Download Climate Science Lecture 2

Climate Science
Lecture 2
1) Overview of the Climate System
a) Components of the Climate
i) Air, water, ice, land, and vegetation
ii) These components are interrelated
through numerous “internal” processes –
change one and others change as well
(1) Winds, precipitation, water freezing to
ice, ice melting, water evaporating
into the air, running water erodes
land, cold temps may kill vegetation,
etc.
b) Forcing – term referring to the cause of
changes to the system (one or most of the
components) generally “external”
c) Response – term referring to effect that the
Forcing produces – “internal”
2) Agents of Climate Change
a) External Forcing
i) Tectonic Processes – slow of movement
of the Earth’s surface due to internal heat
(1) Mountains growing – Oceans created
and destroyed – Relocation of land
mass
(2) Rate – millions of years
ii) Earth’s orbital changes – variations in
Earth’s position relative to the Sun
(1) Causes changes in the radiation
received and absorbed by Earth
(2) Rate - 10s to 100s of thousands of
years
iii) Variations in the Sun’s energy output
(1) The Sun has slowing strengthened
since it formed 6 BYA
(2) Solar output variation also occur a
few years to decades scale
(a) Sun spot cycles (11 years)
b) Internal Forcing
i) Anthropogenic – Human caused climate
change
(1) Farming changes to land and
vegetation
(2) Industry changes the air and water
(3) And most other activities impact the
climate system as well
3) Climate System Responses
a) Response time – how long before you react
and adjust to a change
i) Human responses
(1) Fast – you touch a hot object – less
than 1 second
(2) Slower – stay out in the sun – sunburn
shows in minutes to hours
(3) Very slow – exposed to flu –
symptoms in days
(4) Extremely slow – long term expose to
carcinogens – cancer in years to
decades
ii) Climate response
(1) Atmosphere – hours – sun rises and
sets
(2) Land – hours to months – soil slowly
warms in spring before planting
(3) Ocean surface – days to months
(4) Vegetation – day to centuries
(5) Sea Ice – weeks to annual cycles
(6) Mountain glaciers – decades to
centuries
(7) Deep ocean – centuries to millennia
(8) Continental glacier (ice sheets)
centuries to 10s of millennia
4) Time scale of forcing vs response
a) Slow force – fast response: track together –
slow offensive player, fast defensive player
b) Fast force – slow response: takes a long time
to catch up – fast offensive player, slow
defensive player
c) Equal rates for forcing and response – even
matched players
d) Out of phase effect
5) Feedback – force A causes response B, which
causes another force C, and A responds ,etc.
a) Positive: if A and C cause similar response
then B keeps moving in one direction
i) Cold temp cause snow – snow reflects
suns heat – making it colder – more snow
b) Negative: when C cause opposite effect in A,
thereby changing direction of B
i) Warm temps cause evaporation –
evaporation increases water vapor in air –
more water vapor results in more clouds –
more clouds lower temp