climate
- shows change
human graves in greenland are buried two metres deep
- which would not be possible to dig through the hard ice
- this suggests that the climate in greenland was warmer than today
- fairs on the river thames means that the river would freeze over
- today this would not be possible due to our temperate climate
Ice cores
- an ice core is a cylinder of ice from an ice sheet
- more snow falls and it compacts to form ice
- different gases get trapped between the layers of snow ice
- if more carbon dioxide is trapped in the ice core, ot means the climate was warmer
- if less is trapped, it was cooler
Natural greenhouse effect
- heat energy from the sun passes through the atmosphere and heats up the earth
- much of this energy is radiated back into space and some of it is trapped in the earth
- greenhouse gases trap heat allowing the earth to sustain life
Enhanced greenhouse effect
more greenhosue gases in the atmosphere
less heat raidated back into space
more heat trapped on earth causing global temperatures to rise
how has industry increased the amount of greenhouse gases in the atmosphere
- rising demand for consumer goods with rising population
- increases production
- burning more fossil fuels
- greenhouse gases released
how has farming increased the amount of greenhouse gases in the atmosphere
- population growth so higher food demand
- meat consumption increased due to western diets
- mechanisation of farming so more fuel is burnt
- cattle and rice production in flooded paddy fields releases lots of methane
how has energy increased the amount of greenhouse gases in the atmosphere
- demand for electricity grwoing due to new technology
- more fossil fuels burnt
- more greenhouse gases
negative impacts of climate change
- crop yield decreased due to decreased photosynthesis
- so plants won’t be able to produce as much as energy to survive
- large section of the population will suffer from malnutrition
how will climate change impact the maldive and list a social, economic and environmental impact of sea level rise
land based ice in places such as the antarctica will melt and add water to the oceans
- warm water occupies a larger volume than cold water- so oceans will expand in volume
- the highest point on the maldives is only 2.4 metres above sea level
- global sea levels are expected to rise by 20cm to 2 metre
- tourism industry in the maldives is at risk as international airports are built within 50 metres of the coastline
social: higher sea levels and regular storms lead to periodic flooding of coastal areas. in 2007 1600 people had to be evacuated
economic: the key attractions of beaches and coral reefs will become inaccesible so there will be a loss of employment in tourism. cost of evacuation and rehousing will continue to increase
environmental: ground water supplies are contaminated with sea water flowing into islands. soil is contaminated. temperature increase in the surrounding oceans may lead to bleaching and deaths of coral reefs
what are increasing temperatures doing to many glaciers? what will the results of this be short and long term? and on a global level?
they are retreating, becoming smaller and ice sheets are thinning
in the short term: melting of high mountain glaciers can lead to the flooding of local areas
in the long term: there will a smaller volume of ice available in the glacier
so there will be water shortages because less water is produced by the glacier on a daily basis
on a global level: melting ice sheets will add more water to the oceans so sea levels will rise
What type of rainfall is common in the UK? How does it form?
frontal rainfall
-meeting of major air masses; cool air from the north and warmer air from the south
Medieval Warm Period
-increased solar activity and less volcanic activity
950-1100
grape vines were able to be grown
milder winters and greater availability for food meant that more people lived
Little Ice Age
1600-1850
Increased volcanic activity and decreased solar activity
thames froze over
What influences UK climate
PREVAILING WIND
- travelled over large expanses of warm ocean, so air is warm and moist
- reaches western areas first and releases moisture as rain
- so eastern side is relatively drier
MARITIME INFLUENCE
- UK is surrounded by sea
- air that reaches us contains a large amount of moisture
- rainfall all year
NORTH ATLANTIC DRIFT
- this warm ocean current brings in warm water to the north of the UK from the Gulf of Mexico
- makes our winters warmer and our climate is warmer than would be expected for the latitude
CIRCULATION CELLS
- UK located near the boundary between the Northern Ferrel cell and the Polar cell
- warm air from the south and cooler air from the north meet, leading to depositions and unsettled weather
ALTITUDE
- the higher the altitude of an area, the cooler (1 degree celcius for 100 metres)
- air is forced to rise over high land
- it is cooled causing more moisture in the air to condense and fall as precipitation on the hill tops
- e.g. Scafell Pike averages 178 days of rainfall per year
Cyclones
intense rotating storm with winds exceeding 119km/hour
they often are 400km wide and 10km high
When are cyclones most likely to form?
intense rotating storm with winds exceeding 119km/hour
they often are 400km wide and 10km high
What are the four conditions needed for a cyclone to form?
1 a source of warm, moist air from tropical oceans with sea surface temperatures in excess of 27 degrees celcius
2 the warm water must be at least 70m deep
3 winds converging at the ocean surface causing the air to rise
4 spin induced by the rotation of the earth- they are not able to form within 500km within the equator because the force is not large enough
How does a tropical cyclone become stronger?
the further it travels down the ocean, the more moisture it collects, increasing the strength
How does a tropical cyclone become weaker and slower?
- when the cyclone reaches land, it is cut off from its energy source- the warm tropical waters
- it can no longer extract heat from the ocean so loses strength and slows
Why do scientists track tropical cyclones?
-so that preparations can be made for potential landfall locations
How do scientists keep track of tropical cyclones?
-the use of satellite imagery and statistical modelling
What are the impacts of tropical cyclones?
HIGH WINDS at least 119km/h air moves very quickly -trees unprotected -damage to houses and buildings -injury and death
INTENSE RAINFALL- the low pressure system leads to high rainfall
- damage to crops
- drowning
STORM SURGES -winds force water towards land with great force
- erosion of beaches and habitats
- coastal defences damages
- farmland contaminated with saltwater
COASTAL FLOODING- areas covered in water
- people and property at risk
- farming damaged
- toursim affected
- litter on coast
- damage through saltwater
LANDSLIDES- soil can become saturated so it is heavy, leading to mass movement
- settlements are damaged
- river flooding
