The 19th Century roots of Climate Science

Joseph Fourier and the Greenhouse Effect

Writers and researchers in the second half of the 19^th century credited Fourier with being the first to allude to the greenhouse effect.

In an article in 1924 (and reprinted in English in 1927) he wrote:

the temperature (of the Earth) can be augmented by the interposition of the atmosphere, because heat in the state of light finds less resistance in penetrating the air, than in repassing into the air when converted into non-luminous heat.

Source: Fourier J (1824). "Remarques Générales Sur Les Températures Du Globe Terrestre Et Des Espaces Planétaires". Annales de Chimie et de Physique 27: 136-67, quoted at this link.

The quotation sounds remarkably like the modern understanding of the greenhouse effect, but Fourier's understanding of the phenomenon is often overstated. He seems to mean by the quote something like the operation of greenhouses, which do not work the same way as the modern effect named (erroneously) after them. Fourier also thought that the atmosphere was warmed more effectively by other factors including the internal heat of the planet and heat from the stars.

For a detailed discussion of Fourier and the greenhouse effect see this link, from pages 55 to 64. A brief analysis can be found on pages 2 and 3 of this document.

The Discovery Greenhouse Gasses by John Tyndall

John Tyndall (1820 - 1893) was a very active and prominent 19^th physicist who made many original discoveries but is best remembered for his work on greenhouse gasses. His main experimental work in this field was in 1859. He discovered that the main constituents of the atmosphere, nitrogen and oxygen are transparent to infrared radiation, but that a number of trace gasses in the atmosphere were effective in absorbing infrared radiation. The main ones were water vapour and carbon dioxide (CO₂).

Tyndall's experimental apparatus is shown in the drawing below.

Tyndall was aware of the implications of his finding when he noted:

To the eye, the gas within the tube might be as invisible as the air itself, while to the radiant heat it behaved like a cloud which it was almost impossible to penetrate. Thus, the bold and beautiful speculation has been made an experimental fact. The radiant heat of the sun does certainly, pass through the atmosphere to the Earth with greater facility than the radiant heat of the Earth can escape into space.

A source for the quotation can be found here.

(It is interesting to note that in the chair of Tyndall's demonstration of his discovery was Albert the prince consort. It is a sad reflection on the current political classes that a significant fraction of today's politicians do not take the active interest in science that Prince Albert did. Many of the current crop of politicians and journalists reject and distort the science on political and ideological grounds.)

Like many scientists of his time, Tyndall was particularly interested in explaining changes of climate in the past, as it was becomming increasingly clear that Europe had suffered ice ages in the past.

Tyndall was aware that the growth of industry was putting CO₂ into the atmosphere but it was almost four decades before scientists seriously investigated the effect of increasing CO₂ in the atmosphere.

For more information on Tyndall see this link.

Svante Arrhenius's Greenhouse Calculations

Arrhenius was a Swedish physicist who published a study in 1896 into the effect on climate of changing the amount of CO₂ in the atmosphere. Tyndall had shown that increasing CO₂ would warm the climate and decreasing it would have a cooling effect. The interesting question was by how much would temperature be effected? Arrhenius performed long and tedious pen and paper calculations to provide an answer to this question. He realised that the effect of CO₂ is complicated by feedbacks, what he called "the mutual reaction of the physical conditions". A major feedback process involves water vapour, which is a much more effective greenhouse gas than CO₂. The increase in temperature caused by an increase in CO₂ would result in more water vapour in the atmosphere which would amplfy the warming produced by increasing CO₂.

Arrhenius calculated that doubling the amount of CO₂ in the atmosphere would result in a 4⁰C increase in global temperature. This wasn't a bad result as the currently accepted value is about 3⁰C.

A few years after Arrhenius published his result Ångström published a strong criticism of it. Ångström's basic argument was that the infrared is already saturated and that increasing the CO₂ in the atmosphere would not effect the absorption of the infrared radiation. This argument is still used by climate science deniers today. For an explanation of why this argument by Ångström was incorrect see the posts here and here.

For biographies of Arrhenius see posts here and here.

Review: La La Land

Warning    Spoilers    Ahead

We have been watching some tough, violent, though compelling TV shows including Walking Dead, Peaky Blinders, Vikings, Handmaids Tale, Game of Thrones.

Here is one sample from Walking Dead.



I suggested that some calmer fare was in order so last Saturday we watched La La Land. Although Margaret enjoyed it in the end, she commented part way through that it was fairy floss!

Here is the opening scene, which you might argue supports her contention ...



... though I would argue that it is a positive, vibrant, infectious response to the frustration of a freeway traffic jam.

I expected it to be a good movie, after all, it won 5 Academy Awards, and I wasn't disappointed.

La La Land breathes new life into an old art form that many have thought irrelevant to modern culture.

Mia (Emma Stone) and Sebastian (Ryan Gosling) meet often. The first time was after the traffic jam at the beginning, and that meeting did not go well. She gave him the bird. But they kept "running into each other" and resisted the obvious attraction as can be seen in the "A Lovely Night Scene".



Beautifully acted, lit, filmed, sung and danced!

Eventually they bow to the inevitable and admit their love.

They both have dreams. Mia to be a successful actress, Seb to open a jazz club.

In more conventional musicals they would find a way to stay together and realise their dreams, but not in this story! They have to part to achieve their career desires.

Their final acceptance of their separation is brilliantly displayed at the end of the film. It is five years later. Mia has a successful film career and is married, with children. On a night out with her husband, she enters the Jazz club that Sebastian has opened, and we get an alternative version of the story, as imagined by Mia ...



As the film leaves her reverie and returns to reality Sebastian is playing the piano, but the melody is not resolved, it needs two more notes to reach a cadence. Is this a sign that Sebastian still has hopes for their relationship? The final scene, where they smile at each other from across the room, signals their mutual acceptance of their parting.

The final 9 and a half minutes elevates this movie from a very good one to a great one.

The music finally resolves with the "The End" screen.

Securing your Facebook Account

This post describes the method of securing your Facebook profile.

Facebook on your computer

Open Facebook and go to your Wall / Timeline.

On the right of the menu items, you will find a down arrow. Click on the arrow and a drop-down menu will appear, as can be seen in the graphic below:



Click on Settings (which I have indicated by an arrow).

The menu at left will appear. Click on Privacy which I have indicated with an arrow.

The Privacy Settings and Tools screen will appear as shown below.



The first option is "Who can see your future posts?"

To change this option click on the Edit button that I have indicated with an arrow.



Click on the drop-down box and choose Friends as shown below:



Click on the close button to save this option.

The next option to deal with is "Limit Past Posts". This will hide your past posts on your Wall / Timeline from all but friends.

Click on the "Limit Past Posts" button and the following screen will appear:



The screen below will appear. Click on the "Limit Past Posts" button.



Don't be put off by the warning: "The only way to undo this will be to change the audience of each post one at a time". This is only relevant if you want some of your posts to be public (ie to be seen by anyone). I expect that this will rarely be the case, and if it is only for a small number of posts.

I could extend this post to a tedious length by going through the process of changing the other settings in the detail above. I hope the process is clear.

One important change is to limit "Who can see your friends list?" I chose "Only Me" from the drop-down box in that section. The reason for this is that it is the best security. It completely hides the friends list from non-friends. Friends can see only mutual friends.

You can check how you Wall / Timeline will look to non-friends and friends.

On your Wall / Timeline you will see the option "View Activity Log". Click on the three dots and two options will appear. Click on "View As ..." as shown below:



The screen that will now appear is how your timeline will appear to a non-friend. You can select to see how it will look to a specific friend by clicking on the "View as Specific Person" option near the top of the screen, as shown below, and entering the person's name.


The options that I recommend are:

Who can see future posts	Friends
Limit the audience for posts you've shared ...	Limit Past Posts
Who can send you friend requests	Friends of Friends
Who can see your friends list	Only Me
Who can look you up using your email address	Friends
Who can look you up using the phone number you proveded	Friends
Do you want search engines outside Facebook to link to your profile	No

Some people will think these options are unduly restrictive. Your preferences will depend on your reasons for having a Facebook account. One of these options is very important though: limiting your friends list is important as it protects your friends from unwanted communications.

Facebook on tablets and phones

The processes are similar to those described above, but the privacy settings are accessed from different places in different versions of the Facebook App. The link will called either "Privacy Settings" of "Privacy Shortcuts". They can be found in the left menu if your version has that feature, which is where it is in my iPad. On my iPhone it is in the More menu which is a circle with three dots inside it.

Euler's Identity

Leonard Euler discovered one of the most stunning and beautiful equations in all of mathematics. It is called the Euler Identity. Here is is:



According to mathematician Keith Devlin: "Like a Shakespearean sonnet that captures the very essence of love, or a painting that brings out the beauty of the human form that is far more than just skin deep, Euler's equation reaches down into the very depths of existence"

The first step in understanding how the identity is derived is to study Maclauren and Taylor Series, as described in the following video.


The next step is to develop the Maclauren series for Cosine, as shown in the next video ...


... then the Maclauren series for Sine ...


The next step is to produce the series for e to the x ...


Now we can derive Euler's Identity ...



Additional explanatory videos.

The videos above assume some prior maths knowledge. Here are some videos and links filling in some of the assumed knowledge.

Calculus - is a very large of maths.

Here is a playlist of videos introducing calculus.

The playlist contains a large number of videos, and the derivation of Euler's Identity as described in the videos above only emphasised derivatives so here is a link to some videos on derivatives

Trigonometry

The videos above used sine and cosine extensively, as well as pi. click on this linkfor a playlist on trigonometry which explains these functions.

e the exponential

The base of the Euler's Identity is e. In the last video Sal said that it comes from compound interest. Here are two videos that explain compound interest and how e emerges from it. Video one , Video two .

The Big Bang ... Star Dust ... and the Pale Blue Dot

Introduction

This is a talk that I recently gave to my Probus Club.

On a warm evening in early 1987, I drove out of Melbourne into the countryside with my teenage daughter. We wanted to get away from the bright lights of the city so that we could see the stars clearly.

This was the sight that greeted us.



The majestic band of the Milky Way was the most prominent feature, but we were really there to those two hazy patches to its right.

They are the Clouds of Magellan. Although they were well known to people living in the Southern Hemisphere, Europeans were not aware of them until the late 1400s and early 1500s. They are named after the Portuguese explorer Ferdinand Magellan.

What we were specifically looking for is shown in the next picture. It was the first supernova that could be seen without a telescope for over 300 years. I will explain what a supernova is later. The supernova is the star at the end of the arrow. A month or so before we saw it that star was only visible is very powerful telescopes, and a few months after our country trip it was again invisible to the naked eye.



There were plenty of other astronomical objects to view including this one.



The Southern Cross, the icon of our hemisphere.

The Big Bang ...

The star I particularly pointed out to my daughter is the one at the bottom left. It is called Alpha Centauri. I commented that it is the closest star to us (other than the Sun) and that the light left it four years ago. She expressed surprise, and asked how we know that.

(Note for pedants. Proxima Centauri is actually the closest, but it cannot be seen without a telescope!)

I am not sure that my explanation was clear to her. I will try to make it clear now.

I gave the talk in our regular meeting room, which has a great view out onto Port Philip bay. I turned to the Bay and continued with my talk.

Imagine we can see a ship anchored out in the bay. We might ask ourselves how far the ship is away. Luckily we have a surveyor with us. He takes a sight on the bow of the ship measures an angle of 90 degrees away from the ship and starts measuring our a distance in that direction, call that distance the baseline. After a few hundred metres has been measured the surveyor takes another angular measurement.

The surveyor draws a diagram like the one below. Distance equals baseline multiplied by tan of the angle.

He then writes ... Distance = baseline X tan(angle). ... into his notebook, does a calculation and reports the distance to the boat. This is not difficult maths, as it taught in Secondary School maths classes. If you are interested in investigating this problem further here is a link.

We can use this same method to measure the distance to stars. We need a much larger baseline though. You might think that the diameter of the planet, 12,756 kms, would be enough ...



... but it is too small.

The largest baseline available to us is the radius of the Earth’s orbit around the sun ...



... 300 million kms.

Take pictures of the sky six months apart. When you compare the photos most of the stars will be in exactly the same position – because they are sooo far away. But some close start will be in slightly different positions. We can measure the change in positions of these stars and make a triangle like the one above. So we can determine the distance to some of the stars in the sky.



Using this method the distance to the nearest star – Alpha Centauri – is 41,320,000,000,000 kms. Obviously a km is not a useful measuring unit at these distances. One unit of distance that astronomers use is the Light Year. That is the distance that light travels in one year, which is 9.461 trillion kms. Divide the distance to Alpha Centauri in kms by the number of kms in a light year and you get the distance to Alpha Centauri as 4.36 light years.

So, we can measure the distances to the closest stars, what about the others. Imagine you are near a road at night. You want to cross the road. There is a car coming. On the whole car headlights are a similar brightness. So using the brightness of the car’s headlights we can get an idea how far away it is and whether it is close to cross.



A similar method is used to determine the how far away very distant stars are. If we know a star's intrinsic brightness - how bright it actually is - we can work out its distance away from us by comparing its intrinsic brightness to its apparent brightness, as seen from Earth.

The pioneer in this work was a woman - Henrietta Leavitt. She worked in an era when women were not as valued as they are now, and was not acknowledged publicly for her great contribution. For more details on Leavitt follow this link . Leavitt studied variable stars called Cepheid Variables.

The calculation at left shows how to determine the distance to a star if its intrinsic brightness (L) is known and its brightness as seen from Earth (F) is measured. Light leaves a star in all directions, which means that it expands in a spherical shell. The surface area of a sphere is where r is the radius of the sphere. The amount of light reaching us from a star is the star's intrinsic brightness (L) divided by the area of a spherical surface with a radius the distance that the star is away from us - the first equation at the left. Here is a link to a video that further explains the derivation of the equation.

 All we need to do is solve for r, which is the distance that the star is away from us. The final equation gives the answer - the distance to the star is the square root of the intrinsic brightness of the star divided by 4 times pi times the measured brightness.
For more information on these methods of measuring astronimical distances click on this link .

Using Cepheid's and other astronomical objects as described in the link above we can determine the structure of our local group of stars, the Milky Way Galaxy, as shown in the graphic below. Note that our solar system is just over half way out from the centre.



Here is what out galaxy would look like if we could view it from outside.



There are many hazy smudges (like the Magellanic Clouds) in the night sky and before methods to measure distances to stars were developed there were two points of view about them. Some astronomers thought the fuzzy patches were part of our local group of stars (the Milky Way) others thought that they were external to our galaxy. Powerful new telescopes that were developed in the early 20th Century resolved stars in these fuzzy patches. Cepheid Variable stars were found in them and their distances determined. These fuzzy patches were found to be outside our galaxy and often an enormous distance away.

The distance to the Large Magellanic Cloud was determined at about 158,000 light years.

The nearest large galaxy to our own is in the constellation Andromeda, and is about 2.5 million light years away.



So we can calculate the distances to other galaxies.

The next question is how are they moving?

I will start with a familiar issue, determining the velocity of a moving sound source.

Sound is waves in the air. When a sound source is moving towards you the sound waves are compressed and the pitch of the sound is increased. When a sound source is moving away from you the sound waves are stretched and the sound has a lower pitch.

In the diagram below the police car siren sounds a higher pitch as it approaches. When it is level with the listener the sound pitch drops to the actual siren pitch and then lowers in pitch as it moves away.



So we know the speed of sound, the pitch of the source and the pitch as it approaches and recedes.

It is possible to calculate the speed of the sound source (in this example the police car) using that information. There is a formula for this. A formula for an approaching vehicle is:



Where V_s is the speed of the source, C is the speed of sound, f_o is the (stationary ) frequency of the source and f is the measured frequency.

There is also a (slightly different) formula for a receding source.

Light is also a wave and it is possible to measure the speed of objects using changes in their light frequency. Red light is long frequency and blue light is short frequency. Yellow, orange and green are in between frequencies, as can be seen in the diagram below.



When an object is moving towards you the light frequency will compress and the light will shift in the blue direction (blue shifted). If a light source is receding then the light waves will be stretch and the light will be shifted in the red direction (red shifted).

A similar method to that used to determine the speed of a sound source can also be used to measure the speed of a light source, as described in the video below.

So it is possible to measure the distance to galaxies and the speed that the galaxies are moving. The photograph shows Hubble Hubble observing at 100 inch Mt Wilson Telescope.

You might expect that about half of the galaxies would be moving towards us and about half moving away from us. But this is not Edwin Hubble found when he studied many galaxies in the 1920s. In 1927 he announced that virtually all galaxies are moving away from us and the further away a galaxy is the faster it is moving away, as shown in his plot, below.



The universe is expanding!

Two explanations for this phenomenon were developed.

The Big Bang – the most obvious explanation of the expanding universe is that we are living in the aftermath of a massive explosion. This was one of the explanations developed. It was called the Big Bang by Fred Hoyle, one of the theory’s opponents.

The Steady State – that the universe has always been expanding and that new matter comes into existence in the gaps left by the galaxies as they move apart, and over time new galaxies form.

There was for some time no evidence to distinguish between these two explanations until two guys came along in the mid-1960s who were working on a completely different problem. Satellites were a new phenomenon and Penzias and Wilson built a horn antenna in an attempt to improve satellite communication. The photograph below whows Penzias (on the right) and Wilson (on the left) with their antenna in the background.



They had a problem though. There was a distracting hiss in their instrument. They thoroughly checked the instrumentation, but could not find the source of the hiss. The news got around of their problems and they received a phone call from Robert Dicke that their discovery was a firm prediction of the Big Bang theory. It was nothing less than the afterglow of the Big Bang. This observation did not fit comfortably into Steady State cosmology. Relatively quickly most astronomers moved into the Big Bang camp.

When did the Big Bang occur? There are a number of different methods of determining this. The easiest to understand is to measure the expansion rate and then work that backwards to determine how long ago all matter in the universe was in one place.

The currently accepted age of the universe is 3.8 billion years ie 3,800,000,000 years. The short video below explains how this age is calculated.

... Star Dust ...

What did the Big Bang produce. You might expect that all of the elements that currently exist came out of the Big Bang, but that is not true. The Big Bang produced only hydrogen, helium and a little bit of lithium.

Only 9.5% of the elements that we are made from came out of the Big Bang. Where did all of the other elements that we are made of come?



The answer is stars – we are literally stardust!

Our planet is warmed and lit by light coming from the sun. Where does that energy come from. The answer is surprising. In its core the sun is millions of degrees hot, and hydrogen is being converted to helium, a process that produces energy.

The graphic below shows one of the process by which hydrogen nuclei produce helium.



The sun is a medium sized star, but in larger stars many more elements are produced, as shown by the graphic below. For a video describing the details on how this process occurs click on this link .



Evenutally the core of the star rapidly fills up with iron. This is a crisis for the star, as synthesising more elements from iron does not release energy, it requires more energy. So energy production suddenly stops in the star. The star has existed by two forces balancing each other - gravity trying to crush it and the energy produced in the core trying to push it apart.

Without energy coming from the core gravity wins and the star collapses. This collapse produces a great deal of energy which then blows the star apart, spreading all of the elements that have been formed out into the universe. This explosion also provides energy for the production of elements heavier than iron.

Some of these elements ended up in vast cosmic clouds - that consisted mainly of hydrogen - like the one in the photo below.



Four and a half billion years ago a cloud like that collapsed to form the Solar System. (Note the photo below is not to scale.)



The third planet from the sun is very unusual, as life has developed on it. There is clear evidence for life 3.6 billion years ago, and it is likely that life started earlier than that.

Here is a link to a video describing the latest ideas on how life formed on Earth.

There is no time here to consider the processes of how life evolved and diversified over billions of years, though if you are interested in this click on this link for a brief 36 minute exposision. Instead we will jump forward to just 260,000 years ago when a new creature arose on the plains of Africa. There was intelligence behind those eyes that looked up at the stars and made stories about them. Or species eventually explored the whole of the planet and then looked around for a new exploration challenge. What about that large ball in the night sky!

... and the Pale Blue Dot

So we return to the 1960 and the Apollo Space program. The first crewed Apollo craft to orbit the moon was Apollo 8. The graphic below shows its flight path.



One of the major tasks of Apollo 8 was to survey possible landing sites for the later missions, but it is most remembered for an event that took place during its fourth orbit. One of the Astronauts, Bill Anders said, "Oh. Look at that picture over there. There's the Earth comming up. Wow, that's pretty. Anders took a series of photos, one of which became one of the most celebrated photos ever taken - Earthrise.



The taking of the photo was without doubt one of the most profound events in the history of human culture, for at this moment we truly saw ourselves from a distance for the first time; and the Earth in its surrounding dark emptiness not only seemed infinitely beautiful, it seemed infinitely fragile. This wonderful image crystallised and cemented the sense of the planet's vulnerability.

Click on this link for a video that describes Apollo 8 and the taking of the Earthrise photo.

Eight years after Neil Armstrongs "... small step ..." in 1977, Nasa launched two space craft Voyager 1 and Voyager 2, to explore the outer planets.

Click on this link for a video describing the history, achievements and future of the Voyager space probes.

They gave us photographs of unprecedented detail of:

the majestic Jupiter



Saturn, with its beautiful rings



Uranus



and Neptune



Voyager 1 only visited Jupiter and Saturn, but Voyager 2 visited all four outer planets. When Voyager 1 had completed its mission Carl Sagan, an astrophysicist, writer and consultant to NASA, suggested that the space craft be turned around and take a picture of all of the planets including Earth. The photo of earth, shown below, was called the Pale Blue Dot.



In the photograph, the arrow points the the Earth, which appears as a pale blue dot.

I could describe this photograph, but instead I will leave that task to a much better wordsmith than me, Carl Sagan. To hear Sagan's wonderful, and uplifting description listen to the video below.

Expert Opinion on Climate Change

I wrote most of this post in 2011, with an update in 2013.

There is little need for an update now as all of the organisations discussed have maintained their acceptance of mainstream climate science.

The main change since the original posting is the Paris Climate Agreement of December 2015. All world governments have signed the agreement, though the Trump Administration in the US has signalled a desire to leave. That can't happen till 2020. So all of the World's governments, with the exception of the US accept mainstream climate science!

I regularly receive emails attacking basic Climate Science. Such attacks also appear frequently in some media publications.

It is possible to spend a great deal of time checking these claims, but this is not a viable option for most people.

A quicker method is to check the opinions of acknowledged experts, which would include our premier science organisations.

This post looks at the views of eight major science organisations and demonstrates that they all support the view that humans are warming the planet dangerously. It finishes with link to fifty more science organisations with similar views.

The UK MET Office

This post will reference many documents, which would require a great deal of time to fully read so I will start with a brief video from the UK MET Office:



The UK MET Office view is clear:

The current changes are very unusual and can not be explained simply as part of any natural cycle, such as El Nino and La Nina, which cause the warming and cooling of the tropical Pacific Ocean, which affects world temperature. Natural cycles can lead to periods with little or no warming and other periods with rapid warming. However, what is important is looking at the longer term trends in temperature,which are rising, and which scientists believe is almost certainly caused by human activity.

When studying climate change, scientists draw their evicence from many sources. Are humans contributing to the warming we are observing? Or could it be natural causes and changes to theclimate? Scientists, such as those at the Met Office Hadley Centre, are continuing to look at all the possible effects, both man-made and natural. However, it is widely understood that our emissions of greenhouse gases are causing changes to our climate.

At the MET Office FAQ site the following is given in answer to the question: "Can anything be done about Climate Change?"

On present evidence, global warming could be slowed if emissions of methane and carbon dioxide were reduced. The main artificial sources of these gases are (a) for methane - agriculture, emissions from landfill sites and natural gas and (b) for carbon dioxide - the burning of fossil fuels, cutting down and burning trees. This may seem to be something that only governments or large organisations can tackle, but the individual can also contribute significantly by, for example, not using a car unnecessarily and recycling.

For more information about the MET Office's view of Climate Change follow this link.

The Australian Academy of Science

The Australian academy of Science is Australia's foremost science organisation. In 2010 it released a report on climate science. The report can be found here.

The report begins with the following paragraph:

The Earth's climate has changed. The global average surface temperature has increased over the last century and many other associated changes have been observed. The available evidence implies that greenhouse gas emissions from human activities are the main cause. It is expected that if greenhouse gas emissions continue at business-as-usual rates, global temperatures will further increase significantly over the coming century and beyond.

The rest of the 24 page report provides the evidence to substantiate the claims in the first paragraph.

The CSIRO

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is Australia's premier science research organisation.

In 2011 CSIRO published a booklet called Climate Change: Science and Solutions for Australia. The document can be downloaded here.

The opening paragraph of the document states:

Climate change is one of the greatest ecological, economic, and social challenges facing us today.The scientific evidence that human activities are contributing to climate change is compelling, but society is increasingly seeking information about the nature of the evidence and what can be done in response to a changing climate. This book provides some of that much-needed information from some of Australia’s leading climate scientists.

Chapter 2 notes the following Key Messages

• Greenhouse gases (GHGs) influence the Earth’s climate because they interact with flows of heat energy in the atmosphere.

• The main GHGs influenced directly by human activities are carbon dioxide (CO2), methane, nitrous oxide,ozone, and synthetic gases. Water vapour, although an important GHG, is not influenced directly byhuman activities.

• The amount of warming produced by a given rise in GHG concentrations depends on ‘feedback’ processes in the climate system, which can either amplify or dampen a change. The net effect of all climate feedbacks is to amplify the warming caused by increasing CO2 and other GHGs of human origin.

• The atmospheric level of CO2 (the most important GHG influenced by human activities) rose from about280 ppm in 1800 to 386 ppm in 2009, and is currently increasing at nearly 2 ppm per year.

• CO2 levels are rising mainly because of the burning of fossil fuels and deforestation. Over half of thisCO2 input to the atmosphere is offset by natural CO2 ‘sinks’ in the land and oceans, which constitute a massive natural ecosystem service helping to mitigate humanity’s emissions.

• To have a 50:50 chance of keeping human-induced average global warming below 2ºC, it will be necessary to stop almost all CO2 emissions before cumulative emissions reach one trillion tonnes of carbon. The world has already emitted more than half of this quota since the industrial revolution, and (at current growth rates for CO2 emissions) the rest will be emitted by the middle of this century.

• Climate change is a risk management issue – the longer we take to act and the weaker our actions, the greater the risk of dangerous outcomes.

The Australian Bureau of Meteorology

The Australian Bureau of Meteorology has produced a document called State of the Climate 2010

The report can be found here.

The report concludes with the following observations:

Australia will be hotter in coming decades

Australian average temperatures are projected to rise by 0.6 to 1.5 ºC by 2030. If global greenhouse gas emissions continue to grow at rates consistent with past trends, warming is projected to be in the range of 2.2 to

5.0 ºC by 2070. Warming is projected to be lower near the coast and in Tasmania and higher in central and north-western Australia. These changes will be felt through an increase in the number of hot days.

Much of Australia will be drier in coming decades

In Australia compared to the period 1981-2000, decreases in rainfall are likely in the decades to come in southern areas of Australia during winter, in southern and eastern areas during spring, and in south-west Western Australia during autumn. An increase in the number of dry days is expected across the country, but it is likely that there will be an increase in intense rainfall events in many areas.

It is very likely that human activities have caused most of the global warming observed since 1950

There is greater than 90% certainty that increases in greenhouse gas emissions have caused most of the global warming since the mid-20th century. International research shows that it is extremely unlikely that the observed warming could be explained by natural causes alone. Evidence of human influence has been detected in ocean warming, sea-level rise, continental-average temperatures, temperature extremes and wind patterns. CSIRO research has shown that higher greenhouse gas levels are likely to have caused about half of the winter rainfall reduction in south-west Western Australia.

Climate change is real

Our observations clearly demonstrate that climate change is real. CSIRO and the Bureau of Meteorology will continue to provide observations and research so that Australia’s responses are underpinned by science of the highest quality.

UPDATE: The 2012 State of the Climate Report has been released and can be found at this link.


US Academy of Science

The US Academy of Science (the peak Science body of the US) has also produced a report on climate science which can be accessed here.

The first conclusion of the report (found on page 3) is:

Climate change is occurring, is caused largely by human activities, and poses significant risks for—and in many cases is already affecting—a broad range of human and natural systems

That conclusion is supported by the following dot points:

• Earth is warming. Detailed observations of surface temperature assembled
  and analyzed by several different research groups show that the planet’s average surface temperature was 1.4ºF (0.8ºC) warmer during the first decade of the 21st century than during the first decade of the 20th century, with the most pronounced warming over the past three decades. These data are corroborated by a variety of independent observations that indicate warming in other parts of the Earth system, including the cryosphere (snow- and ice covered regions), the lower atmosphere, and the oceans.

• Most of the warming over the last several decades can be attributed to human activities that release carbon dioxide (CO2) and other heat-trapping greenhouse gases (GHGs) into the atmosphere. The burning of fossil fuels—coal, oil, and natural gas—for energy is the single largest human driver of climate change, but agriculture, forest clearing, and certain industrial activities also make significant contributions.

• Natural climate variability leads to year-to-year and decade-to-decade fluctuations in temperature and other climate variables, as well as substantial regional differences, but cannot explain or offset the long-term warming trend.

• Global warming is closely associated with a broad spectrum of other changes, such as increases in the frequency of intense rainfall, decreases in Northern Hemisphere snow cover and Arctic sea ice, warmer and more frequent hot days and nights, rising sea levels, and widespread ocean acidification.

Joint Academies Statement

Thirteen Academies of Science have regularly made a statement on climate change. The academies are those of: the US, UK. France, Germany, Japan, Canada, Italy, China, India, Brazil, Mexico, Russia and South Africa, the G8 plus 5 group.

In their most recent statement (found here) they give the following recommendations:

Recognizing the vital role that low carbon energy systems must play in facilitating a sustainable global economy, the G8+5 nations need to seize all
opportunities to coordinate our simultaneous work on the climate and economic agendas, and to build global collaboration.

We call on all governments to:

• agree at the UNFCCC negotiations in Copenhagen to adopt a long-term global goal and near-term emission reduction targets that will deliver an approximately 50% reduction in global emissions from 1990 levels by 2050;

• significantly increase fundamental international research on the earth’s climate, on low carbon and climate resilient technologies, and on ways to protect and enhance the resilience of natural systems to climate change;

• identify the common strategic priorities for developing and implementing environmentally sustainable technologies for adaptation and mitigation;

• collaborate in the implementation of low carbon and climate-resilient infrastructure and technologies, and in the implementation of innovative incentives,
  through the use of economic and regulatory instruments, to accelerate adoption of clean “green” technologies;

• support and enable developing countries’ access to and use of the technologies needed to deliver a sustainable low carbon energy future;

• pursue the development, demonstration and deployment of economically efficient and technologically safe CCS, and explore the establishment of standards for CCS;

• pursue international cooperation on safe and secure nuclear power capacity, the safe disposal of nuclear waste, and the reduction of the risk of proliferation;

• substantially increase investment into the development and deployment of technologies for adaptation, and increase funding specifically for the most vulnerable countries.

Education and public awareness programmes will be essential as we pursue this agenda. We must build on the current enthusiasm and engagement of a younger generation.

The US National Oceanic and Atmospheric Administration (NOAA)

NOAA is one of the major oceanic and atmospheric research and reporting organisations. Each year NOAA produces a document called State of the Climate. The full report for 2010 can be downloaded here and the summary here.

Page 6 of the summary:

The World Continues to Warm

• Multiple indicators, same bottom line conclusion

Consistent and unmistakable signal from the top of the atmosphere to the bottom of the oceans

The conclusion makes the following points:

• 2010 global average surface temperature among the two warmest on record

• 2010 report tracks 41 climate indicators. Long-term trends continue to show the world is warming

The Royal Society

The Royal Society is the most prestigious science organisation in the world. It is Britain's National Academy of Science.

The Royal Society produced a document on Climate Science in 2010, which can be downloaded here.

The report begins as follows:

Changes in climate have significant implications for present lives, for future generations and for ecosystems on which humanity depends. Consequently, climate change has been and continues to be the subject of intensive scientific research and public debate.

There is strong evidence that the warming of the Earth over the last half-century has

been caused largely by human activity, such as the burning of fossil fuels and changes in land use, including agriculture and deforestation. The size of future temperature increases and other aspects of climate change, especially at the regional scale, are still subject to uncertainty. Nevertheless, the risks associated with some of these changes are substantial. It is important that decision makers have access to climate science of the highest quality, and can take account of its findings in formulating appropriate responses.

I could keep discussing the views of more science organisations, but this post is already quite long.

UPDATE

The World Bank

In November 2012 the World Bank released a report titled: "Turn Down the Heat: &nbsp &nbsp Why a 4⁰ Warmer World Must Be Avoided. Here is a link to the document.

The first paragraph of the Executive Summary sets the tone of the whole document.

Without further commitments and action to reduce greenhouse gas emissions, the world is likely to warm by more than 3°C above the preindustrial climate. Even with the current mitigation commitments and pledges fully implemented, there is roughly a 20 percent likelihood of exceeding 4°C by 2100. If they are not met, a warming of 4°C could occur as early as the 2060s. Such a warming level and associated sea-level rise of 0.5 to 1 meter, or more, by 2100 would not be the end point: a further warming to levels over 6°C, with several meters of sea-level rise, would likely occur over the following centuries.


PricewaterhouseCoopers

PricewaterhouseCoopers trades as PwC. In November 2012 it released a report called: "Too late for two degrees? Low carbon economy index 2012". The report can be downloaded from this link. Discussion of this report can be found in this page of the PwC website.

The video below is from the PwC website linked to above. It makes a number of important points: 1. The longer we wait to get serious about emissions reduction the harder the task will become, 2. To refuse to reduce emissions is extremely dangerous, and, 3. Countries that develop the new technologies to meet the challenge will have an important new source of wealth.



To quote from page 2 the report:

The PwC Low Carbon Economy Index evaluates the rate of decarbonisation of the global economy that is needed to limit warming to 2°C. This is based on a carbon budget that would stabilise atmospheric carbon dioxide concentrations at 450 ppm and give a 50% probability of limiting warming to 2°C.

This report shows that global carbon intensity decreased between 2000 and 2011 by around 0.8% a year. In 2011, carbon intensity decreased by just 0.7%. The global economy now needs to cut carbon intensity by 5.1% every year from now to 2050 to achieve this carbon budget. This required rate of decarbonisation has not been seen even in a single year since the mid-20th century when these records began. Keeping to the 2°C carbon budget will require unprecedented and sustained reductions over four decades.

Governments’ ambitions to limit warming to 2°

For information on another fifty science organisations that support the climate consensus position follow this link.

List of articles on Climate Science http://www.davidappell.com/EarlyClimateScience.html

Climate Science

Introduction

Climate science has a long history.

1. Fourrier
In the 1820s Joseph Fourier published realised that the atmosphere warmed the surface of the planet, although he did not have a clear idea of the reason.

2. Thirty years after Fourier's work, John Tyndall carried out experiments that supplied a mechanism for Fourier's observation - Greenhouse Gasses