Climate Change Flashcards
What is the quaternary period?
The quaternary period is the period from 2.6 million years ago to today. It involves the holocene epoch, from 12000 years ago to today, and the Pleistocene epoch, from 2.6 million years ago to 12000 years ago.
What are some ways to measure climate change?
Analysis of pollen and trees - more pollen suggests a warmer climate (indirect data)
Weather recordings - direct data measuring the temperature at different locations and times
Ice cores and ocean sediment - atmospheric gases are trapped in rings in ice cores. Oxygen in sediment layers can be used to calculate temperature (indirect data)
Landforms: rocks and fossils - covers longer time periods
What recent evidence is there for climate change?
Shrinking glaciers and melting ice - glaciers are shrinking and retreating, while sea ice has thinned in some places to an all time low
Rising sea level - freshwater ice has melted and thermal expansion means ocean water has expanded, so sea levels are higher
Seasonal changes - seasonal activities like tree flowering and bird migration are advancing in date
What are natural causes of climate change?
Volcanic activity - ash and sulphur dioxide produced by eruptions spread around the atmosphere and can block out and reflect sunlight back into space, cooling the Earth for a few years. Solar activity/ output - sunspots are dark patches on the Sun caused by magnetic activity. The Sun has to fire out more solar energy around it to make up for it, warming the Earth. The number of sunspots vary from minimum to maximum and back over 11 years. Orbital changes (Milankovitch cycle) - eccentricity cycle: over 100000 years the Earth's orbit varies from circular (cooler) to elliptical (warmer and back again. Axial tilt: over 41000 years the axial tilt varies from 21.5 degrees (warmer) to 24.5 degrees (cooler). Precession: over 26000 years the Earth's axis wobbles a complete cycle.
How does the greenhouse effect work?
The Sun sends short wave radiation to the Earth. Only some of the energy reaches the Earth’s surface - the rest is either reflected or scattered by gases in the atmosphere. Natural greenhouse gases e.g. CO2 and methane allow heat to pass through. The heat reaching the surface us either absorbed or reflected off the Earth’s surface.
The reflected heat is long wave radiation. Greenhouse gases trap some of this heat which is absorbed by the atmosphere, while some escapes into space. Without this the Earth would be too cold for life.
What is the difference between the natural and enhanced greenhouse effect?
The natural greenhouse effect comes from naturally formed gases in the atmosphere. The enhanced greenhouse effect comes from gases released by human activity like burning fossil fuels, which increases the effect of the greenhouse effect.
What causes different greenhouse gases to be released? What % of the enhanced greenhouse effect do they each account for?
CO2: vehicle and factory emissions, burning fossil fuels, deforestation. 60%
Methane: rice production, cattle farming, mining for fossil fuels, melting permafrost, wetland marshes and swamps, decaying vegetables in landfill sites. 20%
Nitrous oxide: car exhausts, sewage treatment, agricultural fertilisers, power stations producing electricity. 15%
What are social impacts of climate change?
More heat waves can result in heat related deaths and skin cancer
Malaria might spread further
Fishing will decline in placed due to reduced water flow
More water shortages
What are environmental impacts of climate change?
Coral reefs could see a loss of biodiversity and coral bleaching from more acidic oceans
Amazonian rainforests may become savannahs, causing extinctions
Wildlife in polar regions will decline as ice retreats
70% of Asia may be at risk of increased flooding
Mediterranean regions may see increased drought
What are economic impacts of climate change?
Crop yields will decrease in some crops but increase in others
Fishing will decline in East Asia from higher temperatures and more acidic seas
Skiing resorts may have shorter opening seasons from less snow
What is mitigation?
Strategies that can be local or global and deal with the cause of the problem e.g. reducing greenhouse emissions
What is adaption?
Strategies that respond to the impacts of climate change and try to make populations less vulnerable e.g. moving away from coastal areas. They are usually local
What is alternative energy production?
Finding new ways to produce energy without producing CO2. It means we can still produce energy without harming the atmosphere, but some strategies still produce greenhouse gases e.g. biomass, it looks bad, and depends on geography. In Iceland 90% of energy is geothermal from volcanic activity.
What is carbon capture and storage?
Capturing CO2 from power plants, then pumping it through pipelines to a place where underground rock formations can store it safely and permanently. There is plenty of space to store it (space for 1-4tr tons of CO2 in the USA), but it distracts governments from switching to renewable energy, it is very expensive, and there is a chance of leakage. By 2050, CCS could provide more than 20% of the UK’s electricity and save us £30bn in meeting climate change targets.
What is planting trees?
Planting trees, as each tree takes in 2kg of CO2. It is cheap and easy to do, promotes ecosystems, and looks nice, but takes up lots of space, releases carbon when trees die, and takes time to grow. In a plantation in England 2500 trees are planted per hectare.
