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NMSU Rainfall
-1
0
1
2
3
4
5
6
7
8
9
10
1 20 39 58 77 96 115 134 153 172 191 210 229 248 267 286 305 324 343 362
Days since Jan 1
Cumulative Rainfall (Inches)
2006200520042003
Climate vs. Weather
0
20
40
60
80
100
120
1 20 39 58 77 96 115 134 153 172 191 210 229 248 267 286 305 324 343 362
Max Temp. (°F)
Days since Jan 1
2006200520042003
Temp
Days since Jan 1
Climate System: 5 parts
• Atmosphere• Ocean• Cryosphere (ice)• Lithosphere• Sun and internal earth heating
Climate System
• Atmosphere– Nitrogen N2 78%
– Oxygen O2 21%
– Argon Ar 0.93%
– Carbon dioxide CO2 0.035%
– Other minor gases 0.035%
Cryosphere: ICE
• Melting ice increases ocean volume
• Sea level was 130 m (425 feet) lower during last ice age (18,000 years ago)
• Ice reflects solar energy: albedo
Lithosphere
• Mountains influence weather• Arrangement of continents affects ocean
currrents• Volcanism affects composition of
atmosphere
Solar energy input to Earth’s surface is342 W/m2.
Heat flowing out of Earth’sdeep interior is only 0.06 W/m2.
Greenhouse Gases
• CO2, H20 and methane (CH4):
• Absorb and re-radiate radiation• Insulates and raises Earth temperature
Feedback enhances warming
• Positive Feedback: – Amplifies changes in the system.
– Temperature increase decreases Earth’s albedo by reducing snow and ice cover
Climate Change
Understanding Natural Climate Variability:
Use the geologic record to understand Earth Climate in the past
(Uniformitarianism)
Long-term change can be assessed from ice cores, which record annual cycles of ice formation from snow.
* Cycles can be counted back like tree rings to create a long term record.
* Ice layers trap atmospheric gas, contain isotopic record of temperature change.
GEOLOGIC RESERVOIRS
Fossilorganiccarbon
Rockcarbonates
Fossil-fuel
burning(5.3 Gt/yr)
OCEAN
Cement production (0.1 Gt/yr)
Land-use change:
deforestation,agriculture(1.7 Gt/yr)
Land uptakeBy new plantgrowth(1.9 Gt/yr)
Ocean uptake by air-sea gas
exchange(1.9 Gt/yr)
Terrestrial biosphere
LAND
ATMOSPHERE
The influence of Carbon on climate change
GEOLOGIC RESERVOIRS
Fossilorganiccarbon
Rockcarbonates
Fossil-fuel
burning(5.3 Gt/yr)
OCEAN
Cement production (0.1 Gt/yr)
Land-use change:
deforestation,agriculture(1.7 Gt/yr)
Land uptakeBy new plantgrowth(1.9 Gt/yr)
Ocean uptake by air-sea gas
exchange(1.9 Gt/yr)
Terrestrial biosphere
LAND
ATMOSPHERE
Human activities releasea total of 7.1 Gt of carbon into the atmosphere each year.
New plant growth andair-sea gas exchangeremove 3.8 Gt/yr,…
…yielding a netatmosphericincrease of3.3 Gt/yr.
Tem
pera
ture
rela
tive t
o p
resen
t clim
ate
(°C
)
Thousands of years before presentR
ela
tive c
arb
on
dio
xid
e a
nd
meth
an
e c
on
cen
trati
on
s
High
Low
Key:TemperatureCO2
Methane
There is a decline in both temperature and greenhouse gas concentrations during glacial periods… …and a rapid
rise duringdeglaciation.
Climate has been relatively warm andstable during the last 10,000 years.
Years
Temperature
CO2 concentration
The 20th-century is clearly anomalous when compared with the last millennium.
Nort
hern
Hem
isp
here
tem
pera
ture
an
om
aly
(°C
)
CO
2 c
on
cen
trati
on
(p
pm
)
Years
Temperature
CO2
concentration
Glo
bal te
mp
era
ture
an
om
aly
(°C
)
A recent warming trend correlateswith the increase in CO2.
CO
2 c
on
cen
trati
on
(p
pm
)
….and Estimated Average Surface Temperatures for Those Scenarios
Uncertainty envelope due to lack of knowledge of climate system
Why is Global Warming ignored?
• Not enough evidence?• Better things to spend money on?• Cutting emissions will hurt the economy
• The EFECTS of climate change might be distant and uncertain
• The COSTS of curbing greenhouse gases are immediate and substantial!
Global Warming
• Small steps can reduce carbon emissions
• These are affordable and multiplied by 100,000,000s of people can be significant
• CO2 is a small part of the atmosphere
• Small increases have huge effects• Greenhouse gases keep earth hot• Natural changes in climate occur• Recent changes correlate to human activity• Changes in lifestyle can avoid catastrophe