The Science of Climate Change Flashcards
In essence, what is the greenhouse effect?
The trapping of long-wave solar radiation in the atmosphere
Describe the process of the greenhouse effect. Give 4 steps.
- Short-wave infrared radiation comes in from the sun
- Some is reflected back into space by the atmosphere while the rest is absorbed by the Earth
- The Earth warms, and emits long-wave radiation back out (on its way to space)
- Some of that is absorbed and re-emitted by GHGs and clouds
There is a continual exchange of radiation between the Earth and GHGs in the atmosphere. True or false?
True - they are constantly absorbing and re-emitting the radiation to eachother.
Without the Greenhouse Effect, Earth would be too cold to sustain life. True or false?
True
Define weather.
What is happening in the atmosphere in a given moment.
Define climate.
Average weather over longer time frames; includes temperature and precipitation patterns.
Define global warming.
The warming of the planet, based on the average temperature across Earth’s surface.
Define climate change.
Give 5 examples of factors that might change.
The change in climate characteristics over long periods.
Things that might change:
- Temperature
- Rainfall
- Humidity
- Wind
- Frequency of extreme weather events
Name 3 factors that can ‘force’ (affect) Earth’s climate.
- Solar events
- Volcanoes
- The Greenhouse Effect/GHGs
Which GHG has the highest GWP (global warming potential)?
Carbon dioxide
Contributes to approx. 64% of total radiative forcing.
How much CO2 is absorbed by the biosphere and how much stays in the atmosphere?
Approx. 50% each
CO2 has a long half life. How long is it?
Between 300-1000 years.
Which anthropogenic activities produce CO2? Give 3 examples.
- Deforestation
- Oil refineries
- Steel production
Which GHG has the second highest GWP?
Methane.
Contributes to approx. 18% of total radiative forcing.
Regarding methane, how much of it in the atmosphere is from…
a) natural sources
b) anthropogenic sources
a) ~40%
b) ~60%
Methane has a short half life. How long is it?
~12 years.
Which anthropogenic activities produce methane? Give 4 examples.
- Fossil fuel mining
- Cattle farming
- Rice farming
- Landfill decomposition
Which GHG has the third highest GWP?
Nitrous oxide (N20)
Contributes to approx. 6% of total radiative forcing.
Regarding N2O, how much of it in the atmosphere is from…
a) natural sources
b) anthropogenic sources
a) ~60%
b) ~40%
N2O has a medium half life. How long is it?
~114 years
Which anthropogenic activity produces N2O?
Fertiliser production
After CO2, CH4 and N2O, what is the final group of GHGs?
Fluorinated gases
Fluorinated gases have a GWP 23,000x more potent than CO2 - true or false?
True!
If fluorinated gases have a much higher GWP than CO2, why are we not totally fucked?
Because they make up a very small percentage of emissions.
Together they contribute ~12% to total radiative forcing.
Name the three groups that make up fluorinated gases.
- Hydroflurocarbons (HFCs)
- Perflurocarbons (PFCs)
- Sulphur hexafluoride (SF6)
How did we end up with fluorinated gases in our atmosphere?
The Montreal Protocol (ratified 1988) sought to remove-ozone depleting substances from circulation, instead replacing them with these which are a major greenhouse gas lol…nice one boys
Fluorinated gases have a very long half life. How long?
~50,000 years
What does a positive feedback loop do?
Increases the effect of a process
What does a negative feedback loop do?
Decreases the effect of a process
What are the two effects of melting glaciers in polar regions?
- A reduction in the cryosphere, which will lead to further warming
- Sea level rise
Increased global temperatures are causing polar regions to melt. This causes a reduction in the cryosphere, which through positive feedback will lead to further warming. How?
Glaciers melt = reduced cryosphere
Reduced cryosphere = reduced albedo
Reduced albedo = more radiation absorbed by exposed Earth/ocean (not reflected back into space)
More radiation absorbed by exposed Earth/ocean = warmer Earth/ocean
Even if we stopped producing GHGs tomorrow, the oceans would continue to warm. Why?
The timescale that connects surface water to the deep ocean is thousands of years, meaning heat is not yet equally distributed throughout the oceans.
Sea levels rise by two methods. What are they?
- Thermal expansion: increased temperatures cause water to expand and occupy more space
- Increased water in the system i.e. melting of the ice caps
What are the two ways people can die from climate change?
- Directly: killed in an extreme weather event
- Indirectly: killed by a vector borne disease that has increased in range; socioeconomic disruption e.g. famine from crop failure
Give the
a) direct
b) indirect
causes of death from drought.
a) Heat-related mortality
b) Malnutrition from water/food shortage
Give the
a) direct
b) indirect
causes of death from increased precipitation (storms, flooding).
a) Drowning and fatal injury
b) Malnutrition from crop failure
How might water-borne diseases increase due to climate change?
Give examples of water-borne disease.
Increased flooding likely to alter their distribution and contaminate food and water sources.
Diarrhoea, leptospirosis, cholera
Increased temperatures and precipitation will increase vector borne diseases.
- Why will this happen?
- In what two ways will this happen?
- Because mosquitos breed in water and like warmer temperatures.
2.
a. Create a longer transmission season in countries already affected
b. Alter the geographic range to affect new regions
Why would vector-borne disease spreading to new, previously unaffected regions be particularly damaging? Give two points.
The populations lack:
- Natural immunity
- The necessary public health infrastructure to deal with the resultant disease epidemic
Which two vector-borne diseases are of most concern?
Malaria and Dengue
