GCSE AQA Geography Section A: Climate Change

How does ice and sediment prove evidence for climate change?

scientists drill into layered ice sheets to get long cores of ice to analyse gases trapped which determines past temperature

How do tree rings prove evidence for climate change?

scientists take cores and count the rings to find the age of a tree, the thickness of each ring shows what the climate was like (thicker=warmer)

How does pollen analysis prove evidence of climate change?

scientists identify + date preserved pollen showing species that lived at the time + scientists know conditions that plants live in now, preserved pollen from similar plants shows similar climate conditions

How does temperature prove evidence for climate change?

since 1850's, global temperatures measured accurately using thermometers + historical records like harvest dates can extend the record of climate change further back

How are orbital changes a natural cause of climate change?

• affects amount of solar radiation the Earth receives - more energy = more warming

• Earth closer to sun = it's hotter

• Earth further away from sun = it's colder

• happens every 100,000 years

How is solar activity a natural cause of climate change?

• the sun doesn't burn consistently

• more sunspots = more solar radiation resulting in higher temps

• less sunspots = less solar radiation = cooler temps

How is volcanic activity a natural cause of climate change?

• eject material into atmosphere, some particles reflect the sun's rays back to space cooling the Earth but gases can warm the atmosphere

• erupted ash blocks sun

What is the enhanced greenhouse effect?

The impact on the climate from additional heat retained due to increased amounts of CO2 + other greenhouse gases

How are burning fossils fuels a human cause of climate change?

- CO2 is released into the atmosphere when fossil fuels like coal, oil, natural gas and petrol are burnt e.g. in thermal power stations

How is cement production a human cause of climate change?

- cement is made from limestone which contains carbon, when cement is produced lots of CO2 is released in the atmosphere

How is farming a human cause of climate change?

• farming livestock produces a lot of methane

• rice paddies contribute to global warming, because flooded fields emit methane

How is deforestation a human cause of climate change?

• plants remove CO2 from the atmosphere and convert it into organic matter using photosynthesis

• when trees are cut down, they stop taking in CO2

• CO2 is also released into the atmosphere when trees are burnt as fuel or to make way for agriculture

How does climate change affect the environment?

• glaciers melting causes sea levels rising, floods in coastal countries, e.g. Bangladesh

• loss of polar habitats from shrinking sea ice

• changes in precipitation patterns

How does climate change affect people?

• deaths from hotter/colder environments

• water shortages from varied rainfall, can lead to political tensions between river borders

• farmers in high-altitude countries benefiting from warmer weather, higher crop yields, low yields lead to death in lower latitudes

How does planting trees mitigate climate change?

- increases the amount of CO2 that is absorbed from the atmosphere through photosynthesis

How does CCS mitigate climate change?

• designed to reduce emissions from power stations burning fossil fuels

• involves capturing CO2 and transporting it to a safe place where it can be stored e.g. underground

How does alternative energy production mitigate climate change?

• renewables reduce greenhouse gas emissions

• in the UK, more offshore wind farms are being built e.g. in East Anglia, and several wave, tidal and nuclear power projects have been planned

How do international agreements mitigate climate change?

- aims to reduce greenhouse gas emissions and limit global warming, it came into force on 4th November 2016 and has been signed by 195 parties, inc the European Union encouraging developed countries to help developing countries put mitigation strategies in place

How does changing agricultural systems help adapt to climate change?

• planting new crop types that are more suited to the new climate condition in an area e.g. soya, peaches and grapes may be grown in Southern England

• biotechnology is used to create new crop varieties which are more resistant to extreme weather events

How does managing water supply help adapt to climate change?

• water meters can be installed in homes to discourage excessive water use

• rainwater and waste water can be collected and recycled

How are we adapting to rising sea levels?

• predicted to rise 65cm by 2100

• better flood warning systems/defences such as flood barriers e.g. Thames London barrier

• Bangladesh are building raised flood shelters and building houses on embankments

What is mitigation?

developing strategies to reduce greenhouse gas emission

What is adaptation?

changing lifestyle to cope with the consequences of global warming

What is the Quaternary Period?

The most recent geological time period, spanning from about 2.6 million years ago to the present day.