EXAM Q'S A-LEVEL BEFORE 2016 PHYSICAL Flashcards
Describe the global distribution of tropical cyclones
Most intense cyclones are north of equator, around North America and North America regions. Below the equator are minor cyclones, only focused on Australia. This is linked to ENSO cycles of La Niña and El Niño.
El Niño= ocean temp hotter
La Niña= ocean temp cooler
Reasons for the distribution of tropical cyclones
A tropical cyclone=an intense low pressure weather system. They all occur in a band that lies roughly between tropics of Cancer and Capricorn.
Distribution is controlled by the places where sea temps rise above 27 degrees
CAUSES=hot air rises, taking a lot of water vapour with it. As water vapour rises up it cools to form big cumulus clouds —> This creates low pressure at sea level
Describe 2 recent environmental changes that provide evidence for global warming
1- Melting ice caps in Arctic + extinction of arctic animals due to less ice cover, resulting in a loss of habitat
2- Extreme events, the no. Of record high temps in US has been increasing + ocean acidification, since beginning of industrial revolution, acidity of surface ocean waters has incr 30%
Explain why global warming and El Niño events may lead to increasing natural hazards (15 marks)
El Niño leads to unusually warm water in the Pacific Ocean across central and east.
•Typically El Niño effects are likely to develop over NA during upcoming winter season
—>Includes warmer than average temps over Western and Central Canada + USA —> whereas wetter conditions over portions of Gulf coast and Florida
•Warming of oceans=water expansion + flooding + more stronger storms
•Also, warmer surface water dissipates more readily into vapour, making it easier for small ocean storms to escalate into large systems.—> this can harm marine ecosystems like coral reefs and forests.
•Increased storms means less recovery
•Warmer sea temp means spread of invasive species and marine diseases
•Warm seas=melting ice shelves + interrupting oceans conveyer belt(the system for regulating earth’s temp)
Explain the environmental problems of oil exploration
- Deep water exploration (e.g Gulf of Mexico) - 49m total barrels of crude oil was released - affects coral + food chains
- Tar sands wreaks havoc on Alberta’s boreal forest. Boreal wetland ecosystems trap massive amounts of carbon and is important for atmosphere health. Used 2.4 barrels of freshwater for every barrel produced
- Amazon: pipeline can fragment habitats. Can lead to soil + aquatic pollution
Explain how human activities have contributed to condition of ecosystem goods and services
GOODS: Food, water, fuels, timber
SERVICES: Water supply, air purification, natural recycling of waste, soil formation, pollination.
HUMAN: Land-use change, including agric intensification + urbanisation, climate change
•Natural vegetation lost to crops or production of biofuels or animals
•Soil erosion can cause rivers to become silted up + lack of shade and moisture in soil can lead to desertification (infertile soil)
Evaluate value of sustainable + integrated approaches to coastal management (10 marks)
•Sustainable approaches=tend to be more soft engineering
—>Dune regeneration(absorbs waves)
•Marshland can be created via coastal realignment (Managed retreat) which involves breaking an existing defence and allowing the sea to flood the land behind. Vegetation will colonise.
•Mangrove replanting. These swamps act as a buffer, reducing wave impact and severity of floods + tsunamis.
Why are some EQ’s more common in specific parts of the world?
- In areas with major plate boundaries, often destructive, e.g. San Andreas fault line, EQ’s are more common and strongly felt. Due to collisions of the 2 plates moving together, sends out seismic waves.
- Some EQ’s occur in sea where dense oceanic is subducted under continental
- Most volcanoes, like Hawaii, occur on interior at “Hotspots”
What is meant by disaster hotspot?
Where EQ’s of a high magnitude (+7) occur more frequently, at destructive plate margins. This could be in oceans + surrounding islands could be affected by tsunamis, as seismic waves radiate out from epicentre.
•Disaster hotspots are multiple hazard zones with high vulnerability to the size, density and poverty of population.
•Cali is susceptible to EQ’s as it lies of plate boundary (Pacific + NA plate)
Describe 2 ecological impacts of climate change in Arctic
1- Possible extinction of animals, losses in food chains, less ice cover means seals and polar bears can’t find food
2- Melting ice sheets can increase sea level, leads to more submergence
(As snow + ice melts, ability of Arctic to reflect heat back to space is reduced, accelerating global warming - Reduced ALBEDO)
(A warmer Arctic could half the Gulf Stream which brings warmer water + weather to N.W Europe)
Explain why droughts can have severe impacts on people and environment (10 marks)
- Wildfires can break out, destroying hectares of forest. Forests act as lungs of earth and regulate CO2 levels.
- They also act as water filters, collecting + storing water + recharging underground acquifiers + Many medicines have been discovered
- Groundwater levels can reach new lows, with Springs + wetlands drying up
Explain the increasing frequency of hydro-meteorological hazards (cyclones, storms, droughts, floods)
•Floods unceasing did to melting ice + temperature
•El Niño—>which is caused every few years when a current of water in Pacific, off N.W coast of SA becomes warmer during winter than normal
—>Countries such as AUS or AFRICA can suffer flood + drought
—>Can also cause winter temp to fall upon N.A + can increase winter rainfall in Europe
•Floods + windstorms increasing due to increased warming of earth causes warm air to rise, creating conversion currents + hurricanes = Floods
•Increased temp=incr evaporation=incr precip
Possible implications for climate + hydrological cycle if 2 degree temp rise
CLIMATE-
•Atlantic + S.Ocean thermohaline circulation may be weak, altering transfer of heat by oceans
•Precip will incr in higher latitudes + decrease in lower latitudes, more common in tropics+subtropics
•Temp + tropical zones may experience stronger storm activity due to more heat energy + moisture
ECOSYSTEMS-
•10% landscapes face extinction
•Biodiversity affected as habitats shift poleward or into deeper ocean waters or high altitudes. In N.Brazil=lower rainfall + soil moisture = cause changes to soil+oxygen —> reducing biodiversity
•Tundra biome affected by thawing permafrost. Marine diversity loss
HYDROLOGICAL-
•Rivers day up. Shift in subtropical high-pressure areas northwards will cause 20-30% decrease in water availability in Med climate zones
•Small glaciers will disappear, decreasing river discharges
