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I expect over time to add pieces, make changes and correct errors.
Before we go further, I have to explain why there is no "comment" option any longer. One word. Spam. As on most sites with an open facility, we seem to have attracted rather a lot of these odd folk and have, sadly, had to make this change to protect our sanity.
I must say to the spammers, though, that we appear to have attracted a better class! None of your cheap erection corrections or porn. No, we get people marketing cheap handbags and shoes using such proud names as Louis Vuitton, Chanel, Gucci, Christian Louboutin and Prada! Occasionally someone offered a comment about compatibility but then ruined their discourse by layering in links to these cut-price clothing brands.
I have now linked this site to my Facebook page, so maybe you can leave comments there if you wish. But please keep it civil, stick to facts, correct my errors. Most of all, let's have an open discussion.
Now on to the point of this blog.
Am I a climate change “believer” or “sceptic”?
Perhaps the question should more accurately be framed as a discussion of whether the data we are asked to absorb and the various positions put to us are accurate and the conclusions reasonable.
Discussions about climate and climate change should be about science. So being a believer or a sceptic seems absurd. It is as if we are being asked whether we “believe” in science. Belief has nothing to do with it. Science involves crafts, skills and knowledge. Do I believe in a carpenter?
Perhaps I should state my thoughts on the subject at the outset because it may have skewed the discussion below and readers ought to be aware of that potential. I have tried not to skew, but we all carry our prejudices into any discussion.
First, I was motivated to set down my thoughts by the increasingly vitriolic nature of the debate. I am offended by people who attack others when the discussion should be about the science, not about people. Note, I have not used the word “fact”. Science is not necessarily “fact”. More often than not, it is theory, postulation, methods of proof. My father was a scientist, so I know something of that profession. One of the oddities of scientists is that it is difficult to get them to commit to a position. They always qualify what they say. Einstein did not, for example, hand down the laws of relativity. He offered a theory. Darwin offered a theory about evolution.
When we read or hear that scientists on any side of the debate receive death threats – or any kind of threat - it hurts the chances that good sense will prevail. It was only a few hundred years ago that some scientists were jailed – or worse – for discussing certain propositions. The famed astronomer and mathematician Galileo was thrown into house arrest in 1633 after he published a book promoting the idea of heliocentrism – that the Earth and other planets rotate around the Sun. Charles Darwin delayed the publication of his seminal work “On the origin of species” for fear of a church-led backlash. He formed his theory in 1838 but the book was only released 21 years later. The backlash occurred nevertheless.
Let us leave the scientists to provide information and analysis and interpretation and assume they all mean well. We can also assume they will not all agree. But it helps if we respect their endeavours.
Second, I carry a general belief about positions in a debate in which there is no absolute proof. Let me use an analogy. I go to my general practitioner for a check-up for no other reason that one should do so on occasion, just to make sure all is working as it should. My doctor does all the normal tests, sends samples off to laboratories and then calls me to say there appears to be something wrong. Not life threatening, but worth checking. I go to another doctor who generally agrees and tells me I should consider some lifestyle changes. Nothing drastic. But I will need to cut out some of the foods I really like and buy some medication. If I choose to do nothing, the opinion of both doctors is that my condition will probably get worse and the cost of remedy will be higher.
Not fully satisfied with this generalist result, I consult another doctor, and then another. I find one who looks at the same test results that the others have seen and he says they are wrong and there is absolutely nothing to worry about. It’s just a stage of life. After a bit more doctor shopping I find myself with the following general position. I have eight who tell me there is something wrong, that changes in lifestyle are needed. I’m not going to die but, if I don’t make a few adjustments now, it will simply get worse and then I might not like the changes I would need to make. It could get expensive. Two doctors, on the other hand, tell me I need to do nothing. What do I do?
My tendency is to go with the weight of scientific evidence, countered by a curious mind and a knowledge that scientists have been proven wrong by time and increasing understanding. Science is in a constant state of flux, as is just about everything on our planet.
So the discussion below is an attempt to draw together some of the arguments, counter-positions and to dispassionately set down what I have learned.
What follows is the result of my reading and listening and a bit of viewing. Mainly reading.
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Our understanding of the world changes and develops all the time. Until relatively recent times in human history, the vast majority of people believed that the world was flat and that the Sun, Moon and stars oscillated above us. Basic individual observation even today would suggest that might be the case. We can’t easily see the curvature of the Earth. A couple of the ancient Greeks theorised that the world might not be flat but their theories did not last. Even as late as 1600 the idea that Earth was not the centre of the universe was controversial. Galileo’s fate is mentioned above. By the way, his predecessor, Copernicus, was first to publish a book theorising that the Sun was the centre of the Universe and not Earth. His book was initially accepted even by the church. Fortunately for him perhaps, he died before the priests decided such ideas were against holy scripture and set out to “correct” his work.
Today, it is generally accepted in scientific circles and in much of the wider community that, not only do the Earth and other planets in our solar system rotate around the Sun, our solar system is a small part of a massive galaxy which is just one of many galaxies across the universe. No doubt our understanding will expand even further over time. That is the nature of science. So let us not suggest putting scientists under house arrest or worse!
Any discussion of climate change must surely be undertaken in an environment of general acceptance of the advancement of science. Those who hold to the Biblical view would, I assume, also hold that the world climate is controlled by God. After all, he created it in seven days and He is not about to let humans mess it up. And let us not think he built it and then stood back and let man/woman go to it. His interventionism is demonstrated in the first Book of the Bible, Genesis. First He cast Adam and Eve out of the Garden of Eden for disobeying an instruction. Then He cast out Cain for knocking off his brother. After watching many generations grow and develop, God became so frustrated by the “wickedness” of man that he decided to wipe all living things off the face of the Earth and start again with one carefully selected family – Noah, his wife and children and their wives. And all the animals and plants they would carry in the Ark. If He wants to, it seems, God has no issue with intervention.
Certainly there are a few scientists who hold to a Creationist belief. I prefer my scientists to be agnostic on most things: seeking proof – without prejudice. If one holds that Darwinian evolution is the ONLY possibility, then all subsequent work is likely to be bent toward supporting that held belief. Equally so with Creationism or any other entrenched belief.
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I have a feeling that much of the struggle we have with the discussion about climate change is in the difference between weather and climate.
So let’s have a go at clarifying. Weather is what happens every day, the fluctuations in temperature, cloud cover, rain or sunshine. Billy Connolly made a wonderful comment about weather on one of his “World Tour” documentaries: “There is neither good nor bad weather, but our attitude towards it”.
Climate is what happens in a region or across the planet over a long period of time – years.
Our general focus is on weather. What will I wear tomorrow based upon what the weather man predicted on the TV? How accurate can I expect that prediction to be? These days, quite accurate. On the other hand, what do I expect the weather to be like in six months when I want to take a holiday? Should I go to Cairns or Jindabyne in August? That depends on whether you enjoy swimming or snow skiing. The former decision is based on weather, the latter on climate.
It seems that we are being told that, unless we take drastic action to reduce the amount of carbon dioxide – and other “greenhouse” gases - we are pumping into the atmosphere, temperatures will rise by at least two degrees Celsius! For us mere mortals, the idea of an increase of two or even four degrees is nothing to get excited about. We see fluctuations in temperature of 10 degrees in a single day and similar fluctuation even between daily maximums every year. So what is the problem? People in Tasmania might welcome the average increasing by two or even four degrees.
Equally, the predictions of sea level rise are hard to fathom. Each day we see the tide rise and fall and it can vary between about a metre and five or six metres. So why should anyone fuss about a rise of a metre or two. If you live on Tuvalu, a nation of reef islands and atolls in the southern Pacific, it is probably vitally important.
The numbers are so strange that they are difficult to grasp and scientists are generally abysmally poor at explaining what they mean. So we have a debate between eminent people taking opposing sides and we can barely relate to any of it - except to be afraid of some of the more extreme predictions. Movies such as The Day After Tomorrow, in which climate change is seen wreaking havoc on an unsuspecting populace, play on our fears. Equally, when the logical side of our brain fathoms that these dire predictions are the stuff of Hollywood, we tend to reject the entire proposition as false.
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The debate about climate change has been going on for a long time – more than 100 years.
French physicist Joseph Fourier was the first to document the greenhouse effect. Fourier suggested in 1824 that the Earth stays warm at night because its atmosphere traps sun-warmed gases in the same way that a greenhouse holds heated air - hence “greenhouse gases”.
In 1896, Swedish physical chemist Svante Arrhenius predicted that, if levels of carbon dioxide in the atmosphere doubled, the average temperature of the Earth would rise between 1.6 and 2.1 degrees Celsius. Arrhenius was later involved in setting up the Nobel Institutes and the Nobel Prizes.
But not every scientist agrees that the world is undergoing anthropogenic (man-made) warming. In fact, in the 1970s, climate scientists debated whether the globe might be warming or cooling. They were not sure.
Time magazine for June 24, 1974 declared: "However widely the weather varies from place to place and time to time, when meteorologists take an average of temperatures around the globe they find that the atmosphere has been growing gradually cooler for the past three decades."
The debate moved into the public domain at about the time of the Kyoto Protocol on climate change in 1997.
But why the focus on carbon dioxide? After all, it forms such a tiny percentage of Earth’s atmosphere. In fact, the Kyoto Protocol covers four greenhouse gases: carbon dioxide, methane, nitrous oxide and sulphur hexafluoride.
The Earth’s atmosphere is made up of about 78 percent nitrogen, 20 percent oxygen and 0.9 percent argon. That leaves 1.1 percent for everything else. In fact, the consensus is that, at the beginning of the 20th century, carbon dioxide accounted for about 280 parts per million in the atmosphere. That was 0.028 percent of the atmosphere!
How could a gas which takes up just 0.028 percent of our atmosphere cause our climate to warm?
On its own, it doesn’t, of course. There are the other greenhouse gases mentioned above and even water vapour. All make up tiny percentages of the atmosphere. Yet we should be grateful for them. Without them, Earth would be a frozen wilderness (first proposed by Joseph Fourier - see above). Scientists can calculate the amount of heat that reaches planet Earth from the Sun. It is not a lot; not enough to sustain life as we know it. So the greenhouse gases help to capture the heat radiated by the Sun and hold it in the troposphere, the layer of the atmosphere closest to the surface of Earth. Those gases might be poorly represented in the atmosphere, but they pack a punch.
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Climate scientists are a broadly based bunch including meteorologists, oceanographers, ecologists, geologists, biologists, physicists and a variety of other specialties. Equally we have a range of zoologists and botanists weighing into the discussion with their observations about changes in their branch of ecology. And economists enter the debate with their discussions of economic impacts of change, action, inaction and cost.
Scientists at every level conduct their work and careers under close scrutiny in an environment that is known as peer review. For a scientific discovery or proposition to be accepted, the work generally follows a particular process. First, a paper describing the discovery is written and submitted to an authoritative publication. The world’s best known general science publications are “Nature” in the UK and “Science” in the US. Papers submitted to these and even smaller, more specific, journals are then sent by the editors to a review panel of eminent scientists who specialise in the field discussed in the paper. If the consensus is that the paper has value, it is published. Scientists with a particular interest in the subject covered by the article then set out to duplicate the experiments described in the article to ensure they achieve identical results. If the results cannot be duplicated, warnings are sounded and the scientist in question is investigated. There are examples through history of scientific fraud. Peer review generally exposes it. Equally, scientists make mistakes and peer review generally picks them up and they are corrected. There are many examples of a paper being rewritten to correct errors found by the peer review. If only we could resubmit school exams to correct errors!
As a result of this rigour, we generally accept the veracity of science. Scientific discovery and invention fuel our economies and our lives.
So the discussion on climate change should not be about belief but whether the science is valid. Are the measurements correct as reported? Are the conclusions from those measurements valid? Are the projections reasonable?
The discussion should never descend to personal attack or a smear on any profession. It should concentrate on the information, validation and interpretation.
When I read of prominent people attacking scientists rather than their science, I am worried.
For example, Australia’s Federal Opposition leader, Tony Abbott, was reported in July 2011 making the following remarks: "It may well be, as you say, that most Australian economists think that the carbon tax or emissions trading scheme is the way to go. Maybe that’s a comment on the quality of our economists.’’
From the other side, former UK Prime Minister Gordon Brown has lashed out: “We mustn't be distracted by the behind-the-times, anti-science, flat-earth climate sceptics.”
Quite why either side needs to resort to name-calling or general put-down is beyond me. Surely we simply discuss the science as it is brought forward.
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In this discussion, I am going to group the scientists involved in the debate into “proponents” and “sceptics”. There are no “believers” nor “deniers”. Believers and deniers take absolute positions – rather like religious zealots and atheists.
There is an interesting book by Dan Gardner called “Future Babble” in which he sets out to show that those who predict the future are almost sure to be proved wrong by time. In fact, he claims, the more certain an individual or group is in their prediction, the more off the mark they are likely to be. Those who temper their predictions with qualification are more likely to be fairly accurate. Beware the extremists at either end of a debate.
There are three basic questions involved in the global warming debate:
1. Is the climate changing?
2. If it is changing, is it warming?
3. If it is warming, has human activity contributed to the change?
The answer to the first ought to be a simple yes. In fact, the climate undergoes constant change and has done so since the planet was formed and climate developed.
To the second question, even most of the scientists who disagree with the proposition of anthropogenic warming agree that the planet is warming. There is a significant argument about the degree of warming and the cause.
In 2008, Lord Christopher Monckton wrote in a report “CO2 enrichment will add little more than 1 °F (0.6 °C) to global mean surface temperature by 2100.”
Dr Roy Spencer, who holds a PhD in meteorology from the University of Wisconsin, says on his Web site that his research suggests that “global warming is mostly natural, and that the climate system is quite insensitive to humanity’s greenhouse gas emissions”.
Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change noted that climate model projections indicate that average global surface temperature is likely to rise a further 1.1 to 6.4 °C during the twenty-first century. If you want to gain a more detailed understanding of how scientists qualify their projections, follow this link!
Professor Bob Carter, an Australian geologist, environmental scientist and Emeritus Fellow at the Institute of Public Affairs, wrote in Quadrant magazine in March 2011: “Earth’s temperature is currently cooling slightly.”
He went further in an opinion piece for the Sydney Morning Herald in July 2011 when he wrote: “For example, the sun recently entered a quietude unknown since the Little Ice Age. Accompanying this, planetary warming has ceased despite still increasing carbon dioxide emissions. Some solar physicists have issued warnings that strong cooling may be imminent.”
In January 2011, the US National Aeronautical and Space Administration released a statement that “Global surface temperatures in 2010 tied 2005 as the warmest on record, according to an analysis by researchers at NASA's Goddard Institute for Space Studies (GISS) in New York.”
Confused?
Professor Carter and a few others aside, it seems that the third question is, in fact, the great debate.
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The problem in studying global temperatures is the extraordinary diversity of the planet. In Australia alone, the daily maximum can differ by 30 degrees Celsius depending upon where you are – Jindabyne or Cairns, for example.
Scientists use a variety of systems to capture global temperatures. The use of simple thermometers to gauge temperature around the world began in 1850. Weather balloons increased accuracy in the 1950s and today climate scientists rely on a vast number of weather stations around the globe as well as a number of satellites to monitor temperatures. For information before 1850, scientists have had to rely on local reports and on the classic tree ring analysis as well as sophisticated analysis of ice cores from the arctic and antarctic regions.
If you take the daily high and the daily low from all of these measuring devices around the world (both on land and at sea) for an entire century and average them out, the world’s mean temperature is about 14 degrees Celsius.
This little number may help us to understand what an increase of two or three degrees might mean. If you live in the tropics, an increase or decrease of two or three degrees in the daily maximum is barely noticed. At 30 or 32 degrees it’s still damn hot. But if you live somewhere where the average daily maximum is zero, an increase of two or three degrees has impact. For a start, the ice will start to melt!
In percentage terms, the change is also quite different. At 30 degrees, for example, a two degree increase amounts to a six percent change. But two degrees of top of 14 degrees is a relatively large 14.3 percent change.
The Australian Bureau of Meteorology records temperatures around the country all the time. It produced a graph for the final Garnaut Review on climate change that displayed temperature anomalies from 1910 through to the end of 2010. They took as their base the three decades from 1961 to 1990 (a base common with the World Meteorological Organisation), marking the average over that time at zero. Then it logged every year from 1910 against that marker.
Mean temperatures around Australia are remarkably stable given that we are used to daily temperature fluctuations of 10 degrees or more. In fact, only two years over that one hundred year span were more than one degree above or below the zero base – 1918 (below) and 2005 (above). The vast majority have varied by less than 0.5 degrees.
The graph shows that the years from 1910 to 1980 were predominantly below the average. In fact, only 11 years in that 70-year period recorded an average temperature above the zero base. Since 1980 only three years have been below the zero base; 2005 was the hottest at a little more than one degree above the zero base, with 2009 not far behind.
The graph shows the annual anomaly and also averages the anomalies by decade. Not surprisingly, every decade up to 1980 is below the zero base and every one beyond then is above. But the inexorable shift warmer can be seen to begin in the 1970s.
2010 is a curiously anomalous year, demonstrating that focus on one year or one region in one year is likely to be deeply misleading. The WMO shows 2010 to be the hottest on record (remember that accurate records for world temperatures begin in 1850), with 2005 and 1998 close behind. In Australia, 2010 was a mere 0.2 degrees above the zero base. It was one of the cooler years of the 21st century in Australia. This is a strong example of why we should never rely on temperatures in any one region, no matter how large, to make judgements about climate. In this case, it seems, Australia was an anomaly. Other countries will have their turn.
A lot has been said in the debate about 1998. The mean temperature, both in Australia and around the globe, spiked in that year well above the trend. In the years immediately after, the mean returned generally to the trend line. Some people have used that spike year to claim that the world has been cooling since 1998. Well, relative to 1998, the years 1999 through to 2004 were cooler. But one swallow does not make a spring (or summer). Scientists studying a subject quite so broad as climate should not choose to focus on a small group of years. To understand trends, a century is a better idea. A decade is likely to be misleading, let alone four or five or six.
An update on global temperature in 2011 was issued by NASA's Goddard Institute for Space Studies in January 2012.
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Is carbon dioxide a pollutant. No, it is not. It is a naturally occurring gas that is, in fact, vital to our existence. Our bodies need oxygen to survive. When we breathe in, our bodies absorb some of the oxygen in the air and put it to use. When we breathe out, we expel a range of gases including carbon dioxide. Fortunately, plants work in fairly much the opposite way. They ingest carbon dioxide in a process known as photosynthesis, storing the carbon and releasing the oxygen back into the atmosphere.
Carbon dioxide is one of the gases generally known as “greenhouse” gases because of their propensity to capture heat within the troposphere, the lowest layer of our atmosphere. Without greenhouse gases, our planet would freeze over (see above).
Water vapour is, in fact, a more potent greenhouse gas than CO2 and one that we can see and feel in action virtually every day. When there are no clouds (water vapour), the day is generally warmer. In fact, we can feel the difference when a cloud passes in front of the Sun. We can feel the temperature drop, even if just for a short time. We are in the shadow of the cloud as it absorbs the heat. Conversely, cloud at night keeps the atmosphere warmer than on a cloudless night. It traps the heat radiating out from the surface of the Earth.
Can a tiny amount of a gas in the atmosphere affect temperature on Earth? Water vapour does.
But can humans affect climate?
I lived in London for four years when I was in my 20s. Winter in England is cold and, in some ways, bleak. Snow falls through most of the country in winter. But it rarely snows in London itself. In fact, while I was there, Australians celebrated – to the amusement of locals – when we saw snow in London. It was a rare excitement. Yet snow falls regularly in the surrounding counties of Kent, Essex, Middlesex and Surrey. Why not often in London? The city – as many cities – generates an enormous amount of heat from the buildings, lights, business and sheer amount of humanity throughout the year. The heat is so great that it increases the ambient temperature immediately above and around. The phenomenon even has a name, the urban heat island.
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Bearing in mind the discussion above about the role of carbon dioxide in our existence, it is also worth noting that we have been cutting down trees and burning coal virtually since man emerged on the planet – first to keep ourselves warm and to cook food, then, as the industrial revolutions began, to power machines.
In fact, the industrial revolution began partly because of coal. From Roman times, Britons relied upon plentiful supplies of coal for heating and cooking. It was also used increasingly for smelting. At first, it could be found in outcrops on the surface. But, as people used it up, they had to start digging for supplies. By the late 1600s, miners in England had already dug up every bit of coal close to the surface and were having to dig deeper and deeper to find more. They eventually struck water tables and their mines filled with water. The demand for coal was such that a solution had to be found and Thomas Savery invented a crude steam engine to pump water in 1698. His invention was developed first by Thomas Newcomen and later by James Watt whose much improved engine fuelled the industrial revolution. The pace of digging up coal has exploded around the world through the 20th and 21st centuries.
Coal and oil are simply rotted and compressed plant matter – great stores of carbon. So, by the way, are diamonds.
At the same time as we consume increasing amounts of coal, we are clearing more trees and other vegetation. Professor Ron W. Nielsen has estimated that about half of the Earth's mature tropical forests - between 7.5 million and 8 million square kilometres of the original 15 million to 16 million square kilometres that until 1947 covered the planet - have now been destroyed (The Little Green Handbook). Paul F. Maycock, a forest ecologist at the University of Toronto, and others have predicted that, unless significant measures are taken on a worldwide basis, by 2030 there will be only 10 percent remaining.
By clearing trees, we are systematically reducing the amount of plant matter that undertakes the vital photosynthesis process by which the plants capture carbon and release oxygen. At the same time we are burning the coal and oil that has stored carbon for millions of years. Burning carbon creates – among other things – carbon dioxide. It seems to me that simple logic would suggest we are doing no good to the planet. At the one time we are doing the two things that will most promote an increase in carbon dioxide in the atmosphere; we are destroying the plants that absorb the gas and we are burning stored carbon (coal and oil) in vast quantities, releasing energy and gases including carbon dioxide.
Whether this and our emissions are enough to actually cause the entire planet to warm remain for analysis.
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Scientists on both sides of the debate generally agree that the planet is warming (see above and there are a bucket-load more citations). Professor Bob Carter is one among few who claim the planet has undergone cooling recently.
The degree of warming is debated. Whether that warming is a result of an increasing level of carbon dioxide in the atmosphere is also debated.
We have discussed that carbon dioxide and other greenhouse gases are vitally important in keeping this planet warm enough for us to live on. But is the level of carbon dioxide rising and, if so, by how much? If the level is rising, are humans responsible for the increase or could there be some other explanation?
C. David Keeling of the Scripps Institution of Oceanography began measuring levels of carbon dioxide in the atmosphere at a facility of the National Oceanic and Atmospheric Administration on Mauna Loa in Hawaii in 1958. Recording continues to this day. The record constitutes the longest record of such direct measurements in the world. One of the reasons for recording at this particular location is because it is a very long way from any potential source of man-made carbon dioxide. The level in 1958 was reported at 315 parts per million. In 2011 the level had grown to 390 parts per million, an increase over 53 years of 24 percent. The graph is a near straight line.
But does a rising level of carbon dioxide in the atmosphere coincide with rising global temperature?
The Mauna Loa record shows a steady increase in the level of atmospheric carbon dioxide. The Australian Bureau of Meteorology reports a rise in average temperature in Australia since the 1970s which generally coincides with records from around the world.
The two records seem to coincide, but does that mean they correlate?
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Carbon dioxide is a natural part of our atmosphere even thought it forms just a tiny percentage.
But how much is there and how does it get there and who – or what – is putting it there?
As we have stated, it forms about 390 parts per million in our atmosphere, or 0.039 percent of the total volume of gases in our atmosphere.
Atmospheric carbon dioxide comes from both natural and man-made sources.
The natural sources include the simple process of breathing. We and all other animals exhale a range of gases including carbon dioxide. Natural decay of plant and other organic matter emits huge amounts of carbon dioxide. Volcanos emit carbon dioxide during explosions.
On the man-made side of the ledger, burning fossil fuels emits carbon dioxide. When we run our cars, they emit carbon dioxide among a lot of other gases. Power stations emit carbon dioxide. As an aside, the great plumes we often see on TV screens are mainly water vapour, not carbon dioxide.
But we hear about hundreds of tonnes of gases. How on Earth does one weigh a gas? Of course, we should all remember from our high school science that everything has an atomic weight. Carbon dioxide is a molecule; one carbon atom and two oxygen atoms. It has a molecular weight of approximately 44.
If you are really curious, you can actually conduct an experiment to weigh carbon dioxide. I’m not sure you should try this at home!
So we now know carbon dioxide can be weighed.
What are the greatest sources of carbon dioxide?
Natural decay releases an estimated 220 gigatonnes of carbon dioxide into the atmosphere every year (a gigatonne is a billion tonnes). Estimates of global carbon dioxide emissions from all land and submarine volcanoes are between 130 and 440 million tonnes per year (Gerlach, 1991; Varekamp et al., 1992; Allard, 1992; Sano and Williams, 1996; Marty and Tolstikhin, 1998). In 2008, 31.8 gigatonnes of carbon dioxide were released from fossil fuels worldwide and land use change contributed 1.20 gigatonnes in 2008 (Global carbon budget 2009, University of East Anglia). Humans contribute about 2 gigatonnes. And there are all the animals. The good news about humans and animals is that we are considered a closed loop. Much of the carbon dioxide we exhale is simply a release from our food. The plants we eat have carbon stored through photosynthesis and the animals we eat also store some from the plants they eat!
We can’t prevent natural decay, we can’t plug the volcanoes and I don’t think any of us want to stop breathing! If we are to slow the increase in carbon dioxide in the atmosphere it seems we must turn to the two causes that we can control.
But do we want – or need – to slow the growth in atmospheric carbon dioxide?
The carbon dioxide in the atmosphere is not going to cause us health problems on its own. It is the potential for the gas – along with other greenhouse gases – to increase the atmospheric temperature that we need to consider.
By how much is the Earth atmosphere warming? Can we blame it on the increasing levels of carbon dioxide being detected in the atmosphere?
And will warming damage the planet and the systems we rely upon for a prosperous lifestyle?
Because, even if the planet is warming and even if the warming can be attributed to human activity but the warming is not materially going to affect our lifestyles – except to make Tasmania more comfortable and to wreck our ski fields – why should we act?
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