Greenhouse Effect and Radiative Forcing Flashcards
What is radiative forcing?
Is used to quantify the strength of perturbation (or energy imbalance) to the climate system in units of power.
What is net total radiation?
The sum of upward and downward solar shortwave and terrestrial longwave radiation.
When is radiative forcing positive?
When the change in net radiation is downward (more warming of the atmosphere and surface)
What is ‘climate sensitivity’?
how much surface warming takes place with a doubling of CO2 concentration in the atmosphere.
Which gases emit and absorb longwave radiation?
greenhouse gases
Why is Venus so hot?
Because of it’s enormous greenhouse effect. It is nearly 100% CO2 in its atmosphere.
What contributes to the Natural greenhouse effect?
Water vapour
Clouds
other gases (mostly CO2)
Why are there annual oscillations in CO2?
Global photosynthesis then respiration
How fast is atmospheric CO2 increasing over the last decade?
2ppm per year
What are the main anthropogenic sources of methane?
rice paddies, cattle, biomass burning, fossil fuel production, landfills.
What are the main natural sources of methane?
hydrates freshwaters wetlands oxydation in soils geological sources termites
What are two causes of nitrous oxide increase?
Fertilizer use and animal production
What is the GWP?
Global warming potential describes the relative ability, compared to carbon diozide, of a fixed mass of gas to affect rad;iative forcing and thereby the global climate over a given time period.
The GWP of carbon dioxide is always:
One
The extent to which a greenhouse gas directly contributes to radiative forcing depends on:
The quantity of gas emitted
the elapsed time before it is removed from the atmosphere
the infrared energy absorption properties of the gas.
Why is methane exert less radiative forcing than CO2 even though it’s GWP is 23?
Because it’s concentration is much less than CO2
What is the usual time horizon calculated for GWPs?
100 years
What is the CO2e?
The concentration of CO2 that would result in the same level of radiative forcing for a given type and concentration of another greenhouse gas.
What are the two bad properties of CFC’s (halocarbons (hcs))
Destroys stratospheric ozone by releasing chlorine
Strong greenhouse gas
What does ozone do in the stratosphere?
Absorbs harmful ultraviolet radiation
What does ozone do in the upper troposphere?
Its an effective greenhouse gas
What does ozone do in the troposphere?
Good - destroys harmful chemicals
What does ozone do at ground level?
It’s smog, it’s hazardous to human and plant health.
