Climate Emergency Flashcards
The climate system can be though of as a [] that drives heat between the equator and the poles
Heat engine
This engine powers [] and [] circulation, giving rise to our climate
Wind and ocean circulation
Albedo is a measure of . . .
The reflection of solar radiation, relative to the total radiation received
On the albedo scale, what is 0-1 ?
1- reflects all radiation
Snow
Ice
Greenery
Soil
Water
0- black body
[]% of the earth’s atmosphere is []km from its surface
90%
12km
All bodies lose heat to their surroundings through []
Radiation
What aspect of radiation varies with the bodies temperature?
Colour
The sun at []K loses most of its energy in the [] spectrum
5778K
Visible spectrum
Normal bodies emit what type of radiation?
Infra-red
Glass is transparent to which radiation type, but opaque to which other type?
Transparent to visible glass
Opaque to infra red
The earth’s atmosphere has [] which are transparent to [] but opaque to []
Trace gases
Sunlight
Infra-red
Trace gases which are opaque to infra-red radiation from bodies close to Earths surface temperatures are called
Green house gases
Explain the greenhouse gas effect on a greenhouse
Interior warms from short wavelength solar radiation
Glass absorbs longer wavelength radiation
Incoming energy is trapped
Interior temp rises until rate of heat loss = incident radiation
Elevation of surface temp due to atmospheric optical properties is the [], it is why the Earth is []°C but the moon is []°C
Greenhouse gas effect
12
-28
What is the most potent GHG?
Water vapour
What is the water vapour cycle
Higher vapour conc. in air
Traps more heat
Higher temp causes evaporation of sea water
More evaporation, more vapour in the air
What are the other GHGs?
CO2
CH4
CFC & N2O
What is climate forcing?
It is the extra solar radiation needed to obtain the same temperature elevation of the atm. Without the GH effect
(Climate temp + rise due to GHE )
is equal to
Climate temp + forcing
Climate forcing is a function of [] conc. in the atm.
CO2
What is the forcing equation?
ΔF= 5.35ln( C/Co)
Where C is the conc. of CO2 in the atm.
And Co is pre-industrial conc.
Why does the forcing equation follow a logarithmic variation?
CO2 absorption is nearly saturated.
By comparison, increase with forcing for other GHGs is much sharper
What is climate sensitivity?
The global temp rise resulting from forcing equivalent to doubling CO2 conc. over pre-industrial levels
CH4 has a lifetime of
12 years eve for it is oxidised by CO2
What are CFCs?
Chlorofluorocarbons
What are the three stable climate states that could arise in geological timescales?
Snowball earth
Grounded/floating ice and sea level
Runaway greenhouse effect (yeehaw)
What happens in the snowball earth climate state
Proves that the earths surface was entirely frozen at least once
Associated with a low GHG conc.
Ice-albedo feedback causes the ice cover of the earth
What happens in the grounded/floating ice and sea level state
If arctic melted, Earth’s albedo would change but not sea level
This is because floating ice displaces the same volume as melted ice
Sea level depends on fresh water locked in ground ice (glaciers)
What happens in the runaway greenhouse effect ?
This is a state where the feedback between surface temp and atmospheric opacity increases.
Until GHE is so strong that the ocean boils away.
This is thought to have happened on Venus
The use of fossil fuels has increased atm. CO2 from [] to [] ppm
278 - 415 ppm
THATS ALMOST DOUBLE
CO2 in the atmosphere will stay a problem even if emission stopped, true of false?
True
Even if the world were to stabilise emission . . .
CO2 would continue to accumulate, so we must also work on removing CO2 from the atmosphere
What causes sea levels to rise?
Ice sheet melt
Sea water expansion (due to warming)
If large ice caps melt, land on Earth has been [], causing a corresponding [] of the Earth
redistributed
deformation
This is because areas of high pressure (ice caps) are redistributed
in what year is there a risk of 0.5m sea level rise?
2050
What are two predicted consequences of rising sea levels?
increased frequency and intensity of storm surges
projected 800M people at risk
What does an amplified hydrological cycle involve?
higher temp
more evaporation
increased precipitation
higher frequency and intensity of extreme events
(storms, flooding, hurricanes)
What is the main contributor to 1C rise of global average temperature?
rising levels of greenhouse gases
CO2 makes up for what proportion of GHGs in the atmosphere?
2/3
CH4 has caused what proportion of warming?
1/4
CH4 is [] times more potent than CO2 over its [] year lifespan
80 times
20 year
Engineers must . . .
reduce FF emissions, whilst making the transition to lower carbon fuels easier
Reduce cost of lower carbon tech
It is not enough for Engineering solutions to just tackle today’s problems, the must meet future needs and have built in []
resilience
following a []C increase in average global temp . . . What happens to the weather cycle’s viability for influencing design?
2°C
the 20-50 year weather cycle will no longer be a suitable basis for design
Argiculture, fossil fuels and deforestation cause
GHG emissions
GHG emissions cause
Global warming, climate change
GW, climate change cause the following environmental effects
habitat destruction, ocean acidification
Intensified weather events
glacial retreat
coral bleaching
Pest propagation
Habitat destruction leads to
biodiversity loss
ecosystem collapse
GW, climate change cause the positive feedback effects of
snow cover reduction, lower global albedo
water vapour increase
permafrost melt, methane release
glacial retreat leads to
sea level rise
pest propagation leads to
disease
sea level rise leads to
flooded land, crop failure
flooded land and crop failure give rise to
human migration and conflict
intensified weather events lead to
direct human harm
What is the estimated CO2 content in GigaTonnes for the atmosphere
600
What is the estimated CO2 content in GigaTonnes for vegetation
700
What is the estimated CO2 content in GigaTonnes for soils
3000
What is the estimated CO2 content in GigaTonnes for accessible fossil fuels
1600
What is the estimated CO2 content in GigaTonnes for the Ocean
40,000
how many gigatonnes of carbon per year does fossil fuels put into the atmosphere?
8.4
how many gigatonnes of carbon per year does the atmosphere put into the ocean?
2
What is the forcing contribution of CO2 in Wm^-2 ?
1.9
What is the forcing contribution of CH4 in Wm^-2 ?
0.5
What is the forcing contribution of CFC in Wm^-2 ?
0.9