Climate Change Flashcards
Definition of global warming
A progressive increase in global temperatures, either through natural reasons or human activity such as industrialisation, caused by greenhouse gas emissions.
How greenhouse gases contribute to global warming
Greenhouse gases allow short-wave radiation from the sun to pass through to heat the Earth’s surface and lower atmosphere.
The heated surfaces radiate out-going long-wave radiation which is absorbed and re-emitted by the GHGs back to the Earth’s surface.
Increased concentration of GHGs leads to increased trapping of heat causing more warming.
Why global greenhouse emissions are increasing
Increased burning of fossil fuels for electricity/heat/transportation which leads to increase in GHGs resulting in increase in temperature. Industrial processes which release CO2 as well as burning of land and vegetation to clear land for agriculture
Why global warming causes sea levels to rise
1) Global warming will lead to thermal expansion of water
2) Melting ice caps and glaciers will cause water to enter sea from land
3) Sea ice melting, less heat is reflected so more heat is absorbed by Earth’s surface, further contributing to increase in temperatures by positive feedback.
Impacts of sea level rise
1) Flooding
2) Increased soil salinity, reduction of freshwater sources due to saltwater intrusion
3) Increased coastal erosion due to increased wave action
4) Colonisation of habitats by displaced animal populations
Types of greenhouse gases and their origins
Peat bogs, marshes, swamps - methane, nitrous oxide
Car exhaust- CO2
How is CO2 added to the atmosphere through natural and human processes
Natural processes
Respiration by animals and plants releases carbon dioxide to atmosphere
CO2 is released from solution from bodies of water
Natural bushfires where the burning of organic material releases CO2
Natural methane sources from animal/termite/bacterial decay can be oxidised to CO2
Magma contains dissolved gases such as CO2 that can be released during volcanic activity
Human processes
Burning land and vegetation to clear land for agriculture
Industrial processes, such as in cement works, release CO2
Burning of fossil fuels
Increase in decomposing materials in landfills/sewage
Global warming changes in climate and how this affects wildlife
Global warming can cause changes in climate such as storm and flooding in some areas and hotter/drier climate in others / more extreme weather with greater rainfall and severe droughts
Global warming can result in change in length of seasonal periods such as prolonged or shorter winter or summer. Since many species take their cues about when to migrate, flower, nest or mate from seasonal changes in temperature, precipitation and daylight, this may lead to mismatches in the timing of migration, breeding and food availability thus affecting survival of species.
Global warming causes loss in habitat
Global warming can cause loss in habitat, such as more forest fires destroying forested areas, which reduces habitat and foraging areas for native birds in California/Australia. Raised temperatures cause ice sheets to melt in the arctic region, leading to reduction of and more competition for breeding sites for penguins, and reduction of and more competition for prey (seals) as food for polar bears.
Global warming can result in both animal and plant populations to gradually shift upward to higher elevations nd toward northern latitudes where temperatures are cooler in order to stay within their ideal range of environmental conditions
Boreal forests shifting into the tundra, displaced by temperate forests and grasslands
Birds common in Florida like cardinal, mockingbird have moved farther north and are now commonly found in New England and Canada
New species colonising an area may affect ecosystem already there
No suitable habitat for organisms / organisms not able to adapt to new environment → extinction
Interdependence problems where some organisms have a symbiotic relationship and if one species cannot survive in new environment will affect the survival of another species
Global warming results in changes in the sea and water bodes
Global warming can result in the increase in temperature of sea water, resulting in bleaching of corals where corals expel zooxanthellae resulting in eventual coral death, resulting in change in distribution of corals surviving in areas of oceans which are cooler. Marine fish species may shift north towards cooler waters so they can live within their temperature range.
Global warming can result in the thermal expansion of water and melting of land ice causing sea level to rise. Intrusion of sea water into coastal regions increases soil and freshwater salinity which results in lack of suitable habitat for plants and freshwater fish, resulting in their reduced survival and possible extinction.
Global warming and viruses, disease transmission
Global warming is an increase in atmospheric temperatures around the world. Increased temperatures decreases survival of virus and hence lowers human exposure to virus.
Seasonal pattern: with global warming, there are more extreme weather events with summer being hotter and winter being colder. Survival of viruses decreases in hotter summer months due to higher temperature and colder winters results in higher incidence of viral diseases like influenza in winter months.
Geographic pattern: Temperature decreases with increased latitude. Higher incidence of viral diseases around equator.
Global warming and dengue virus
Dengue fever: Mosquito vector, Aedes aegypti, lives and breeds in moist tropical regions. With global warming, the life cycle of mosquito is shorter since increase in temperature increases their metabolic processes by increasing rates of enzyme-catalysed reactions, resulting in faster development rate and decreasing the length of reproductive cycles and stimulating hatching of eggs. More mosquitoes lead to greater transmission of dengue fever. Increased temperatures also results in shorter extrinsic incubation period as virus can reproduce faster in mosquito vector.
Hotter summer months result in increased incidence of dengue fever in summer. Global warming results in temperate regions becoming warmer, such that conditions are more suited for survival of Aedes mosquitoes. Mosquitoes will move to higher latitudes, expanding their distribution. Higher altitudes also become warmer and mosquitoes can colonise altitudes higher up the mountain.
