2.4 Climate change And Sea Level Change Flashcards
Why does earth’s climate change?
Greenhouse gases
Ice sheet growth - albedo effect
Changes in orbit
Carbon cycle
Explain how the enhanced greenhouse effect causes climate change?
Burning fossil fuels creates CO2 trapping solar radiation adding to greenhouse effect - this is enhanced greenhouse effect
How do volcanoes cause climate change?
Volcanoes emit huge volumes of CO2 into atmosphere
Every 100 million years very large eruptions called Flood Basalts alter climate and cause mass extinctions
What removes CO2 from atmosphere?
Plants and trees by photosynthesis
What is the albedo effect?
How much radiation is absorbed or reflected by the earth’s surface
What reflects most of the radiation?
Ice reflects the most
Land reflects the least
Sea is in between
Why does land most likely make ice sheets at the poles?
Land has fresh water
This freezes easier than salt water
More radiation reflected and earth cools more
Explain the carbon cycle?
- Rainwater dissolves CO2 from atmosphere to create weak acids
- Chemical weathering of silicate rocks by weak carbonic acids
- Weathering produces ions which are washed into the sea by rivers
- Plankton in ocean use ions to create their shells
- Plankton die and carbon shells accumulate on sea bed
- Ocean sediments subducted at ocean trenches and incorporated into magma
- CO2 emitted back into atmosphere by eruptions
Explain the change in earth’s orbit - milankovic cycles?
- Over 100,000 years there is a cycle of change in earth’s elliptical orbit
- Over 43,000 years there is a cycle of change in the earth’s tilt at its axis
- Every 21,000 years there is a cycle of wobble at earth’s axis as it spins
How have humans impacted on climate change?
Humans are the main source of CO2 in the atmosphere
Burning fossil fuels - need to stop and use renewable energy eg solar, wind, tidal, wave, geothermal, hydroelectric, biomass
Nuclear energy doesn’t produce CO2 but releases radioactive waste that needs to be stored for 100,000s of yrs
Renewable energy still expense and insufficient to meet demand so still need fossil fuel present
Volcanic eruptions we can’t stop them from producing CO2
What is carbon capture and sequestration?
The process of preventing CO2 from Power stations + industries from reaching atmosphere
Storing it elsewhere
What are 3 main methods of carbon capture?
- Oxyfuel - nitrogen and oxygen separated, fuel burnt in pure oxygen. Cleaner and CO2 captured
- Post combustion - gases produced from combustion treated and CO2 removed for storage
- Pre - combustion - fuel treated so pure CO2 is produced and stored
What is geological sequestration?
CO2 is captured
Turned into liquid by high pressure
Liquid CO2 pumped into porous and permeable deep rocks with impermeable cap rock
These are often used up as gas and oil reservoirs
What is terrestrial geological sequestration?
Planting trees near CO2 production to absorb it
What are ice house conditions?
The earth is cold enough to support ice sheets all year round
