Transcript Climate Change

Climate Science
This presentation is designed for those who wish to provide a reasoned
argument against the ever proliferating confusion over climate science.
Newer versions of this presentation and others can be found at:
www.vicphysics.org Follow the link from the ‘Climate Change’ link on the
‘Home’ page.
Be sure to look at the ‘Notes pages’ (below) for added comments to help in
presenting and for more information and sources. Please feel free to email me
with suggestions for improvements or useful comments.
This presentation is designed for around an hour (or more with expansion of
some of the points)
Latest version 23 Feb 2010
Keith Burrows
Science Teachers for Climate Awareness
Countering Climate
Confusion
What to say to ‘sceptics’
Download from www.vicphysics.org
CCC –Climate
Main Points
Countering
Confusion
 The basic reason for concern is the fundamental
science (not rising temperatures or sea levels).
– CO2 captures heat radiation from the ground and
sends it back.
– The greenhouse effect is well understood. It is crucial
to life on Earth.
– We know we are increasing the greenhouse effect.
The question is by how much and what will happen.
– We know the Earth is capable of wild swings of
climate from ‘Snowball Earth’ to ‘Hothouse Earth’.
CCC – Basic science
 First counter: Why won’t adding more CO2 to
the atmosphere increase the greenhouse
effect?
 Here’s a partial list...
Some scientific bodies who have issued statements stressing the
need for action on climate change – USA only
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National Academies of Science
National Research Council
American Association for the Advancement of Science (AAAS)
National Oceanic and Atmospheric Administration (NOAA)
National Center for Atmospheric Research (NCAR)
NASA's Goddard Institute of Space Studies (GISS)
American Institute of Physics
Woods Hole Research Center
Union of Concerned Scientists
Federal Climate Change Science Program
American Geophysical Union
Geological Society of America
American Chemical Society - (world's largest scientific organization)
Federal Climate Change Science Program - commissioned by Bush!
American Association of State Climatologists
US Geological Survey
Environmental Protection Agency (EPA)
Pew Center on Climate Change
Some scientific bodies who have issued statements stressing the
need for action on climate change – Rest of World
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UN Project on Climate Variability and Predictability
United Nations Framework Convention on Climate Change (UNFCCC)
United Nations Environment Program
World Meteorological Organization
International Council on Science
The Royal Society (UK)
The Institute of Physics (UK)
Canadian Meteorological and Oceanographic Society (CMOS)
Geological Society of London
The Australian Academy of Sciences
The Institution of Engineers Australia
The Australian Meteorological And Oceanographic Society
• … and many more!
CCC – Basic science
 Second counter:
 It is easy to create confusion, about climate
science, but much harder to clarify it.
 Denier arguments often ‘look reasonable’, but
always fall down on close inspection. But all
they need to do is create confusion.
 This is strong evidence that climate change
is serious!
CCC – Risk management
 Third major counter:
• Would you get on this aeroplane if 1
out of 10 engineers found
dangerous cracks in the wings?
• How about if 9 out of 10 engineers said
there were dangerous cracks in the
wings but 1 said they didn’t matter?
• That’s about the proportion of
climate scientists saying climate
change is dangerous!
• That’s about the proportion of
climate scientists saying climate
change is dangerous!
Actually it is more like over 95%
“This image was digitally altered!”
CCC – Risk Management
 Normally we don’t take risks where lives are
at risk.
CCC – Risk Management
www.gregcraven.org
CCC – Risk Management
www.gregcraven.org
CCC – Risk Management
Disaster!
CCC – Risk Management
“What if
we create
a better
world and
it turns
out we
didn’t
need to?”
CCC – Risk Management
Do the ‘sceptics’ ask themselves this question?
www.gregcraven.org
CCC – Risk management
 Third major counter:
What if you are wrong?
Genuine sceptics will answer this by saying
we should take precautions.
Deniers simply don’t seem to hear the
question!
‘Climate sceptics’ and ‘climate deniers’
Climate sceptics
 Scepticism is an important part of science. Scientists
always try to question and test their theories.
 Scientific sceptics discuss their questions with other
scientists through the peer reviewed journals.
Climate deniers
 Deniers take the supposed ‘debate’ to the public –
inappropriately. They avoid discussions with the
scientific community.
 Deniers express no doubt about their position – or they
would have to take action in case they are wrong.
Countering Climate Confusion
 So:
 Basic science says adding CO2 must warm the
Earth.
 Confusion is easy, but hides a potential
catastrophe.
 Why on Earth would we risk the only planet
we have?
 A little more on each of these...
CCC – Some basic science
 Why is the Earth at just the right temperature
for us?
The Big Picture
The Big Picture
EARTH:
Atmosphere:
Mean temperature:
N2 , O2 , H2O and a little CO2
+15oC
Just right!
Why?
CCC – Some basic science
Earth’s energy balance
So what determines the Earth’s temperature?
 The balance between the energy coming in
 ... and that going out.
CCC – Some basic physics
 Earth’s energy balance
– Two simple laws of physics
enable us to figure out the
energy balance:
 The Stefan-Boltzmann law...
= εσT4
 Wien’s law... λmax = 0.0029/T
I
– S-B just tells us how much heat
a hot object radiates.
– Wien tells us what sort of
radiation it will be.
(but fortunately others have done the
hard work for us!)
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
“The Earth’s
average
temperature
should be about
–18oC”
?
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
“Ah! The
atmosphere
must be
trapping the
heat”
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
“But Oxygen
and Nitrogen
can’t absorb the
infrared
radiation”
?
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
“It must be the
water vapour
and carbon
dioxide!”
CCC – Some basic physics
 Svante August Arrhenius worked it out in 1896
“Together they
absorb heat and
re-emit enough
back to Earth to
raise the
temperature by
+33degrees!”
“Doubling CO2 should raise the
Earth’s temperature about 5°C”
CCC – Some basic physics
 Earth’s energy balance:
– Not all the IR radiation from the surface
escapes immediately...
– or the average temperature would be a
freezing –18°C
– No liquid water or clouds
– And no life!
 This is very well established physics!
CCC – Some basic science
So how does the atmosphere keep us
+33°C warmer?
CCC – Some basic science
 How do air molecules ‘trap’ the IR radiation?
Oxygen (O2): 21%
Nitrogen (N2): 78%
Water vapour (H2O): 0% – 1%
Carbon dioxide (CO2): 0.04% (was 0.03%)
CCC – Some basic science
 Nitrogen (N2) and oxygen (O2) molecules:
 Two atoms ‘tightly bound’
CCC – Some basic science
 Water (H2O) and carbon dioxide (CO2)
molecules:
 Three atoms ‘loosely bound’
CCC – Some basic science
 Nitrogen and oxygen molecules:
 Light ‘photons’ (visible and IR) go right
through N2 and O2
CCC – Some basic science
 Water and carbon dioxide molecules:
 Infrared photons get absorbed by H2O and CO2
molecules (and give them energy)
CCC – Some basic science
 Water and carbon dioxide molecules:
 The H2O and CO2 don’t keep the energy...
 they ‘re-radiate’ it.
CCC – Some basic science
 Some of this re-radiated IR goes back down and
warms the surface – a little like a greenhouse...
 The so called “Greenhouse Effect”
 This keeps the Earth at a warm +15oC (average)
instead of that freezing –18oC
Countering Climate Confusion
 In other words we understand the basic
science very well.
 The two key questions are:
 By how much will our CO2 emissions
increase the temperature?
 What will be the effect of that increase?
Countering Climate Confusion
 By how much will our CO2 emissions increase
the temperature?
 This is complex, but there are a number of
different approaches–
–
–
–
–
Look at the physics (climate models)
Look at the past (palaeoclimate)
Look at the effect of recent changes (volcanoes etc)
Measure it ...
CCC – Some basic science
 Car
+70 ppm
+0.6°C
1°C per 50 years
CCC – Some basic science
 But it is a lot more complicated than that!
– Thermal inertia (delayed action)
– Non-linear problem (2 + 2 X
= 4!)
– Feedback effects (positive and negative)
 This is the big one!
 But most reliable estimates are around 2°C –
5°C per doubling of CO2 Most likely ~3°C
 Deniers have to find ways to claim that this is
less than 1°C! (Usually by dodgy calculations)
CCC – Some not so basic science
 This is where computer models come in
handy!
IPCC
(IPCC graph)
The basic data needed is measured in various ways and is well known.
Notice that overall, incoming equals outgoing (342 = 107 + 235). Also, that
large amounts of energy are absorbed and re-radiated by greenhouse gases.
CCC – Some not so basic science
 Scientists put all the laws of physics and
chemistry into computer models which can do
the vast numbers of calculations needed.
 Some of the basic equations:
CCC – Some not so basic science
 The models divide the atmosphere and ocean
into cells about 1 km deep
CCC – Some not so basic science
 Remember this:
 Economic computer models take human
guesses about other human’s behaviour.
 Scientific models take the very well known
laws of physics and chemistry and apply
rigorous maths.
 There is a VERY BIG difference between
economic and scientific computer models!
 And climate models can be tested...
CCC – Some not so basic science
 Results of models:
CCC – Some not so basic science
 Ignoring our emissions:
Cooling
Wrong!
CCC – Some not so basic science
 Including our emissions:
Warming
Correct!
CCC – Some not so basic science
 This is one reason climate scientists
are confident that they have the
basic science correct.
 And those models predict more
warming: 3°→ 5°C this century...
 unless we cut emissions!
Countering Climate Confusion – Recap
 The basic reason for concern is the fundamental
science (not rising temperatures or sea levels).
– CO2 captures heat radiation from the ground and
sends it back.
– The greenhouse effect is well understood. It is crucial
to life on Earth.
– We know we are increasing the greenhouse effect.
The question is by how much and what will happen.
– We know the Earth is capable of wild swings of
climate from ‘Snowball Earth’ to ‘Hothouse Earth’.
Palaeoclimate Confusion
 Plimer says “the climate
has always changed” –
we just have to get used
to it.
“If we humans, in a fit of
ego, think we can change
these normal planetary
processes, then we need
stronger medication.”
Palaeoclimate Confusion
In the last 500 million years the climate has swung between
‘Hothouse Earth’ and ‘Snowball Earth’
Hothouse Earth
Snowball Earth
Palaeoclimate Confusion
Palaeoclimate Confusion
Palaeoclimate Confusion
 The last ‘interglacial’ – similar
to current climate.
 Maybe ~2°C warmer than last
century average...
July
2009
“Paul Blanchon's
team at the National
Autonomous
University of Mexico
in Cancun has been
studying 121,000
year old coral reefs in
the Yucatan
Peninsula, formed
during the last interglacial period when sea level peaked at around
6 metres higher than today. His findings suggest that at one point
the sea rose 3 metres within 50 to 100 years.”
Temperatures in that interglacial were only a couple of degrees warmer than the 20th C.
Climate science
 Sea level
in last
interglacial
12 m
higher
than
today
Palaeoclimate Confusion
 Climate change in the time of human
civilization has been very minor ±½°C.
 Talk of ‘warm Greenland’ is just a distraction.
 The climate change we are looking at is far
more drastic than anything humans have
experienced.
Palaeoclimate Confusion
Pliocene
+3°C
Palaeoclimate Confusion
Pliocene
Sea levels
between
25 and 75
metres
higher
than today
The rest of these slides are a selection from
the “What’s wrong with deniers?”
presentation.
(MisconceptionsKB2.ppt)
Download from www.vicphysics.org
Present Climate Confusion
“The UN is using the
global warming
scare in order to
impose world
government”
Science Teachers & Climate Change
 Media coverage
Science Teachers & Climate Change
 Media coverage:
Science Teachers & Climate Change
 Even in the
more
‘reputable’
press there
is support
for the
‘sceptics’
1-1 “It is getting cooler” “the warming has stopped”
“Lord Monckton of Brenchley”
Only 7 years!
1-1 “It is getting cooler” “the warming has stopped”
“Lord Monckton of Brenchley”
1-1 “It is getting cooler” “the warming has stopped”
40 years
Typical yearly
variation
compared to
yearly warming
trend
CLIMATE
CHANGE
WEATHER
Which is why
we notice the
weather more
than climate
change!
Many have suggested the cool spell in the N. hemisphere suggests GW has stopped.
What they don’t realise is that it was a ‘local’ effect. The rest of the world MORE THAN
MADE UP for their cooling. But many deniers live in the cool regions!
1-1 “It is getting cooler” “the warming has stopped”
 For this reason we should look at decade trends or
long term averages
CSIRO
graph
11 year
averages
1-1 “It is getting cooler” “the warming has stopped”
 For this reason we should look at decade trends or
long term averages
Which is more likely?
OR
But temperatures are falling
while CO2 is rising!
3-3 “Correlation between temperature and CO2 levels.”
Typical ‘denier’
graph:
• Short term 19982008
• Starts on high ends
on low
• Deceptive scale
(looks like more
than 10 years)
• Looks ‘official’
3-3 “Correlation between temperature and CO2 levels.”
3-4 “Climate science isn’t settled”
 True! Science is never ‘settled’ and climate activists
should stop saying it is.
 The point is that there is a large amount of evidence to
suggest that we are dangerously interfering with the
climate.
 Science always works by different groups advocating
different approaches and often getting different results.
 By continually checking and re-checking, eventually
results begin to agree and consensus emerges.
 There is not yet a complete consensus, but there IS
strong opinion that we are changing the climate
dangerously.
Today
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