Global Climate Change Flashcards
What is the greenhouse effect?
The warming of the atmosphere due to insulation by GHGs
How is the greenhouse effect useful?
Maintains a suitable temperature range on Earth by reducing temperature extremes
What is the enhanced greenhouse effect?
The impact on the climate from the additional heat retained due to increased human GHG emissions
What are the 5 main GHGs?
- Carbon dioxide (CO2)
- Methane (CH4)
- Oxides of nitrogen (NOx)
- Tropospheric ozone (O3)
- CFCs
What are the human sources of CO2?
- Deforestation
- Fossil fuel combustion
What are the human sources of CH4?
- Cattle farming
- Rice production
- Landfill sites
- Fracking
What are the human sources of NOx?
- Combustion engines in vehicles
- Artificial fertilisers
What are the human sources of CFCs?
- Air conditioning
- Refrigeration
- Propellants
How is tropospheric O3 formed?
Photochemical breakdown of NOx and subsequent reactions with O2
Which of the GHGs does not occur naturally?
CFCs
What does CFCs stand for?
Chloroflourocarbons
How might climate change affect oceans?
- Change in thermohaline circulation in the N. Atlantic
- Change in El Nino / La Nina
- Sea level rise
Why are sea levels likely to rise?
- Melting land ice increases the volume of water in the oceans
- Thermal expansion of seawater increases volume
Which 2 main factors affect ocean currents?
- Temperature
- Salinity
What effect does increased precipitation have on water salinity and density?
Both decrease as more freshwater is provided
What happens to cold, salty water?
Sinks as density increases
What happens to warm, less salty water?
Rises as density decreases
What is thermohaline circulation?
Circulation driven by temperature and salinity
What is the North Atlantic Conveyor / Gulf Stream?
A 10,000km long thermohaline circulation system which flows NE across the Atlantic
What happens in the Gulf Stream?
- Arctic winds cool water which causes it to sink and move towards the equator
- Warm, less dense water flows across the Atlantic to replace it
Why is the Gulf Stream important for the UK climate?
It maintains temperatures 5-10°C higher than other areas at the same latitude
What effect might climate change have on the Gulf Stream?
- Increased ice melting in Greenland would reduce the salinity of the ocean, therefore decreasing density and making it less likely to sink
- This would reduce the rate of flow of warm water to NW Europe and cause a decrease in temperature
What does ENSO stand for?
El Nino Southern Oscillation
What happens in the Pacific during a regular year?
- Prevailing easterlies (E to W)
- Warm surface water is moved west
- Upwelling of cold water
- Settled weather
What happens in the Pacific during El Nino?
- Prevailing winds may reverse
- Warm surface water is moved east
- Little or no upwelling
- Unsettled weather (e.g. droughts in the west)
How often does El Nino occur?
Every 2-7 years
What happens in the Pacific during La Nina?
- Strengthened easterlies (E to W)
- More warm water is moved west
- More upwelling in E Pacific
- Increased temperature difference
What is the cryosphere?
The components of Earth that are frozen (e.g. ice sheets, permafrost)
What effect might climate change have on the amount and duration of snow and sea ice cover?
Decreased amount and duration reduced albedo and therefore increases insolation absorption
What effect might climate change have on glaciers?
Increased subglacial meltwater provides lubrication for basal sliding, therefore increasing the speed at which glaciers move towards the ocean and increase sea level
What effect might climate change have on ice shelves?
Sea level rise will lead to a loss of ice shelves, therefore causing more rapid glacial advances towards the ocean
What effect might climate change have on precipitation?
Increased temperatures lead to more evaporation and therefore more rainfall
What effect might climate change have on wind patterns?
Jet streams that contribute to rainfall will become slower and begin to meander
What are the ecological impacts of climate change?
- Changes in species range of tolerance
- Population fragmentation
- Changes in migration patterns
What is a species’ range of tolerance?
The range of environmental conditions in which a species can survive
Why is it difficult to predict future global climate change?
- Difficult to differentiate between natural and anthropogenic causes of change
- Timelapse between cause and effect
- Earth’s systems and cycles are not fully understood
What are some examples of natural causes of climate change?
- Milankovitch cycles
- Sunspots
- Volcanic ash clouds
What device can be used to monitor ocean currents?
Argo floats (measures salinity)
How can computer models help predict climate change?
Data is inputted to predict possible future outcomes, and past data can be inputted for events for which the outcome is known to test reliability
What is a positive feedback mechanism?
A chain of events/processes which amplifies the effect of the original change
What is a negative feedback mechanism?
A chain of events/processes which nullifies the effect of the original change
What are some examples of positive feedback?
- Increased melting of permafrost accelerates the release of CO2 and CH4
- Increased temperatures cause ice to melt and reduce surface albedo
What are some examples of negative feedback?
- Increased low-level cloud cover increases albedo
- Increased photosynthesis increases CO2 absorption
What is a tipping point?
A critical threshold that, when crossed, will lead to irreversible changes in the climate system
What is adaptation?
Reducing the impacts of climate change
What is mitigation?
Aiming to solve the causes of climate change
How can agriculture adapt to climate change?
- Growing drought resistant crops
- Urban farming
- Manage water resources efficiently
How can building design adapt to climate change?
- Water efficient fittings
- Reflective surfaces to increase albedo
- Use of insulation (e.g. glazing)
How can flood control adapt to climate change?
- Use of permeable materials for roads
- Flood diversion channels
- Floating houses / use of stilts
How can coastal erosion control adapt to climate change?
- Protection of mangroves
- Protection of sand dunes
- Hard and soft engineering strategies
What is CCS?
Carbon Capture and Storage - technology that can remove CO2 produced by industrial processes
How can carbon sequestration be increased?
Afforestation
What are the 2 main international climate change agreements?
- The Kyoto Protocol (1997)
- The Paris Agreement (2015)
How did the Kyoto Protocol aim to limit climate change?
- Placed emissions limits on countries
- Provided an adaptation fund for LEDCs
- Superseded by the Paris Agreement
How does the Paris Agreement aim to limit climate change?
- Aims to limit global warming to below 2°C above pre-industrial levels
- 5 year cycles of climate change targets
- Part of UNFCCC