Weather hazards and climate change Flashcards
(65 cards)
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
