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Global Change
Is the change of any
physical, chemical, or
biological properties of
the Earth
 Can include climate
change

 Change in average
weather patterns
Can include global
warming

 Warming of land, water
and atmosphere
Solar (ultraviolet)
radiation either bounces off
the stratosphere or enters
the troposphere
 Solar radiation heats the
planet’s surface and that
heat is re-emitted (infrared)
 Infrared is either
absorbed by greenhouse
gases or is lost to space

Is caused by gases in the
atmosphere that absorb
heat and re-emit it
 Traps heat in the
troposphere and increases
the planet’s surface
temperature
 Gases can be measured in
greenhouse warming
potential

 How much a molecule can
contribute to global
warming over 100 years

Water Vapor
 Most abundant natural
greenhouse gas




Carbon dioxide
Methane
Nitrous oxide (N2O)
Chlorofluorocarbons (CFCs)
 Solely manmade
Particulates are not a gas,
but they do contribute to the
greenhouse effect

Volcanic eruptions produce CO2
and particulates
 Decomposition of organic matter
produces methane and/or CO2
 Denitrification (part of nitrogen
cycle) produces nitrous oxide (N2O)
 Evaporation of water into the air
produces water vapor


Fossil Fuels
 Production and burning release CO2
 Can also produce methane and
particulates

Agriculture
 Fertilizers add nitrogen to make
N2O
 Decomposition of organics releases
methane

Landfills
 Decomposition of organics releases
methane

Chemicals
 CFCs deplete ozone and retain heat

Deforestation
 Removes trees that absorb CO2
This can be shown by
determining historical gas
concentrations and temperature
and charting them together
 Intergovernmental Panel on
Climate Change (IPCC) was
formed to track these changes

 Scientists from UN and World
Meteorological Organization
Discovered when
atmospheric CO2
concentration monitoring
began in 1958 on Mauna
Kea
 Drops in spring when
photosynthesis increases
and increases in fall when
leaves die
 Has shown an overall
increase since monitoring
began

Projecting future increases in CO2
From 1960 to 2010 CO2 has increased from 320 to
390 ppm
 Average annual increase over 40 years?
390 ppm – 320 ppm = 70 ppm
70 ppm CO2/40 years = 1.75 ppm CO2/year
 If rate of CO2 increase is 1.4 ppm/year, what will CO2
concentration be in 2100?
1.4 ppm/year x 90 years = 126 ppm
126 ppm + 390 ppm = 516 ppm CO2


What will the CO2 concentration be in 2100 at a
faster rate of 1.9 ppm/year?
1.9 ppm/year x 90 years = 171 ppm
171 ppm + 390 ppm = 561 ppm CO2

Vary greatly among
nations

 Developed nations produce
the most CO2
Should be examined on a
nationwide and per-capita
basis
 Are changing rapidly as
populous nations like China
and India develop industry
and infrastructure

Have been directly
measured since the 1880s
 Have increased since
these measurements
began
 2000-2009 were 9 of
the 10 hottest years on
record

Indirect measurements
include species
composition and chemical
analysis of ice cores
 Species composition of
foraminifera changes as
the water temperature
changes

 When they die their
skeletons become part of
ocean sediments
Air bubbles are trapped in
ice in glaciers and ice
shelves
 These tiny samples
provide information about
atmospheric gases and
temperature

 Oxygen isotopes appear
more frequently in warmer
temperatures
A single core can show
500,000 years of data

Increased solar
radiation would increase
heat when the sun shines
 Increased greenhouse
gases would increase heat
when the sun isn’t shining
 Patterns of heating
show increases that are
not correlated to the sun
shining

Global warming is a
confirmed phenomenon
 What remains to be
seen is exactly how
much the temperature
will rise
 Models can help us
predict what will
happen


Positive feedback
 Faster decomposition
from warmer
temperatures adds more
CO2
 Melting ice exposes
darker soil which retains
heat and increases
melting

Negative feedback
 Increase in CO2 causes more
plant growth, and more
plants reduce CO2
 Increase in cloud cover
causes more solar reflection,
and temperatures drop
Melting polar ice caps and
glaciers

 Adds large amounts of fresh
water to the oceans
 Could expose new sources
of fossil fuels

Thawing permafrost
 Releases methane and CO2
 Could make land usable in
new ways
Change in precipitation
patterns

 More water vapor is added
to the atmosphere
 Some areas get more,
others get less

Rising sea levels
 Endanger low-lying
human settlements
through flooding and
polluting groundwater

Increase in heat waves
 Can cause drought and
increased energy use for
cooling
 Can increase forest fires

Decrease in cold spells
 Increase in tropical pests
 Could be good for
agriculture

Increased storm intensity
 Warm air holds more water

Change in ocean currents
 Influx of fresh water could
affect how heat is distributed
Change in distribution and
extinction of organisms

 Range of cold-tolerant
organisms will decrease and
heat-tolerant organisms will
expand
 Reproduction could be affected
Increase in tropical diseases and
other health problems

 Mosquito range and population could
increase, carrying West Nile and
malaria further
 Increased heat stroke, asthma, and
allergies
Change in agriculture and
recreation

 Increased land for agriculture
 Change in winter tourism
Addresses climate
change at the
international level
 Asked nations to
reduce greenhouse gas
emissions to 5.2% below
1990 levels by 2012

 US 7%, EU 8%, Russia
0%, developing
countries 0%
Involves taking CO2 out
of the atmosphere
 Storing carbon in soil or
deep underground
 Absorption by plants
