Unit 7 (Kognity Only) Flashcards
Mitigation
A human intervention to reduce sources or enhance the sinks of greenhouse gasses. It involves anthropocentric intervention reducing the forcing of the climate system
Geo-engineering
Carbon dioxide being removed from the atmosphere
Reducing energy use
Reducing consumption and therefore fossil fuels can reduce emissions. eg: hybrid and electric vehicles
Substitute fossil fuels which can provide for transport include:
Biodiesel (made from rapeseed, palm, or sunflower oil), Bioethanol (Made from crops being fermented to produce it, EG: sugar can, maize, or sorghum) - in brazil, bioethanol from sugar cane is used as fuel for vehicles, and car companies have developed 100% ethanol engines
Issues with growing biofuels
Cost of land and reduction of land to supply food which increases food cost, production of them can potentially cause pollution from the use of fertilisers and pesticides and compete for limited water resources. The cultivation of biofuels may require clearance of natural vegetation, destruction of ecosystems and loss of biodiversity
Best management practices to reduce GHG emissions from farming
Use less fertiliser, adding nitrification inhibitors to the fertiliser to reduce production of nitrous oxide, recude methane generation from livestock, collecting and utilising methane emissions from biodegradation of animal waste as a source of energy, cultivating rice varieties
Using fertiliser can reduce….
Nitrous oxide (N2O) emissions. Fertilisers should only be applied when required and when there is maximum uptake. Or when there is low risk of run-off in dryer conditions
Reducing methane generation from livestock by:
Selective breeding to have cattle produce less methane, or changing the feedstock
Cultivating rice varieties can apply when
The rice can be grown in drier conditions with higher yields which will reduce methane emissions
Geo-engineering
manipulating the earth’s environmental systems to counteract impacts of climate change
Geo-engineering methods do not address
The causes of climate change, but could be used to complement GHG emission reduction strategies. Little is known about their effectiveness since most have not been tested
Two key approaches to geo-engineering
Carbon dioxide removal from the atmosphere, solar radiation management
Carbon dioxide removal methods
Carbon capture and storage, ocean absorption, Use of biomass, UN-REDD, land use management
Carbon dioxide removal (CDR)
Methods are unproven and it is likely to be a slow process taking decades to stabilise atmospheric levels
Land use management
Used to protect and enhance plants that absorb CD, reducing atmospheric levels.
Carbon sinks can be protected and enhanced by
Afforestation of land, restoration such as reforestation of degraded land, reduced deforestation, use of farming practices which encourages retention of carbon stores within the soil as organic matter.
No tillage is recommended because
Tillage disturbs the soil, increases erosion and loss of organic matter
UN-REDD
A collaborative programme to reduce emissions from deforestation and forest degradation set up by the UN in 2008. It recognises the economic value of forests as carbon since, and the potential of indigenous people to effectively manage the forest
The UN-REDD supports developing countries to:
Reduce GHG emissions from forests, invest in low carbon energy sources
Use of biomass
When plant organisms die, the biomass degrades releasing carbon dioxide. An alternative is to harvest and use the biomass to generate fuel (replacing fossil fuels) or to bury the material
Carbon capture and storage (CCS)
Removes carbon dioxide from the atmosphere either chemically to form carbonates or by compression and transport to a site of permanent storage. They are likely to be expensive and are under investigation
Carbon capture and storage approach techniques
Aire could be filtered through absorbent material that removes the CD. Storage could be underground sites such as geological foundations that previously contained oil or gas reservoirs
Ocean absorption
CD is absorbed by photosynthetic phytoplankton in the ocean. Then the carbon moves through the food web and when organisms die they sink to the lower layers. Then they enter storage within the sediments. This absorption of carbon dioxide from the atmosphere and its movement into deep ocean is known as the biological pump
The biological pump could be further enhanced by:
Fertilising the oceans with nitrates, phosphates, and iron, to encourage photosynthesis by phytoplankton. Or, increasing upwellings eg: using mechanical pumps to move cold nutrient rich waters from lower lawyers to the surface, encouraging photosynthesis and enhancing CD uptake. Consequences are unknown
Solar radiation management (SRM)
Theoretical and focus on increasing the reflection of sunlight back into space, reducing total solar radiation absorbed by the earth
Examples of increasing reflection from the earth’s surface
Painting rooftops with white reflective paint, growing plants with high reflectivity (Genetically engineered crops/grasses with high albedo), covering areas with reflective material (covering deserts with reflective plastic sheets
Other options for solar radiation management (SRM)
Use solar deflectors in space, enhance the reflectivity of clouds by increasing particles that attract water molecules, use aerosols to increase the albedo effect (however the effect and impact on the stratospheric ozone are unknown for this)
International collaboration
Vital for effective mitigation and adaption globally. However compliance to international agreements relies on good will and self-policing. Regional and national legislation are often more effective with clear monitoring and enforcement
International Panel on Climate Change (IPCC)
Set up by the United Nations environmental programme (UNEP) and World meteorological organisation (WMO) in 1988.
The aim of the IPPC
Provide a scientific view of the current knowledge and understanding of CC and its impacts. It involves sciences and governments from across the world, hence their work has wide ownership to help influence national policies
United Nations framework convention on climate change (UNFCCC)
Signed by 154 Nations during the earth summit in Rio in 1992. It came into force in 1994 with the aim of stabilising atmospheric gas levels, providing a framework for protocol agreements. Parties meet each year to discuss process and set targets.
Kyoto meeting of the UNFCCC
Took place in 1997 and led to the Kyoto protocol which set targets on GHG emissions coming into force in 2005
Kyoto Protocol 2005 targets:
Overall global reduction of about 5% of CD emissions of 1990 levels by 2012. Individual targets for each country by 2012
Pros of Kyoto Protocol
Sets targets to reduce GHG which causes global warming and CC, provides forums to share data and practices, counties can opt to reduce GHG emissions in other countries (where it may be cheaper) and reduce overall levels, established the adaption fund that financially supports vulnerable communities in developing countries with adaption, Nations can use cap/trade, emission trading to buy and sell
Cons of Kyoto Protocol
Goals for 2012 were not met, viewed by some nations as reducing rate of industrial development and economic growth by increasing production cost, developing countries who are large emitters were excluded (China, India), some organisations argue that ar gets were not stringent enough to reduce risk of CC, not all countries ratified any of the protocols and did not need to cut emissions, decisions require consensus
National adaption programs of action (NAPA)
The UNFCCC requires LEDCs to produce a NAPA highlighting areas most vulnerable to CC and where adaption is most required. Selected projects are financially assisted
Political commitment to take action and reduce levels driven by
Public opinion of the environment and understanding of climate change, effect on industrial and economic growth, dependence on income from export of fossil fuels, politicians
Environmental lobby groups
Raise environmental awareness through public awareness campaigns and mobilise the public to influence governmental decisions.
Advocates of fossil fuels
May petition politicians with their perspective to avaoid change
The cost of abatement
Could reduce growth rates
Politicians
Keen to be viewed favourable to win another term in office and usually favour decisions with short term benefits.
Tackling climate issues requires
Action over long term which means that benefits can be difficult to measure
Adoption of mitigation and adaption strategies can be impended by:
Insufficient knowledge of impacts, poor integration into policy and planning at national to local level, poor communication, limited regulation and accountability, inertia and procrastination, insufficient funds and technology, political instability
Poor communication and sharing of information results in
Governmental departments working in isolation from each other on a common project (Eg: essential infrastructure improvements involving energy, water, and transport)
The impacts of climate change are
Not evenly distributed
Some of the most vulnerable countries
Have the least resources which makes adaption difficult (EG: Bangladesh is a low lying coastal area)
Strategies to overcome the barriers to mitigation and adaption
Sharing knowledge, education/public awareness campaigns, efficient communication, consideration of mitigation and adaption as complementary, governments, businesses, and communities to work together and support action, setting achievable and timely goals, sufficient financials, access to technology and expertise
Commitment at all levels
Mitigation and adaption strategies need to be fully embedded into the political and economic decision making processes from national to local levels
The capacity to take on climate change action
Varies from country to country and is limited in developing countries by access to the required funds, technology, and expertise meaning wealthier countries need to help poorer countries with support to deal with climate change
Adaption (IPCC definition)
The process of adjustment to actual or expected climate and its effects
Natural systems (Adaption)
Human intervention may facilitate adjustment to expected climate and its effects
Human systems (Adaption)
Seeks to moderate or avoid harm or exploit beneficial opportunities
Mitigation and adaption contrast
Mitigation addresses the causes of climate change by reducing emissions of GHG, adaption is focused on dealing with their effects
Adaption strategies are necessary to
Minimise negative effects and take advantage of any new favourable conditions
The long residence period of GHGs in the atmosphere mean
That even if GHG emissions were dramatically cut, past emissions will continue to influence climate
Differences between mitigation and adaption
Effects of mitigation can be seen on a global scale with adaption being at a local level. Success of mitigation is easy to mesure whearas success of adaption is more complex
Measuring mitigation
Through reduced levels of atmospheric GHG
Through effective adaptation
We can develop the resilience of our infrastructure and built environment to climate change.
Regulation
Used to implement adaption and to have contingency plans for extreme events. Early warning systems give local people time to prepare (EG: cyclone, evacuate and find shelter)
Adaption mesures are categorised
Based on sectors
Sectors of adaption
Water resources, agriculture and fisheries, Ecosystems, coastal/low lying areas, health, weather, migration
Weather
Seed clouds to encourage rainfall, plant trees to encourage more rainfall
Water resources
Reduce demand with conservation strategies, improve water supplies through the use of desalinisation plants, increase reservoirs, harvest run-off more effectively
Flood risk
Plan water catchment and run-off to minimise flooding, ban building on river flood plains or in areas prone to flooding, modify infrastructure and buildings such as adapting sewage to prevent overflow or building with garages or on stilts, use of flood barriers to drain or diverts water, SUDs (sustainable urban draining) in planning regulations
Agriculture
Using cops that reflect changing conditions, change to crops with high yield, alter time of planting and harvesting to match change in conditions, employ water conservation techniques to maximise use of limited water (micro-irrigation), increase retention of soil moisture reducing erosion via use of terracing and wind breaks, store rainwater, breed drought tolerant crops
Crops that reflect changing conditions
Salt resistant, flood resistant, pest resistant, need less water, grow at higher temperatures
Fisheries
Reduce collapse of fish stocks by reducing intensity, reducing catches, and making fishermen seek employment in other areas
Ecosystems
Adjust to biome shifts by expanding conservation towards the poles, develop forest fire management (wind breaks to prevent spreading), connecting protected areas with corridors allowing movement of species adapting to changes, protect vulnerable zones like coral reeds and mangroves including pollution and over exploitation prevention
It has been predicted the the Carteret Islands off Papua New Guinea
Will be submerged by 2020, making residents relocate to other areas
Health
Improve public health programs, vaccinate against waterborne disease (Typhoid), vaccinate for other diseases such as cholera and polio, be prepared for treatment of likely injuries from climate events, mother and surveillance that raises an alarm at increased risk of health issues
Coastal systems and low lying areas
Improve management of rising sea level and storm surges , ban on developments in LLA, contingency planning for humans, Building and re-enforcing sea wall and coastal defences, move dangerous facilities way from LLA eg: nuclear power stations, managed retreat which may involve compensation and relocation of residents
Sea walls and coastal defences
Groynes and beach replenishment programs which dissipate energy and impact of incoming waves
Water vapour, positive feedback
Higher surface temperature - increased evaporation from oceans and surface waters - more water vapour - enhanced green house effect (if temperatures rise, more water evaporates)
Water is a
Green house gas, meaning it increases temperature
Ice albedo
Ice and snow have a reflective surface meaning they have a high albedo. If temperatures increase, they melt, reducing the amount of solar radiation reflected back into space
Dark surfaces
Replace ice and snow and increase absorption of sunlight and contribute to global warming. Higher temperatures result in more ice and snow melting
Methane
GHG
Permafrost
Increase in temperature results in melting of permafrost which releases methane
Carbon dioxide solubility
If temperatures increase, the solubility of carbon dioxide i the oceans decrease. The release of CD into the atmosphere results in further warming
Plant photosynthesis (Negative feedback)
If temperatures increase the levels of plant photosynthesis rise with more CD absorbed. This reduction in atmospheric levels results in global temperature reduction
Cloud cover leads to
Positive or negative feedback depending on the temperature (altitude) and optical properties (particle size, solid or liquid)
Cloud cover negative feedback
Dominates in low clouds that reflect some of the incoming solar radiation back into space increasing heat loss and causing global cooling
Cloud cover positive feedback
Dominates in high cloud cover that acts as a blanket retaining heat radiated from the earth’s surface, increasing the temperature
Fossil Fuels are formed from
Dead plants and animals under pressure over millions of years. They provide a finite source of energy and if use continues they will eventually become exhausted
Advantages of fossil fuels
High energy content, currently relatively abundant, relatively cheap, infrastructure is set up for its use in most countries (eg: road and rail links and connection to the electricity grid)
Disadvantages of fossil fuels
Finite (not sustainable), extraction destroys habitats and reduces biodiversity in certain areas, combustion of FFs produces GHG, Transport FFs product emissions of CD, NOx, SO2, and particulates, Power plants require large supplies of water which reduces other uses and impacts aquatic ecosystems, discharge of waste water can result in thermal pollution of aquatic ecosystems
Coal is….
A hard solid that contains carbon, hydrogen, nitrogen, and sulphur compounds. It is the most abundant fossil fuel
Coal is obtained from…
Deep mines or open mines
Limitations of mining
Hazardous to human heath (exposure to coal dust leading to bronchitis and “black lung disease”), a dangerous occupation with thousands of deaths each year, contaminates aquatic systems with toxic metals (acid mine drainage), burning of coal produces ask containing metal oxides and alkali requiring disposal
Locations where Coal is found
The largest reserves are in China, USA, Russia, and India. With China, USA, and India being that top producers
Oil locations
Largest reserves are in Saudi, Venezuela, Canada, Iran, and Alaska. The top producers include Saudi, Russia, and the US
Oil refineries seperate oil into different products that include:
Residue containing bitumen used in road building, fuel oil for ships and power stations, diesel for cars and lorries, kerosene used by aircrafts, gasoline for cars, various chemicals and plastics and fertilisers
Oil limitations
Waste from the refinery process includes slurry containing metals and toxic compounds, offshore extraction resulted in the Gulf of Mexico spill, drilling can pollute underground aquifers, transport through tanker ships, pipes, trucks, and rain can result in spills accidentally affecting marine life.
Oil usually…
Is pumped from underground reservoirs
Positive of oil
Produces less emissions of CD, NOx, SO2 and particulates than burning coal but significantly more than natural gas
Natural gas
Comprised of mostly methane but also ethane, butane, propane, and pentane. It has lower nitrogen and sulphur content than oil or coal resulting in less harmful emissions (producing less CD, NOx, and SO2 and particulates than other fossil fuels.)
Largest reserves of natural gas
Russia, Iran, Qatar, and Turkmenistan. Top producers being US, Russia, and Iran
Fracking
Has been expanded to obtain shale gas (in the US this contributes to a third of gas production). Fracking can potentially contaminate groundwater, pollute surface waters with waste products, contribute to seismic activity
Disadvantage of natural gas
Leaks can be difficult to detect because the natural gas is odourless, colourless, and tasteless. Therefore, hydrogen sulphide is often added to aid leak detection
Nuclear power plants are concentrated in
North America, europe and parts of Asia
In France (Nuclear Power)
75% of electricity is generated from Nuclear Power
Uranium is mines in
Kazakhstan, Canada, Australia, Namibia, and the US
Nuclear power generation
The ore is processed and purified prior to forming fuel used in a nuclear reactor. Neutrons start a chain reaction where energy is produced from the splitting of uranium atoms (nuclear fusion) Heat generated turns water into steam which is fed through a pipe to a stream turbine. The streams rotates blades within the turbine generating electricity
Used nuclear fuel
Generates a lot of heat and contains highly radioactive material hence is usually stored in lead containers, immersed in cooling ponds
Dispersal of radioactive materials is caused by
Chemical corrosion of the container, microbial action, geological change (EG: earthquake or volcanic activity), human activity (EG: terrorism), contamination of groundwater
Radioactive waste management
RW is generated at all stages of the nuclear fuel cycle, the time to decay ranges from seconds to years. The main route of disposal by most countries is underground repositories
Low level waste
Filtered and hen disposed of into the environment (EG: through atmospheric emissions or waste water discharge)
Solid waste disposal
such as paper towels and gloves used on site are buried underground, other waste material is stored in lead covered stainless steel containers
Nuclear power is sometimes referred to as….
A ‘clean’ energy source because it provides few emissions that contribute to GHGs, acid rain, or urban pollution
Advocates for nuclear fuel (including technocentric) will argue that tech will
Provide a solution to the radioactive waste created, provide a replacement for Uranium as a fission material that produces less radioactive waste and is more abundant
Advantages nuclear power
Do not produce CD emissions, reducing risk of climate change, causes less deaths compared to fossil fuels (EG: coal mining accidents, premature death related to pollution)
Disadvantages of nuclear power
Generation of nuclear waste with high radioactive levels that will last for thousands of years, risk of nuclear accidents, potential use of radioactive material from power stations for nuclear weapons, high capital cost and decommissioning cost (when power plant is closed and dismantled)
Renewable sources of energy
Hydropower, solar, biomass, geothermal, wave, tidal
Advantages of renewable energy
Improvements to local air quality (less production of primary pollutants such as SO2 and NOx and secondary pollutants such as ozone), reduced GHG emissions (CO2), employment opportunities, improves energy security
Factors to accelerate growth of renewable energy
Decline in fossil fuel reserves forcing prices up, techno developments improving efficiency of renewable energy and capital cost, governmental support through economic incentives (subsidies), increase awareness of environmental impact of using fossil fuels (CC), need to meet international targets (Reduce CD emissions)
Solar power - the factors influencing the amount of solar radiation that reaches the planet surface include:
Tilting of the earth reflecting the season (EG: highest radiation occurs during the summer months), amount of clouds cover
Two types of solar panels include
Solar thermal panels (heat water and buildings), Photovoltaic panels (converts sunlight to electricity)
Solar thermal panels
Fitted onto the roof of buildings. Air can be warmed and then passed back into the building. Water can be heated then either stored until required (hot water) or stored to transmit its heat (eg: internal wall). The heat form water is released during the night to maintain room temperature
Photovoltaic Panels
Efficiency ranges from 10-20%. Cost of production and installation is relatively high, although running costs are low. Manufacture of solar panels produce pollutants such as CD when setting up but no emissions when running, Panels called Heliostat can track the sun’s movement maximising electricity
Advantages of solar power
Silent, can be used in remote areas, low running cost, sunlight is free, once operational does not produce particulates that contribute to urban air pollution, acid rain, or climate change
Disdvantages of solar power
Needs sunlight which varies regionally and is weather dependent, relatively high capital cost, production of panels creates pollution, no electricity is produced at night meaning electricity produces Ned’s storing for when required
Wind power
Wind turbines that produce electricity are called aero-generators, they usually have fewer blade than the traditional windmill, and therefore require stronger winds to get started. Int he northern hemisphere, higher energy demand during winter is matched by a greater number of windy days and higher wind speeds (UK for example)
Ideal conditions for wind power (choosing where to cite them)
Top of hills here they could be considered to be visually intrusive and a blot on the landscape. Opponents also cite noice produced and interception of bird migratory routes.
Advantages wind power
Renewable (inexhaustible), sustainable, large (abundant) supply available, can be used in remote areas, does not pollute, operational cost is low
Disadvantages wind power
Wind dependent which varies from place to place and can be unpredictable, noise pollution, aesthetically displeasing, can kill birds/bats, high capital cost (manufacturing and installation), electricity needs storing until required
Offshore wind power
Although wind farms can be sited offshore where winds are stronger, there are other concerns: visual impact on seascape, corrosion of the aero generation, aerogenerator vibration impact on sea life, disruption to shipping routes, reduced fishing grounds, potential impact on seabirds
Hydropower producers
China, Brazil, and Canada. Paraguay generates most of its electricity from hydropower via the Itaipu and Yacyreta Dam shared with Brazil and Argentina
Hydropower
The most renewable source of energy currently, energy obtained from the movement of water has historically been used to drive a variety of machinery from grinding flour to sawing wood. HEP is produced when flowing water drives turbines connected to a generator which converts mechanical into electrical energy
HEP schemes
Associated with building reservoirs for water resources. The dam wall built to maintain water in the reservoir also raises the height of the water prior to reaching the turbines which increases the amount of power generated from the falling water.
Hydropower advantages
Sustainable energy, low running cost contributes to economic development, dam construction increases water resources and reduces risk of downstream food, does not produce urban air pollutants, the reservoir can provide an ecosystem for fisheries and offer recreational activity (water sports)
Hydropower disadvantages
High capital cost, Dam construction leads to displacement of peoples potential seismic activity, loss of habitat / species biodiversity, situation in the reservoir and loss of sediment downstream, disruption of migratory route for river organisms, decomposition of the biota flooded to create the reservoir can result in emissions of methane and CD
Geothermal energy
Energy from the interior of the earth that sometimes leaks through faults and fractures to the surface of the earth. Groundwater heated by it can reach the earth’s surface as hot springs and geysers. It can heat buildings and generate electricity
Enhanced geothermal systems
Created when holes are drilled into heated areas called ‘hot dry rock’ through which pressurised water is passed and collected as steam used to drive turbines that generate electricity
Advantages geothermal energy
Cheap to operate, low emissions of carbon dioxide and other GHGs, reliable supply in some areas, sustainable energy supply
Disadvantages geothermal energy
High capital cost (drilling can be expensive), poisonous gases from within the earth can be released (methane, hydrogen sulphide, ammonia, CD - but quantities are low compared to FF use), historically limited to areas near volcanic activity (boundary or tectonic plates)
Energy security
“Uninterrupted availability of energy sources at an affordable price’ They are not distributed equally around the world with some regions having large fossil fuel deposits
Fossil Fuel exporters
Saudi, Russia, Canada. Countries which produce surplus electricity such as Paraguay sell electricity from hydropower to Brazil and Argentina. Some countries rely on imports to meet their needs such as when consumption exceeds national production. This makes them vulnerable to political changes in the exporting nation
Energy security depends on
Adequate supply of energy which matches demand, reliable supply not interrupted by conflict, affordable supply to ensure access to all
A reduction in energy supply effects
Everyday activities, transport, industry, national economy
Threats to energy security
Political instability / conflict in an exporting country, accidents or natural disasters, exhaustion of resource, risk of terror attacks on source or supply infrastructure
Risk of threats to energy security can be reduced by
Reducing imports and becoming more self-sufficient in energy supply (diversifying sources of energy to find FF alternative, exploiting indigenous resources, reducing demand by increasing energy conservation measures), reducing reliance on one or two exporting countries and using more countries to spread the risk
Iceland facts
Aim of using renewable resources to become energy independent by 2050, electricity form heat and transport comes from renewables. 20% hydro, 66% geo (most homes heated by geo), investing in wind power, FFs are used for vehicles boats and sometimes industrial. They plan to replace imported FFs with hydrogen fuel cells
Factors affecting energy choices
Availability, sustainability, scientific / technical development, cultural, political, economic, and environmental
Energy availability
Depending on location. Topography (hillsides for wind, rivers for hydro), Geology (some countries have an abundance of fossil fuels or relatively easy access to geothermal power)
Energy sustainability
Many countries are beginning to consider energy choices over long term and investing in renewables that will not run our like non renewable FFs
Scientific and technological developments
Increasing the choices of affordable alternatives (eg: technology has decreased cost of photovoltaic panels), new options in the future
Cultural attitudes
Some communities have a more nature centred EVS and are more proactive in changing behaviour to reduce energy and polluting less
Politics
Some national governments have greater political will than others to improve long term energy security and make dramatic changes to policies that alter energy sources and individual lifestyles. Governments often make decisions that reflect changing values of the population they represent. International agreements may be responded to by governments (eg: emission targets)
Economics
Energy sources need to be economically visible as they must be affordable to all to ensure full access. Economic weather of a country may limit the choice of energy sources
Environmental impact
There is a general drive by countries to reduce GHGs such as CD and move away from coal and oil to less pollutant resources such as wind and solar
In addition to sun emitted and the orientation of the earth, other factors affect our climate including
Atmospheric and ocean circulation systems, concentration of greenhouse gases, volcanic activity, feedback cycles
More radiation reaches
The equator than the polar regions. Therefore, temperature is higher in the equator and lowest at the pole. The energy from the equator is transferred towards the poles through atmospheric and ocean circulation systems
Ocean circulation systems are caused by
Winds and difference in water temperature and salinity
Wind occurs as a result of differences in air pressure
Low pressure occurs when air is warmed - it expands and rises forming clouds. High pressure is related when a reduction in temperature cools the air which contracts becoming denser and descends which results in clearer skies and calmer weather conditions. Movement of air from high to low air creates wind (Replacing rising air)
Volcanic activity
Has a short term effect on climate. Emissions from volcanics include ash and gases such as sulphur dioxide. The latter reacts in the atmosphere forming a sulphate aerosol which reflects solar radiation into space causing global cooling
A rise in the concentration of GHGs in the atmosphere:
increases the amount of energy absorbed raising global temperatures. Evidence is found within direct temperature measurements and deep sea sediments and ice cores shaken from the Antarctic, Greenland, and mountain glaciers
Climate
“Average” weather over the long term - often regionally
Weather
Short term conditions (day to day) at a local level. Changes are often presented as statistics and trends can be used to predict future climate
Factors outside earth affecting climate
Solar radiation emission form the sun, tilting and orbit of the earth
Factors within the earth affecting climate
Atmospheric and ocean circulation systems, volcanic activity, feedback cycles, GHGs that trap heat and warm the land, oceans, and atmosphere
Solar radiation from the sun
Drives the earth’s climate and changes the amount of energy reaching the earth’s surface depending on energy emissions and position of the earth in relation. It has changed in the past with a cycle of 11 years with periods of low and high emission. This variation has a minimum impact on climate with no recent significant changes
When the northern hemisphere tilts 23.5º north towards the sun
It absorbs more sunlight and energy resulting in summer season, The southern hemisphere is tilted away from the sun leading to winter there, with little light reaching the South Pole
When the Southern Hemisphere is tilted 23.5º towards the sun
It is winter in the north making it dark in the North Pole until spring, Summer is resulted from more sunlight and solar energy
The earth’s eccentricity
The orbit of the earth around the sun is not circular, but is elliptical. The variation in the earth’s eccentricity has a cycle of 100,000 years. Elliptical orbit means the distance of the earth from the sun varies through the year, with the closest point currently occurring in January. Nevertheless, there is little change in the amount of energy reaching the earth.
The Milankovitch cycle
The cycles of axial tilt, precession and eccentricity. They all influence the amount of sunlight reaching the earth. It contributes to the earth’s fluctuation between glacial (ice age) and interglacial periods
Tipping point
The threshold at which a sudden and irreversible change occurs
Climate change is expected to result in
Uneven rainfall with increased precipitation in high latitudes and decrease precipitation in mid/dry latitudes
El Niño
The act if the climate in one part of the world can influencing climate in another via atmospheric and ocean circulation systems. El Niño events in the equatorial Pacific Ocean influence weather in North America and Europe.
El Niño events
Occur every 2-7 years and can last from a few months to more than a year
A change in water temperature and surface winds in the Eastern Pacific
Contributes to an increase in surface water temperatures, reduction in nutrients released from deep waters, adversely affecting primary production and fisheries.
El Niño events develop when: (Water)
Warm surface water in the Western Pacific Ocean extends eastwards resulting in warmer temperature in the Eastern Pacific Ocean and lower pressure above South America. Rising moist air results in rainfall and flood risks in the region.
El Niño events develop when: (Air)
Air flows from the WPO (high pressure, descending air) to the EPO (low pressure, rising air). West air mass is now drier East Asia and Australia experience less rainfall / risk of drought
In the absence of El Niño: (Water)
In the WPO, high surface water temperatures cause evaporation resulting in development of low pressure. This leads to heavy rainfall over East Asia and parts of Australia.
In the EPO, upwellings bring cold deep waters to the surface, lowering surface water temperature resulting in high pressure.
In the absence of El Niño: (Air)
Offshore winds from South America, (land to sea) contribute to dry weather conditions. The difference in atmospheric pressure between the West/East Pacific ocean results in air moving from East (high pressure, descending warm air) to West (low pressure, rising air)
