climate change – new science – old arguments. overview some old science the big experiment …...
TRANSCRIPT
Climate Change
– New Science– Old Arguments
Overview
Some old science The big experiment … The Earth’s climate Is the Earth warming? Does it matter? What can we do about it?
So what is the -
‘Greenhouse effect’ ?
It’s all just a bit of physics!
Actually it started with
Joseph Fourier (1820’s)
John Tyndall (1860’s)
Svante Arrhenius (1890’s)
So what is the (Earth’s) ‘Greenhouse effect’ ?
Climate Science 101
“The Earth should be a lot colder than it is”
Joseph Fourier ~1820
Climate Science 101 Fourier used basic physics to calculate that
the Earth ought to be a frozen snowball!
Climate Science 101
He realised that somehow the atmosphere must be trapping heat
Climate Science 101
Tyndall found it was the water vapour and carbon dioxide gases in the air
John Tyndall ~ 1860
Climate Science 101
Earth’s energy balance Svante August Arrhenius worked it out in 1896
Earth’s energy balance Svante August Arrhenius worked it out in 1896
“The Earth’s average temperature should be about –18oC”
?
Climate Science 101
Climate Science 101
Earth’s energy balance Svante August Arrhenius worked it out in 1896
“CO2 and H2O absorb heat and send enough back to Earth to raise the temperature by
+33 degrees!”
Climate Science 101
Earth’s energy balance Svante August Arrhenius worked it out in 1896
“So what will all the CO2 we are putting in the atmosphere do?”
?
Climate Science 101
Earth’s energy balance Svante August Arrhenius worked it out in 1896
“If we double the CO2 it could raise the temperature by about 5 degrees!”
That’s not all that far off modern IPCC estimates of 2°C – 5°C
“That will make Sweden warmer – good !”
Climate Science 101
The Earth’s temperature is determined by the balance between incoming solar radiation from the Sun…
The Earth’s temperature is determined by the balance between incoming solar radiation from the Sun…
and outgoing ‘heat’ radiation into space
Climate Science 101
A little physics Earth’s energy balance
– Two simple laws of physics enable us to figure out the energy balance: The Stefan-Boltzmann law...
I = εσT4 Wien’s law... λmax = 0.0029/T
– S-B just tells us how much heat a hot object radiates.
– Wien tells us what sort of radiation it will be.
Don’t panic!
(fortunately others have done the hard work for us!)
Climate Science 101
The H2O and CO2 in the atmosphere trap some of the IR and so the Earth heats up until it emits enough IR...
… to balance the incoming solar radiation
At present this happens at around 15oC
If less energy escapes than comes in we get warmer.
Climate Science 101
Climate Science 101
Even though the H2O and CO2 are only a tiny proportion of the air, they absorb the outgoing infrared (‘heat radiation’)
But how can CO2 which is only 0.04% of the atmosphere do that? (Or 390 ppm)
Simple: Nitrogen and Oxygen do not absorb infrared (IR) while H2O and CO2 do.
Climate Science 101
(There are good physics answers to that question but ...)
Here’s a simple analogy: Water allows all visible light through But ink blocks it ....
Climate science
300 ppm (or 0.03%) might not sound like much, but here is the effect of adding 300 ppm of ink to a glass of water:
Climate Science 101
The water is like the atmosphere – it has no effect on the light
The ink absorbs visible light just like the carbon dioxide absorbs infrared light
If we could ‘see’ in infrared the atmosphere would look quite opaque!
The atmosphere traps heat and warms the Earth
Climate Science 101
Climate Science 101
This is a like a greenhouse...
So it is called the “Greenhouse Effect” It keeps the Earth at a warm +15oC (average)
instead of that freezing –18oC
Greenhouse Effect = +33oC
Our place in space
Steady temperature:
Heat in (from you)
=
Heat out (IR radiation)
Climate Science 100
More blankets …
Harder for heat to escape …
You get warmer until …
heat in (from you)
equals heat out (IR radiation)
Climate Science 100
+33 degrees
+33 + ? degrees
The Biggest Experiment
on Earth…ever!
The BIG Experiment
Started 200 years ago Global scale Involves all of us Costs a fortune (By-passed the ethics committee) Results are coming in fast! Hypothesis is being confirmed (Could be some unintended consequences) What is it? . . . .
The Big Experiment is... … the release of the carbon stored by solar
energy over 100 million years ...
(In the Carboniferous era from around 300 Mya to 200 Mya)
Solar energy converted CO2 in the air into plant growth (forms of carbon)
The Big Experiment is... … the release of the carbon stored by solar
energy over 100 million years …
in only centuries
That is, a MILLION times faster.
We have to ask whether it might have an effect!
ie. 600,000,000,000 tonnes
The Big Experiment We have increased atmospheric CO2 by 40%
and now we are waiting to see what the climate will do!
The Big Experiment
Is the Earth warming?
2010
”But the warming has stopped”
Overview
Climate science 101 – Greenhouse effect The big experiment …
The Earth’s changing climate Is the Earth warming? Does it matter? What can we do about it?
Earth’s climate – looking at the past
Climate change IS natural … BUT!
Hothouse Earth
Snowball Earth
In the last 500 million years the climate has swung between ‘Hothouse Earth’ and ‘Snowball Earth’
Earth’s climate
Earth’s climate
The Earth: 500 million years ago to
20 million years ago
Hothouse Earth
Snowball Earth
Earth’s climate
20 Mya
Earth’s climate
The Earth 20 million years ago About 2oC or 3oC warmer than today Sea about 50 metres higher
Earth’s climate
The Earth today
Earth’s climate
Do we really want to go here?
Earth’s climate
The Earth 18 thousand years ago About 5oC colder than today Sea about 100 metres lower
Earth’s climate
Today
Earth’s climate changes – but why?
Over millions of years: Continental movement Changing atmosphere – plant life Changes in greenhouse gases Meteor impacts Massive volcanic activity Changes in the Earth’s orbit Changes in the Sun’s output
Earth’s climate changes – but why?
Over thousands of years (the last 1 million): Volcanic activity (small) Changes in the Earth’s orbit Changes in the Sun’s output Changes in greenhouse gases
Earth’s climate changes – but why?
Earth’s climate
Earth’s climate
Earth’s climate
The orbital wobbles triggered the changes The carbon dioxide AMPLIFIED them …
Earth’s climate and Carbon Dioxide
Solar warming
More carbon dioxide into atmosphere
Higher temperaturesMore
greenhouse warming from carbon dioxide
Positive feedback!
Earth’s climate – looking at the past
The last ‘interglacial’ – similar to current climate.
Maybe ~2°C warmer than last century average...
last interglacial period when sea level peaked at around 10 metres higher than today. His findings suggest that at one point the sea rose 3 metres within 50 to 100 years.”
“Paul Blanchon's team at the National University of Mexico has been studying 121,000 year old coral reefs in the Yucatan Peninsula, formed during the
Temperatures in that interglacial were only a couple of degrees warmer than the 20th C.
July2009
10 m higher than today
Sea level in the last inter-glacial
Today
Earth’s climate – looking at the past
Climate change in the time of human civilization has been very minor: ±½°C.
Talk of ‘warm Greenland’ or the ‘Little Ice Age’ is just a distraction.
The climate change we are facing is far more drastic than anything humans have experienced.
Earth’s climate – looking at the past
2010
Earth’s climate – looking at the past
+3°C
Pliocene
Earth’s climate – looking at the past
Pliocene
Sea levels between 25 and 75 metres higher than today
Earth’s climate
There is much more! Some past abrupt
climate changes have been linked to sudden releases of greenhouse gases
National Academies Press (USA)
Earth’s climate
Many extinction events followed a rise in CO2 levels
Not ‘proof’, but surely cause for concern!
Adapted from: Under a Green Sky – P.Ward, Smithsonian
Overview
Climate science 101 – Greenhouse effect The big experiment … The Earth’s climate
Is the Earth warming? Does it matter? What can we do about it?
really
^
‘Sceptics’ and ‘deniers’
Scientists are always sceptical If you can show a theory is wrong that is great! “If the facts change, scientists change their
minds” POLITICS: Chose only the facts that ‘prove’ your case … and stick to them whatever! (Look at what happens if a politician changes her mind!)
“Climate-change denial could have disastrous consequences if it delays global action to cut carbon emissions. Denialism is gaining popularity because people have difficulty differentiating deniers’ twisted arguments from the legitimate concerns of genuine sceptics.”
Christopher Monckton of Brenchley’s version of temperature trends
Title Let’s put Monckton’s red line on the
NASA graph
Typical Bolt:
“In fact, if Gillard shut down our economy completely and shot every burping cow , the temperature by 2100 would fall just 0.01 degrees. All pain, zero gain.”
Herald-Sun 12 March 2011
‘Sceptics’ and ‘deniers’
…if nobody else did anything!
“In the end, he found Bolt's writings were calculated to offend and inflame negative views in his readers, omitted crucial information that would have countered the arguments he was making, and were full of errors. He also found that they were reasonably likely to offend, insult, intimidate and humiliate …”
The Age Editorial 30 Sep 2011 (The “White Aboriginal” case)
‘Sceptics’ and ‘deniers’
Satellites can measure the heat escaping to space …
Low radiation High radiation
Is the Earth warming?
Is the Earth warming?
… and IT IS LESS THAN THAT COMING IN from the Sun!
The Earth must warm until they balance!
Reflected visible radiation Emitted IR radiation
Is the Earth warming?
Is the Earth warming? The Ocean
It is the heat in the ocean that drives the weather
More heat
warmer water
more evaporation
more water vapour
more storms and rain
Is the Earth warming? Storms
Pakistan 2010
Beijing June 2011
China August 2010
Cyclone Yasi Feb 2011
Cyclone Yasi Feb 2011
Cranbourne
Brisbane
Ethiopia
Russia
Is the Earth warming? Global temperatures
Is the Earth warming? Glaciers
Is the Earth warming? Antarctica
Is the Earth warming? Greenland
Is the Earth warming? Arctic Sea Ice
Arctic Sea Ice September 2011
Is the Earth warming? Arctic Sea Ice
Is the Earth warming? Sea levels
Is the Earth warming? Sea levels
Is the Earth warming? Floods
“The year 2010 was one the worst years in world history for high-impact floods. But just three weeks into the new year, 2011 has already had an entire year’s worth of mega-floods. “ – Meteorologist Jeff Masters
THE world has just five years to make ''urgent and radical policy changes'' or lock in dangerous climate change, the world's leading energy agency has warned, sparking a debate about whether Australia should shift to gas or renewable energy.
Agency chief economist Fatih Birol said if by 2017 there is not a start to major new clean infrastructure investments ''the door to 2 degrees will be closed''.
''I am very worried,'' he said, ''if we don't change direction now on how we use energy, we will end up beyond what scientists tell us is the minimum. The door will be closed forever.''
We find that in the set of scenarios with a ‘likely’ (greater than 66%) chance of staying below 2 °C, emissions peak between 2010 and 2020 and fall to a median level of 44 Gt of CO2 equivalent in 2020 (compared with estimated median emissions across the scenario set of 48 Gt of CO2 equivalent in 2010). Our analysis confirms that if the mechanisms needed to enable an early peak in global emissions followed by steep reductions are not put in place, there is a significant risk that the 2 °C target will not be achieved.
"The bad news just got worse: A new study finds that reining in greenhouse gas emissions in time to avert serious changes to Earth's climate will be at best extremely difficult. Current goals for reducing emissions fall far short of what would be needed to keep warming below dangerous levels, the study suggests. To succeed, we would most likely have to reverse the rise in emissions immediately and follow through with steep reductions through the century. Starting later would be far more expensive and require unproven technology".
Nature Climate Change | Letter Emission pathways consistent with a 2 °C global temperature limit Joeri Rogelj et.al. 23 October 2011
The Age 5 Nov 2011
Overview
Climate science 101 – Greenhouse effect The big experiment … The Earth’s climate Is the Earth warming?
Does it matter? What can we do about it?
Sea level rises drown all our major coastal cities
Droughts and floods ruin agricultural land and cause famine
Biodiversity lost as species fail to adapt Water supplies (from Himalayan glaciers) to
the great Asian food bowl dry up Climate refugees overwhelm developed
countries
Does it matter?
Does it matter?
“We have already overstepped three of nine planetary boundaries and we are at grave risk of transgressing several others”
Does it matter?
Does it matter?
“A bit of warming won’t hurt us” WRONG, WRONG and WRONG! It won’t be “a bit” It’s not the “warmth” – it’s the results of it It will lead to a very different Earth that
hasn’t been seen for millions of years!
Could we be wrong?
Science always has some “uncertainty” It is the nature of science to be “sceptical” But the more we find out, the less the
uncertainty Only a tiny handful of climate scientists are
not convinced Most of those have vested interests (Plimer)
or strong political (Lindzen) or religious (Spencer) views
ALL major scientific academies and institutions around the world have made statements to the effect that climate change is real, human caused, and requires urgent action
• Would you get on this aeroplane if 1 out of 10 engineers found dangerous cracks in the wings?
Uncertainty in Science
• How about if 9 out of 10 engineers said there were dangerous cracks in the wings and 1 said they didn’t matter?
Uncertainty in Science
That’s about the proportion of scientists saying climate change is dangerous!
Actually it is more like over 97%
“This image was digitally altered!”
That’s about the proportion of scientists saying climate change is dangerous!
And if it’s NOT a big hoax?
But why should we do anything while nobody else does?
Many are doing FAR more than us!
Trial and error in a carbon world Adam Morton Sat Age November 12, 2011
News Ltd consistently avoids or distorts climate issues:
Prince Frederik visits wind farm
Media Bias
Media Bias
But no mention of the Vestas connection and the comments about the 2 km policy!
Media Bias
The Coal Seam Gas issue:
Emissions “up to 87% smaller”
Media Bias
The Coal Seam Gas issue:
Emissions “up to 87% smaller”
Media BiasHow to get 87% less!
Media Bias
Radio 2GB anti C tax or anti climate science
(Aug – Nov 2011)
Radio 2GB pro C tax or pro climate science
(Aug – Nov 2011)
Media Bias
Overview
Some old science The big experiment … The Earth’s climate Is the Earth warming? Does it matter?
What can we do about it?
BUT THERE IS GOOD NEWS!
We CAN move to a sustainable future
www.beyondzeroemissions.org