Download greenhouses gases

4.4 Climate change
Essential idea: Essential idea: Concentrations
of gases in the atmosphere affect climates
experienced at the Earth’s surface.
The greenhouse effect is accepted scientific theory. There are certain gasses in the atmosphere cause
the sun's heat to be trapped and allow the surface of the planet to warm. Without it the surface of the
planet would be too cold for life to exist. To explain the images are quotes from NASA:
"Left: 1880-1889. Right: 2000-2009. These maps compare temperatures in each region of the world to
what they were from 1951 to 1980 ... Two-thirds of the warming has occurred since 1975, at a rate of
roughly 0.15 to 0.20 °C per decade”. These changes in temperature correlate with changes in CO2 levels.
CO2 is now at a record high of 400 ppm.
By Chris Paine
https://bioknowledgy.weebly.com/
http://climate.nasa.gov/images/ImageLarge-61.jpg
Understandings, Applications and Skills
Statement
4.4.U1
4.4.U2
4.4.U3
4.4.U4
4.4.U5
4.4.U6
4.4.U7
4.4.U8
4.4.A1
4.4.A2
4.4.A3
Carbon dioxide and water vapour are the most
significant greenhouse gases.
Other gases including methane and nitrogen oxides
have less impact.
The impact of a gas depends on its ability to absorb
long wave radiation as well as on its concentration in
the atmosphere.
The warmed Earth emits longer wavelength radiation
(heat).
Longer wave radiation is absorbed by greenhouse
gases that retain the heat in the atmosphere.
Global temperatures and climate patterns are
influenced by concentrations of greenhouse gases.
There is a correlation between rising atmospheric
concentrations of carbon dioxide since the start of the
industrial revolution 200 years ago and average global
temperatures.
Recent increases in atmospheric carbon dioxide are
largely due to increases in the combustion of fossilized
organic matter.
Threats to coral reefs from increasing concentrations of
dissolved carbon dioxide.
Correlations between global temperatures and carbon
dioxide concentrations on Earth.
Evaluating claims that human activities are not causing
climate change.
Guidance
The harmful consequences of ozone depletion do
not need to be discussed and it should be made
clear that ozone depletion is not the cause of the
enhanced greenhouse effect.
Carbon dioxide, methane and water vapour
should be included in discussions.
4.4.U1 Carbon dioxide and water vapour are the most significant greenhouse gases.
4.4.U2 Other gases including methane and nitrogen oxides have less impact.
The Earth is kept much by gases in the atmosphere that retain heat.
These gases are referred to as greenhouses gases.
The greenhouse gases that have the
largest warming effect on the Earth are:
• carbon dioxide (below)
• water vapour (e.g. clouds)
Other gases including methane and
nitrogen oxides have less impact.
nitrogen oxides are released naturally
by bacteria in some habitats and also
by agriculture and vehicle exhausts.
Greenhouse gases together make up
less than 1% of the atmosphere.
http://news.bbc.co.uk/2/shared/spl/hi/sci_nat/04/climate_change/html/greenhouse.stm
http://commons.wikimedia.org/wiki/File:GoldenMedows.jpg
4.4.U3 The impact of a gas depends on its ability to absorb long wave radiation as well as on its
concentration in the atmosphere.
impact of a greenhouse gas
Ability to absorb longwave radiation
(especially infrared/heat)
abundance in the
atmosphere
Methane has 33 times the effect
of CO2 (but is not very abundant)
rate of release
CO2 is very abundant making
up 400 ppm by volume of the
atmosphere (0.04%)
persistence
Water vapour enters the atmosphere
very rapidly, but only remains for days
whereas CO2 persists for years.
http://commons.wikimedia.org/wiki/File:GoldenMedows.jpg
4.4.U4 The warmed Earth emits longer wavelength radiation (heat).
4.4.U5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the
atmosphere.
How the greenhouse effect works
± 25% of solar
radiation is
absorbed by the
atmosphere.
1
± 75% of that solar
radiation penetrates the
atmosphere and reaches
the Earth’s surface.
2
4
3
Earth’s surface absorbs short-wave
radiation and re-emits at longer
wavelengths (as heat).
*This value, though variable, is known to be
rising; very likely the result of human activities.
85%* of heat is captured by greenhouse
gases.
5
Heat passes back, causing
warming
http://www.sumanasinc.com/webcontent/animations/content/globalcarboncycle.html
4.4.U4 The warmed Earth emits longer wavelength radiation (heat).
4.4.U5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the
atmosphere.
How the greenhouse effect works
Approx. 25% of
solar radiation is
absorbed by the
atmosphere.
1
Approx. 75% of solar
radiation penetrates the
atmosphere and reaches
the Earth’s surface.
2
4
3
The surface of the Earth absorbs shortwave solar energy and re-emits at longer
wavelengths (as heat).
*This value, though variable, is known to be
rising; very likely the result of human activities.
Up to 85%* of re-emitted heat is captured
by greenhouse gases in the atmosphere.
5
Heat passes back to the surface of
the Earth, causing warming
http://www.sumanasinc.com/webcontent/animations/content/globalcarboncycle.html
4.4.U4 The warmed Earth emits longer wavelength radiation (heat).
4.4.U5 Longer wave radiation is absorbed by greenhouse gases that retain the heat in the
atmosphere.
How the greenhouse effect works
http://www.damocleseu.org/education/Animation_about_the_greenhouse_eff
ect_182.shtml
Use the
animations/tutorials to
improve your
understanding and find
out more.
http://www.sumanasinc.com/webcontent/animations/content/globalca
rboncycle.html
http://www.sumanasinc.com/web
content/animations/content/green
house.html
http://news.bbc.co.uk/2/shared/spl/hi/sci_nat/
04/climate_change/html/greenhouse.stm
4.4.U7 There is a correlation between rising atmospheric concentrations of carbon dioxide since the
start of the industrial revolution 200 years ago and average global temperatures.
Evidence for a correlation between atmospheric carbon dioxide (CO2)
and average global temperatures
Key points
• Global temperatures
show large variations
• There is strong support
for correlation between
atmospheric carbon
dioxide and global
temperatures
http://oceanworld.tamu.edu/resources/oceanography-book/co2problem.htm
4.4.A2 Correlations between global temperatures and carbon dioxide concentrations on Earth.
To deduce historic carbon dioxide concentrations and
temperatures ice cores are drilled in Antarctic ice sheets
Vostock ice core (pictured) drilled at a Russian monitoring
station in East Antarctica is an example of an ice core.
A cylinder of ice was collected by drilling from
to the bottom of the Antarctic ice sheet. The
total length of the core was 2083 meters.
The core shows annual layers, which can be used
to date the air bubbles trapped in the ice.
Analysis of the gas content of the
bubbles gives both the
concentration of carbon dioxide in
the atmosphere and the air
temperature (from oxygen isotopes)
at the time ice was formed.
http://commons.wikimedia.org/wiki/File:GISP2_1855m_ice_core_layers.png http://en.wikipedia.org/wiki/File:GISP2_team_photo_core37.jpeg
4.4.A2 Correlations between global temperatures and carbon dioxide concentrations on Earth.
Evidence for a correlation between atmospheric carbon dioxide (CO2)
and average global temperatures
Key points
• The correlation is
supported by ice core
data over the last
400,000 years
• Temperature shows
greater variation than
CO2
• Most, but not all rises
and falls in CO2 have
correlated with
temperature rises and
falls
• The same trend has
been found in other ice
cores.
n.b. Vostock is a Russian monitoring station in East Antarctica
http://oceanworld.tamu.edu/resources/oceanography-book/co2problem.htm
4.4.A2 Correlations between global temperatures and carbon dioxide concentrations on Earth.
Evidence for a correlation between atmospheric carbon dioxide (CO2)
and average global temperatures
Key points
• The correlation is
supported by ice core
data over the last
400,000 years
• Temperature shows
greater variation than
CO2
• Most, but not all rises
and falls in CO2 have
correlated with
temperature rises and
falls
• The same trend has
been found in other ice
cores.
n.b. Vostock is a Russian monitoring station in East Antarctica
http://oceanworld.tamu.edu/resources/oceanography-book/co2problem.htm
4.4.U8 Recent increases in atmospheric carbon dioxide are largely due to increases in the
combustion of fossilized organic matter.
The link between human emissions and atmospheric levels of CO2
Key points
• There is a strong correlation
between human emissions
and atmospheric levels of CO2
• As atmospheric CO2 levels
have increased, the amount
of CO2 absorbed by carbon
sinks has increased (only
about 40% of emissions have
remained in the atmosphere)
Industrial revolution
has started
Large increases in
usage of fossil fuels
http://radioviceonline.com/wp-content/uploads/2009/11/knorr2009_co2_sequestration.pdf
4.4.U6 Global temperatures and climate patterns are influenced by concentrations of greenhouse
gases.
Global average temperatures are not directly
proportional to greenhouse gas concentrations.
Other factors, e.g. sun spot
activity, have an impact global
average temperatures
increases in greenhouse gas concentrations will likely cause:
• higher global average temperatures
• more frequent and intense heat waves
• some areas becoming more prone to droughts
• some areas more prone to intense periods of rainfall and flooding
• tropical storms to be more frequent and more powerful
• Changes to ocean currents, e.g. weakening of the Gulf Stream would
mean colder temperatures in north-west Europe
http://commons.wikimedia.org/wiki/File:Hurricane_Elena.jpg
4.4.A1 Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
Ocean acidification – the causes and effects
Research indicates that, by 2100 coral reefs
may erode faster than they can be rebuilt. This
could compromise the viability of these
ecosystems and the (estimated) one million
species that depend on coral reef habitat.
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3
F
http://youtu.be/5cqCvcX7buo
http://www.sumanasinc.com/webcontent/anim
ations/content/acidification.html
http://youtu.be/GL7qJYKzcsk
http://youtu.be/Wo-bHt1bOsw
4.4.A1 Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
Ocean acidification – the causes and effects
The ocean absorbs about 25% of
the CO2 emitted into the
atmosphere. Therefore as
atmospheric CO2 increases so do
the levels in the ocean.
Since 1800 the pH of seawater* has
fallen by 0.1 pH units. Since the pH
scale is logarithmic, this represents
approx. a 30% increase in acidity.
Estimates of future CO2 levels,
indicate that by 2100 seawater
could be nearly 150% more acidic (a
further decrease of 0.5 pH) to a
level not seen for more than 20
million years.
*seawater refers to the surface of oceans which are affected more than the depths.
http://pmel.noaa.gov/co2/files/hitimeseries2.jpg
4.4.A1 Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
Ocean acidification – the causes and effects
When CO2 dissolves in water it
forms a variety of molecules:
• dissolved free CO2
• carbonic acid (H2CO3)
• bicarbonate (HCO−3)
• carbonate (CO32−)
It is not just the creation of carbonic acid that
affects pH; when bicarbonate and carbonate
ions are formed H+ ions are released thus
decreasing the pH of seawater
Carbonate ions are not very soluble, therefore the concentration in seawater is low.
Dissolved CO2 decreases the carbonate concentration further.
http://www.pmel.noaa.gov/co2/files/oareaction_med.jpg
4.4.A1 Threats to coral reefs from increasing concentrations of dissolved carbon dioxide.
Ocean acidification – the causes and effects
At risk
Benefit
Marine calcifying species, including oysters,
clams, sea urchins, shallow water corals, deep
sea corals, and calcareous plankton.*
Photosynthetic algae and sea grasses
Need to absorb carbonate ions from
seawater to make the calcium carbonate in
their skeletons.
Low CO2 is a limiting factor for photosynthesis
The pteropod is a tiny sea creature about the size of a small pea. Pteropods are a major food source for
many animals including North Pacific juvenile salmon. The photos below show what happens to a
pteropod’s shell when placed in sea water with pH and carbonate levels projected for the year 2100.
*Shelled organisms are often keystone species and therefore the entire food web may also be
at risk.
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
4.4.A3 Evaluating claims that human activities are not causing climate change.
Many claims that human activities are
not causing climate change have been
made in the media, whether it be in
newspapers, on television or on the
internet.
It is important to realise that not all
sources are trustworthy and it is
important to know the motivation of
those publishing claims on either side of
the debate.
Last Week Tonight with John Oliver: Climate
Change Debate
http://youtu.be/cjuGCJJUGsg
http://www.skepticalscience.com/
Bibliography / Acknowledgments
Jason de Nys