Climate Change
- Created by: 17i.shivji
- Created on: 08-02-20 18:07
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- Climate change
- Evidence
- An increase in average surface air temperature by 1 degree over the last 100 years
- The warmest ocean temperatures since 1850
- A 19cm rise in sea levels since 1900
- Oxygen, carbon dioxide and methane in ice cores and ocean sediments
- Amount of tree rings - how old.
- Thickness of tree rings - How wet and humid the climate was. The thicker the ring, the wetter the climate
- Causes
- Volcanic activity
- Volcanic activity can reduce global temperatures because of the dust and ash that goes into the atmosphere and sulphur dioxide that creates aerosols.
- These volcanic materials reflect incoming radiation back out to space cooling the Earth.
- The Mount Pinatubo eruption of 1991 resulted in cooling of 0.4?C.
- Deforestation
- Forests absorb and store carbon in their trees and soil.
- But if forests are cleared or disturbed, this carbon is released as carbon dioxide and other greenhouse gases.
- Up to a fifth of global greenhouse gas emissions come from deforestation and forest degradation.
- Agriculture
- Producing food globally uses a lot of fossil fuels in the production of fertiliser and pesticides, and in the transportation of food.
- Changing forest cover and marshes to farmland also releases greenhouses gases and removes a greenhouse gas store.
- Keeping animals in large quantities for meat production or dairy products produces a lot of Methane (CH4), a potent greenhouse gas. ntitled
- Cows produce 320g per day which is 37% of the total methane production.
- Rice paddies are also known to produce lots of greenhouse gases
- Fossil fuels
- We use fossil fuels (including coal, oil and gas) in power stations across the world to generate energy.
- Coal is the remains of ancient plants and trees that grew over 200 millions of years ago. Oil and gas is made up of the remains of microscopic plankton.
- Over millions of years these remains become the carbon-rich coal, oil and gas we can use as fuel.
- When fossil fuels are burned they release carbon dioxide into the atmosphere which contributes to global warming.
- Using fossil fuels to generate energy also releases pollutants into the atmosphere - such as sulphur dioxide.
- Orbital changes
- 95,000 year stretch
- The Earth’s orbit slowly changes from elliptical to circular and back again over a 95,000 year period.
- Circular orbits favour glacials, elliptical orbits favour interglacials as the Earth passes closer to the sun allowing for more melting
- 42,000 year tilt
- The tilt of the earth varies slowly over 42,000 year cycles.
- The Earth is currently tilted at an angle of 23.5° to the sun but it can reduce to 21° causes glacials as there is less summer melting at the poles and increase to 24.5° causes interglacials as there is MORE summer melting.
- 21,000 year wobble
- The Earth wobbles on its axis every 21,000 years meaning that the seasons change for the 2 hemispheres.
- At present our orbit puts N-Hemisphere closest to the sun in winter and furthest in summer – ideal for glaciers to develop
- It was the reverse 12,000 years ago and caused the current interglacial
- 95,000 year stretch
- Solar output
- There can be fluctuations in the amount of radiation from the Sun
- If there is a high amount emitted, there will be an increase in Earth’s temperatures
- The Sun’s output energy changes in short cycles (11 years) or longer cycles (several 100 years)
- Periods when solar output is reduced may cause the Earth’s climate to become cooler in some areas
- Most scientists think that changes in solar output don’t have a major effect on global climate change
- Cement production
- Cement is the basic ingredient of concrete, the most widely used construction material in the world.
- Around 8% of global CO2 emissions come from cement production
- Typically, over half of cement CO2 emissions come from making clinker,.
- Since this CO2, is released through a chemical reaction,it cannot be eliminated by changing fuel or increasing energy efficiency
- Volcanic activity
- Effects
- Social
- Increased risk of diseases such as skin cancers and heat stroke as temperatures increase.
- Winter-related deaths decrease with milder winters
- Crop yields affected: maize will decrease by up to 12% in South America, yet will increase in northern Europe
- Less ice in Artic Ocean increase sipping and extraction of gas and oil reserves
- Drought reduces food and water supplies in sub-Saharan Africa.
- Water scarcity in the south and southeast of the UK
- Flood risk increase repair and insurance costs
- 70% of Asia at increased risk of flooding, causing migration and overcrowding in low-risk areas
- Declining fishing in the Lower Mekong delta would affect 40 million, due to changing water quality because of reduced water flow and sea-level rise
- Extreme weather increases investment in prediction and protection
- Skiing industry may decline in Alps as less snow
- Environmental
- Increased drought in areas such as Mediterranean region
- Lower rainfall causes food shortages for oranguatans in Borneo and Indonesia
- Sea-level rise increases flooding and coastal erosion, so défense are under increasing stain
- Ice melts, so wildlife declines, such as Adele penguins on the Antarctic Penisula and polar bears and seals in the Artic
- Warmer rivers affect marine wildlife; for example, the food supply will decrease for the Ganges river dolphin
- Increase in forest growth in Northern Europe
- Forests in North America may experience more pests, disease and forest fires
- Coral bleaching and decline in biodiversity such as at the Great Barrier Reef
- Social
- Managing
- Alternative energy production
- Examples - wind, solar, geothermal, wave, tidal and biomass
- Reduces greenhouse gases compared to burning fossil fuels (coal, oil and gas)
- They will last longer
- They are becoming cheaper and more competitive
- They are expensive and cannot be relied upon to generate electricity
- For example, if there is no wind, sun or waves
- They are expensive and cannot be relied upon to generate electricity
- Carbon capture
- Carbon capture takes CO2 from emission sources and safely stores it underground
- An impermeable ‘cap rock’ prevents it escaping
- It capture up to 90% of CO2 and provide 10-50% of the world’s total carbon mitigation until 2100
- It is expensive
- It is unclear if CO2 would remain capture long term
- It doesn’t promote renewable energy
- Planting trees
- Helps to remove CO2 from the atmosphere through photosynthesis
- It could increase forest carbon storage by 28%
- Oxygen is produced during photosynthesis, and trees provide habitats
- Land may be limited
- Biodiversity is reduced if only one tree species is planted
- International agreements
- Encourage countries to take responsibility for reducing CO2 emissions
- Targets are more likely to be met if legally binding (Paris 2015 agreement)
- Financial support may be provided for LICs
- Some countries are considered to be more responsible
- It is hard to agree targets that go far enough
- They may not be achieved
- It is hard to agree targets that go far enough
- Changes in agricultural systems
- Required to deal with changing rainfall and temperature patterns, weather becoming more extreme and the changing distribution of pests and diseases
- Production may need to move location to suit climates
- Irrigation may be necessary and changes to crops and varieties may be required
- Adaptations are most difficult for poorer farmers, who are most likely to be affected
- Managing water supplies
- Ensures populations can face the challenge of changing rainfall patters
- In London, this involves reducing demand (such as installing water-efficient devices) and increase supply (such as opening a desalination plant)
- Water supplies being under strain, security may be threatened in area areas of deficit
- Especially where there is less political stability
- Reducing risk from rising sea levels
- Could involve constructing defends (such as the Thames Barrier or restoring mangrove forests)
- Raising properties on stilts or relocating people at risk
- There a social, economic and environmentalimplications of these strategies
- Could involve constructing defends (such as the Thames Barrier or restoring mangrove forests)
- Alternative energy production
- Greenhouse effect
- 1. The sun send its energy to Earth as insolation
- 2. Some of this energy is reflected directly back out to space from dust and clouds
- 3. The light energy is converted to heart energy in the atmosphere and at the Earth’s surface
- 4. This rises through the Earth’s atmosphere
- 5. The heat energy is trapped by CO2, methane and water vapour
- 6. Some heat energy escapes to space
- 7. Extra human activity adds extra gases causing extra anthropogenic warming - enhanced greenhouse effect
- Evidence
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