Global warming

Introduction and background

By the 1970's I had become aware of the issue of global warming (GW) and the limited supply of fossil fuels and it seemed obvious to me that there was a problem. Using up the Earth's reserves of oil and gas millions of times faster than they were formed cannot go on forever. Whether it runs out in my lifetime or in 1000 years time it has always seemed to me that such rapid destruction of a limited resource is short-sighted and extremely selfish. I had already decided by then that I wanted to become an engineer so I decided to use that career choice to work towards a solution.

My school friend Roy and I wanted to enter a project into a prestigious science competition where some of our school mates had won valuable prizes. We decided to study batteries and while doing that project we discovered fuel cells. Fuel cells are power sources that are potentially far more efficient than combustion engines so I decided to devote my career to working on them. Although we did not win a grand prize at the competition the fact that we had entered helped me get a bursary from Union Carbide to study Chemical Engineering. Later in 1993 I finally got a chance to do fuel cell research full time. At first I thought I had found my calling and worked with huge enthusiasm to build what might have been the world's first solid oxide fuel cell powered car (photo above). The twist is that this project brought me to the realisation that fuel cells will only ever be a fairly small part of a complicated mix of energy sources. In the grand scheme of things that is not a problem but it did mean my enthusiasm declined and my interests have turned to wind energy, batteries for energy storage, and water purification. I now see our near-term salvation coming from solar power first, wind power second and then a complex mix of wave, tidal, geothermal, biological and other energy sources. We CAN stop polluting the World. All it will take is a commitment by enough people to make the changes required. It does not have to be a hardship if we embrace those changes and use them as an opportunity.

Why bother?

Because I made the decision to devote my career to doing something practical about global warming and pollution back in the 1970's I have kept an eye on research results about the subject ever since. I do not want to be working on something that turns out not be worth worrying about. Although I have put my effort into fixing the problem rather than studying it I weel understand how the computer programs that are used to model the climate. I know enough about the subject to detect when someone is talking the truth or not and whether they understand the science or not. Chemical Engineering is one of the best qualifications for studying climate because the chemcial plants we are trained to design and build rely on the same scientific principles.

The fact is that global warming is potentially far more serious than most people realise. We have the ability to kill all life on this planet. A business as usual strategy could do that! However, there is no need to worry too much because enough of us will wake up in time and do something about it. I am writing this page to hurry that process up because the longer we wait the more it will cost. The Stern review is famous for making that point. Delaying meaningful action will also contribute to extinction of species and that is a worse long-term tragedy than wasting money.

Even if we were not in danger of causing global warming there is another factor that to me is undeniable. Fossil fuels are limited and using them up cuts the options for future generations. If we limited our use of crude oil to the rate at which it was formed we would be able to run fewer than 1000 cars on the whole planet. Permaculture is based on the idea that we should only do things we can carry on doing indefinitely and I think that this needs to become a fundamental philosophy of all our material activities. Anything less is selfish and inconsiderate.

Myths about GW.

There are a number of dangerous misunderstandings that have been repeated far too often so I would like to help blow them away. I rub in the observations that many scientists fear to mention. I do that because I have a clear vision of how it could be fixed. We should not be motivated by fear, but the desire to create a pollution-free planet.

Myth 1; weather and climate modelling are the same

People frequently ask, "If we have no control over the weather, how could we have control over the climate", or, "If we cannot predict the weather next week how can we predict the climate in the next decade"? To answer this we need to understand something about the mathematics of chaos. This branch of mathematics only really took off when computers become commonly available. The Mandelbrot set and similar intriguing patterns are well known examples (picture below). Essentially what happens is that when we model a chaotic system, tiny changes in the starting conditions make huge changes in the result. The weather is a chaotic system. That is why we have the butterfly effect. Quite literally, the flapping of a butterfly's wings in South America could cause a storm in Europe a few years later. This would be alarming if it were not for another feature of real-life chaotic systems that is hardly ever mentioned. They are bounded by an envelope. This means that the weather is always contained within limits. For instance, in the UK the chances of the temperature ever getting as high as 50°C or as low as -40°C are so remote we can regard it as impossible. These extremes are nevertheless common in other places.

The long-term average of the weather (the climate) is modelled with computer programs that are different from those used to predict the weather for our daily forecasts. The science and mathematics are significantly different. The time steps used in the numerical climate models are far longer. Sceptics often quote trends over periods of 8 years or less. This is just the weather doing its chaotic thing. When considering the climate, the minimum period that makes sense is 11 years because this is the period of the dominant solar cycle.
mandelbrot set image

Myth 2; our production of Carbon Dioxide is insignificant

It is important to realise that the Earth's climate is very finely balanced. We have a very hot Sun heating us from one direction and we have a very cold Space cooling us from all other directions. The Earth is balanced between these extremes with an average surface temperature of about 288K. The Sun has an effective temperature of about 5780K and Space has an effective temperature of 2.7K. By using the absolute Kelvin scale of temperature it becomes clearer how delicately the Earth's temperature is balanced between these wide extremes.

The temperature of the Earth is primarily controlled by the effective temperature of the Sun and its distance from the Sun. Mercury is much closer and is too hot for life as we know it while Mars is further away and therefore colder. The evidence so far is that any changes in the Sun, or our orbit, will have less effect on the climate than the carbon dioxide (CO₂) we have already released. However, the ice-core data shows a regular cycle in Earth climate lasting about 100 000 years. Ice-core data comes from ancient ice fields around the globe and gives us by far the most accurate record we have of the climate going back 800 000 years. The regularity of past ice ages suggests that they are triggered by astronomical events but all the data about our orbit and the activity of the Sun show that these change very little. This reinforces the theory that the climate is on a delicate balance. Since the ice-core data shows that humanity in the last few decades has caused a change far more rapid than any seen in the last 0.8 million years it reinforces the message that our activity is potentially very damaging.

The next factor that warms our Earth by about 33K is the green house effect. Most of the warming is done by water vapour in the atmosphere and clouds are an important part of this. Predicting how atmospheric humidity and cloud cover will change is complicated but the models suggest that some areas already stressed by a shortage of fresh water will get worse, and this prediction appears to be happening already.

CO₂ is a much stronger green house gas than water so it causes significant warming even though its concentration is much lower. We have increased CO₂ from 280 to 390ppm and this has caused a 0.7K temperature rise already. If we magically stopped the rise and kept CO₂ at the level it is now it would cause a further 0.5K rise in temperature over the next 50 years. This time lag is an important factor to remember because it means that the climate changes the planet has already experienced are only the beginning.

Myth 3; Earth has survived climate change before

In November 2007 the atmospheric CO₂ concentration was 384ppm, up exactly 100 ppm from the 1832 level. For the previous 800 000 years it oscillated between 180 and 280 ppm on a roughly 100 000 year cycle. It only rose above 280ppm at the beginning of the industrial revolution. All life on earth has evolved to handle CO₂ levels below 280ppm. It has long lost the ability to handle the atmospheric and temperature extremes that the earth experienced much further into the past. We are already loosing species at an alarming rate. Corals and other sensitive creatures are clearly stressed. The loss of a species that has taken millions of years to evolve is a tragedy and it is vital to reverse this trend as soon as possible.

Going back many millions of years our methods for measuring CO₂ concentration are much less accurate. Although the indication is that CO₂ levels have been much higher than they are today this fact cannot be taken in isolation. Other things were also different. The main one is that the sun has been getting hotter. It was the observation that the earth's temperature has remained almost constant despite the changes in the sun that led James Lovelock to come up with his famous Gaia theory.

The fossil record shows clearly that there have been several (5) events that have caused the death of most life on Earth. Changes in atmospheric composition are strongly associated with these events. Do we really want to be responsible for another one?

Accumulated evidence now shows that an Asteroid impact in the Yucatan Peninsula region of Mexico 65 million years ago sent the carbon dioxide levels up to a level far higher than they had been for many millions of years previously. This means the life-forms on Earth at the time were stressed by this. The combination of factors killed all the dinosaurs and many plant species. They had been evolving for millions of years and were adapted to the conditions at the time and were not able to adapt quickly enough to the new conditions. After this event CO₂ levels dropped down again as new plant and animal species adapted and evolved. CO₂ levels were probably below present day levels by 30 million years ago. They may have even been below 280ppm by then. That is a long time for life to evolve and adapt. In terms of the climate and of the ability of life to adapt we have already caused an impact with a severity comparable with the asteroid 65 millions years ago. We could cause a more severe impact if we carry on business as usual for just another 20 or 30 years.

Myth 4; the advantages of global warming outweigh the disadvantages

Global warming will bring some advantages. People living in cold climates frequently say they welcome warming because it will make life easier and more comfortable for them. A more ethical attitude is to consider the whole planet and asses if the sum of advantages outweigh the sum of disadvantages. Humanity evolved in the hot tropics of Africa and those of us living in temperate or cold climates are effectively invasive aliens. The native animals and plants that have evolved to handle these climates would suffer if it got hot enough for us humans to feel more at home. In hot climates the humans and other life forms living there are already suffering from climate change.

Insurance companies have already experienced rises in claims due to an increased frequency of extreme weather events. These were predicted in the 1980s some 10 to 20 years before they started to become statistically significant. The fact that the climate modellers predicted this ahead of it happening is a strong vindication of the validity of their methods.

The cycle of past ice ages suggests that maybe we were heading for another one within the next 1000 years. The danger is that it is a fine balance and warming the planet too much would not just prevent an ice age but would cause over-heating. Everything in nature is balanced between opposing forces. To find out where that balance will be we have to put numbers to the forces. Climate scientists have been putting numbers into their equations for many decades now and they are getting increasingly worried about the results that are coming out. As our computers get faster they can model the climate more accurately and with each increase in precision it becomes more clear that an excess of CO₂ is a very dangerous result of business as usual.

Myth 5; the climate models have left out some important factor

There are many web pages and other publications claiming that the climate models developed by the IPCC, and other bodies, have left out various important factors. In most cases the factor chosen for comment has not been ignored and the author has failed to check what the models actually do model. Most articles also make no attempt to do the maths and prove that their particular "missing factor" is indeed important. Most of the remaining articles cover a subject that is under investigation. The history of climate modelling has been a steady trend of increasing certainty that man made CO₂ emissions are a serious danger.

To test the models they are used to predict past climate behaviour. As more and more factors are included accuracy increases and these tests are used as proof that the predictions are improved. These results also help identify what factors need more study so that more precise data can be fed into the models. For instance variations of the sun's strength are very important so there has been a sustained effort to understand the sun better so that we can predict its behaviour better. Past experience of doing experiments and putting the results from them into the models is that most refinements have made it more certain that we must radically cut our CO₂ emissions.

Myth 6; a 2°C or 3°C average rise in temperature will not do much damage

As mentioned above, weather is a chaotic system and the climate is largely about the envelope in which the weather operates. Climate is about average temperatures, rainfalls and wind strengths and also about maximum and minimums. These extremes dictate what sorts of plants and animals can live in a certain place. Every species has a temperature above which it cannot survive and another below which it cannot survive. There are also limits of rainfall outside of which it will die, and so on. That is why as you go up a mountain there are distinct lines where the vegetation and wild life changes.

If the climate changes slowly then the trees and other plants can re-seed themselves and move to accommodate this change. However, a tree that takes 200 years to mature and which can only spread its seeds a few hundred metres can only move very slowly. Climate change is already moving the "comfort zone" of many animals and plants faster than they can keep up.

The beautiful coral reefs found in many tropical seas are already suffering badly because of the increased concentration of CO₂ dissolved in the sea. The seas are getting more acidic and the corals have nowhere to go to to escape.

Myth 7; Al Gore is promoting the GW myth to get rich

This particular myth has gained popularity recently. Exactly how he is supposed to be making millions (some even claim billions) from promoting clean energy is never explained. What the myth promotors totally fail to understand is that the fossil fuel industry is worth incomparibly more and its gigantic profits are threatened by GW. In 2010 nine of the ten highest earning companies in the world were in fossil fuels or fossil fuel using vehicles. Those companies have so much influence it renders Al Gore, and others like him, totally inconsequential. All industries have a history of defending their status quo and lobbying for improved conditions. There is plentiful evidence that the oil and motor industries have done the same and regard GW as a major inconvenience. Hence the title of Al Gore's famous film. GW really is a very inconvenient truth. However, if we stop resisting change (which is always inevitable anyway) and embrace the new clean sources of energy we will all benefit.

Positive feedback

Because governments and scientists do not want to be alarmist the reports about the full extent of the dangers of global warming are rarely discussed. If we have no solution and no prospect of salvation they are afraid of causing panic by talking about the full extent of the dangers. My opinion is that there is a solution so I explain the dangers we face more vividly than many other commentators. I also believe that hiding the truth is never a good policy. It is hard to get humans to change their minds and we are faced with a situation where this is going to have to happen, so totally open and honest debate is essential.

So far the rate of increase of atmospheric CO₂ has been slowed by negative feedback systems. As we produce more carbon dioxide the sea has dissolved more. Certain types of rocks (silicates) can react with it when fresh surfaces are exposed by erosion. An increased rate of plant growth has absorbed more. These are negative feedback systems but they have a limited capacity. There are other positive feedback systems that are starting to become more important.

1) Hot water dissolves less gas than cold water so the rate of CO₂ going into the sea will decline as it heats up.

2) Water has a large latent heat of fusion. This means that the energy to melt ice is the same as the energy to heat water by 78K. The rapid recession of glaciers and ice-caps that we are seeing means that a lot of energy is being sunk into the process of melting the water without raising its temperature. Once that energy input has melted the ice it will start raising the temperature of the water and the Earth will heat up more rapidly.

3) The open ocean absorbs much more heat from the sun than ice and snow do. As the Arctic ice-cap recedes at an ever increasing rate the sea is absorbing more heat from the sun. Official predictions for the total removal of ice from the Arctic keep moving closer.

4) Corals carry out the vital function of turning carbon dioxide into chalk. The large chalk deposits around the world are one of the places where nature stored the CO₂ that used to be in the atmosphere long before humans evolved from the dinosaurs. Corals are sensitive and have already been damaged by the increased CO₂. If they are killed off their function of sequestering carbon will cease.

5) Global warming is already helping deserts such as the Sahara and Australia increase in size. Destruction of plant life by the increased areas of low rainfall will mean the world as a whole will see less net absorption of CO₂ into organic matter. The rapid deforestation of many areas (Amazon, Indonesia, Africa etc.) is adding to this problem.

6) Larger areas with a dry climate mean fewer clouds to reflect the Sun's heat into space. Deforestation decreases cloud cover. However, the higher global temperatures mean that on average there is more water in the atmosphere. This means the contribution to the green house effect from water could increase. It also means more floods.

7) The really big danger is methane hydrates. Methane and water at low temperatures and under high pressure combine together to form solid hydrates. Researchers have already noticed an increased rate of decomposition of these hydrates. When this happens methane is released into the air and it is something like 23 times worse for global warming than carbon dioxide. If we heat our planet up just a bit too much we will get a situation where we get a runaway release of methane. It could well get out of control to the extent that we would not be able to stop it at any price! As the planet gets hotter the methane would be released even faster until it could kill all life on earth! If you do not believe me read my essay about SETI. It really is incredibly serious, but I will repeat that if we act quickly and decisively we can avert our own extinction.

Solutions

If everyone pulled together to address the problem of CO₂ we could fix it and at the same time improve our quality of life. The only sacrifice we have to make is to change some of our habits and thinking. The way forward is to embrace a rapid change to totally renewable energy sources. Much of the required technology for exploiting solar, wind, and other clean energy sources has already been demonstrated. Once the production of these clean energy systems is sufficiently automated the price of energy will actually drop. Air pollution would also dramatically decrease. What a pleasure to see clean air over our major cities!

The important thing to understand is that there is a hill to climb first. While renewable energy devices are produced on a small scale there is no economy of scale and the prices remain high. There are numerous people with excellent ideas but they cannot get the funding to get their ideas mass-produced. Many, like me, struggle to get the funding to get any production going. There is talk of addressing this tragic issue but action is slow. I wish more people would take a stand and promote the development of new clean energy generators.

We need a change of mindset. Most wealth in the world today was created on the back of polluting technology. It means that there is a large vested interest in persisting with the old dirty ways. A big shake-up is required. In 2008 we received a warning shake in the form of the credit crunch. Instead of governments spending incredible sums of money supporting the very organisations that caused the problem they should have injected the funds into helping the victims of the deceipt and into reviving the economy by funding clean renewable energy.

Links

If this essay and the previous one have not convinced you of the need for action and our ability to do so and make a difference then there is an excellent film worth watching called Home. The website is http://www.homethemovie.org/ and the film (which is 1h 33min long) can also be seen at http://www.youtube.com/watch?v=jqxENMKaeCU&feature=watch-now-button&wide=1 .

Compared to what is known about climate, this page is mearly a brief summary. Spencer Weart's History of Climate Warming explains more about the progress of the science. Vicky Pope explains more about climate models in news.bbc.co.uk/1/hi/sci/tech/6320515.stm

What will climate change do to our planet? paints a scary picture about the dangers of not adopting clean energy fast enough.

After writing this essay I discovered that there is a very comprehensive source of information on the same theme at www.newscientist.com/article/dn11462-climate-change-a-guide-for-the-perplexed.html. No harm done; I say some things they have missed. Besides, as they point out, fixing GW is about creating sufficient political will to do something meaningful about it instead of silly arguments about what sort of light bulb to use. Lighting contributes less than 1% to our total carbon footprint. It is time for more scientists who understand the issues to speak out more.

Some comprehensive sources of climate science material I found more recently are http://www.aip.org/history/climate/index.html and www.skepticalscience.com/ and www.skepticalscience.com/argument.php has a comprehensive list of concise answers to common skeptic arguments.

In my next essay I explain that good science is essentially honest observation; Scientific method

Page first edition 15/02/2009, last updated 16/09/2011.

Copyright © Robert Copcutt 2011

Discussion

Tony; I notice that you refer to Carbon Dioxide as a Pollutant. This is something that Sceptics vigorously resist, saying it is a natural gas, colourless, odourless and not a pollutant.

Reply; My definition of a pollutant is any chemical that is around in a concentration high enough to do damage. Any chemical can be a pollutant! Any chemical in low enough concentrations is not a pollutant. This point needs stressing because there is too much talk of chemical A being OK while chemical B is toxic which leads to incorrect conclusions. It is usually just a case of nature having adapted to having more of A around than B. Talking of "toxicity" without also talking about appropriate concentration levels has caused enormous wasted effort and anxst as people try to eliminate chemicals just because they have been labelled toxic. There are millions of chemicals existing in the bodies of animals and plants, and in nature, and every one of them needs to be in the right place and in the right concentration to do its job properly. In our bodies CO₂ is present primarily in our lungs and blood and we are in trouble if the concentration goes too high, or too low. It is all about balance in our bodies as well as in the air we all have to breath. CO₂ has recently become a pollutant because we have put too much into the air.

Tony; Nearly all Sceptic scientists rebut computer models. Why? Because it is simply impossible to enter all the data, and it is too easy to cherry-pick, so the result is not science but politics.

Reply; There is indeed a sad history of modellers making "convenient" simplifications because it is true that not every factor can be taken into account. That is why it is important to follow the money trail because knowing who funded a piece of work usually reveals clues about its bias. However, computer models are now enabling us to make huge technological leaps. These days cars, aircraft , computers etc., are designed with a critical reliance on computer models. The programmers have refined their computer code to the point that it is easy to use and gives accurate results. Real physical prototypes are still built to refine the details and test new features but the computer is now essential in advancing most areas of science and engineering. It is no different with climate modelling. The climate models in the 70's and 80's made many simplifying assumptions and were criticised for it. Their predictions were nevertheless alarming enough to make other scientists take the results very seriously and huge amounts of work were done to refine the models. Numerous extremely sophisticated experiments were also done on Earth and in Space to measure anything that could possibly be important to the issue. Still the sceptics were not happy so very little was done to fix GW. Over 30 years was wasted because oil prices were low. (The oil crisis of the 1970's caused a spurt in developing clean energy systems. The oil exporting countries probably saw this progress and realised that they needed to keep prices low or else they would loose their market. Governments also banned research funding for some of the most promising areas. However, now in 2011 the cheap oil is running out so prices cannot be kept low any more.) One of the predictions from early models was more extreme weather events. Thirty or more years of studying but not fixing the GW problem has seen exactly this happen. The cost of the extra damage done would have paid for huge research programs into solar, wind, wave and other clean renewable energy sources. Every fossil fuelled power station being built today is drawing funds away from clean energy production and increasing the cost of fixing the problem of global warming gases when we finally have sufficient consensus about it being a problem.

It is a tragic fact of modern culture that lying, deception and falsification of reports is close to becoming the accepted norm. People do not know who to believe so vast amounts of time are wasted double checking things and exposing dishonesty. Having reviewed some of the global warming sceptic links you refer to I can see so much dishonesty in them it makes it hard to stick with it and make a full review. I am not saying some of the greens have been much better but there is no excuse for lying; it just delays meaningful progress.

Tony; Perhaps you would oblige me by telling me what precisely are your qualifications.

Reply; Blowing my own trumpet is something I am extremely uncomfortable with but since it seems to be so important to you I will explain why I feel qualified to comment on the global warming debate. I qualified as a Chemical Engineer (BSc and then MSc) at the University of Cape Town (UCT). I am proud of this because the standard was as high as anywhere in the world. I am in a good position to judge this because I have worked for 6 years at the University of Cambridge which was recently assessed as the best in the world. At UCT they kept the standard high by failing about half the original intake. In South Africa engineers have a far higher status than they do in the UK and my year attracted the best students in the whole of Southern Africa. In the UK I gained my PhD at Middlesex University. I then moved to Keele and then Cambridge and in both I was working directly for a Fellow of the Royal Society. The Royal Society has by far the most prestigious fellowship. I am not a professor because I have preferred to do practical hands-on research rather than lecture. I am not a fellow of any organisation because chasing labels is not my game.

Chemical Engineering arose because of the need to design complex chemical plants which have to be right first time. A large plant costs a huge amount to build and getting the design wrong can be extremely expensive to rectify. In these plants chemicals frequently have to be heated and cooled and reactions occur that make it very difficult to predict what temperature will be achieved in different parts of the process. We therefore spend a large part of our time looking at various heat transfer processes and making sure our mathematical models of temperature profiles are as accurate as possible. This is all very similar to climate modelling. In fact I propose that Chemical Engineers are better qualified to do climate modelling than any other profession.

Tony; There is no such thing as world climate – it just does not exist. But there is climate in regions. In all seriousness, otherwise seemingly intelligent men believe that by cutting back on the minuscule amount of Carbon Dioxide produced by man, that somehow or other they will affect the weather and the climate. Did I say the weather? Yes, I did, for they define climate as an average of weather, not my definition, theirs!

Reply; Think of the climate as a sort of envelope in which the weather operates. Within that envelope there is a probability that certain weather conditions will occur at different times of the year. Climate modellers divide the world into small sections and model the weather probabilities in each little section. To predict a global average temperature at a certain time they first predict the average temperature in each little area and then take an average. As computers become faster and as the data for the models becomes more accurate the accuracy of these models increases. In 1896 Arrhenius estimated that a doubling of CO₂ would cause a temperature rise of 5 to 6 °C using manual calculations with crude data. Modern but very conservative estimates by the IPCC are 2 to 4.5 °C. The physics of the infra-red absorption properties of CO₂ that make it a green house gas cannot be disputed and the fact that humanity is producing enough to make a difference to the weather is beyond doubt. The danger to life comes from the extremes of the envelope. As CO₂ levels rise the probability of extreme temperature events and storms and droughts increase and these events cause a huge value of economic damage. The cost of changing to non-polluting renewable energy generation would be less.

Tony; 600,000 years ago so I am lead to believe, the white cliffs of Dover were joined to the white cliffs of Normandy.

Reply; Besides evidence of large swings in the global temperature and CO₂ levels every 100 000 years or so there is also evidence of large swings in sea level. In an ice age huge volumes of ice collect at the poles and sea level drops many meters. A lower sea level might sound convenient but the low temperatures would be very inconvenient. England has been covered by glaciers before. Human activity has made that very unlikely for a very long time but we are in danger of going too far the other way producing tragic flooding of vast areas of low land.

The most probable cause of the 100 000 year cycle is the earth moving away from the Sun as a result of a very subtle feature of its orbit. The greater distance causes global cooling and the cooler sea dissolves more CO₂ so very slowly over many centuries the atmospheric CO₂ level drops and this results in less global warming so the temperature drops even more. As the earth moves towards the sun again in the next part of the cycle the sea releases some of the extra CO₂ it dissolved before and again a positive feedback occurs. This would explain why CO₂ level changes appear to lag temperature changes.

Doug; ... Ice floats and ice insulates, preventing the water below from cooling. Melting ice lets the water below cool. That is what causes the multidecadal oscillations. The ice PREVENTS the water below from cooling. Without the ice, the water evaporates and cools and radiates its heat out into space. Then when the water is sufficiently COOLED, the ice reforms. This is a ~30 year cycle. This has been well-known for many decades. So your runaway sea ice melt scenario is unfounded. ...

Reply; There are a number of cyclical variations within the oceans, some of them taking many decades to complete. This complicates prediction of the weather but does not have a big effect on climate modelling. It certainly gets nowhere near weakening the theory that global warming is a serious danger. The fact remains that we are loosing ice coverage from the planet. Loss of this reflective surface to expose less reflective surfaces underneath means more of the sun's energy is captured by the planet. Global warming is totally dominated by the radiation that passes through our atmosphere. The emissivity of the surfaces exposed to the sun and space determines how much energy stays and how much is reflected or radiated away. The heat conductivity of the surface materials makes a minimal difference. Snow and ice are very reflective but sea water captures most of the energy so the melting of the frozen surface layers is a positive feedback mechanism. Positive feedbacks mean we are storing up serious problems for the future. The insulating properties of the ice sheets only affect the local temperatures. It is the light absorption spectrum of CO₂ that makes it a green house gas and the passage of electromagnetic energy through our atmosphere and into space is what determines the average temperature of the planet. More CO₂ means more heat which means less ice which means more rapid heating.

Commentary

www.newscientist.com/article/mg20327151.300-sea-level-rise-its-worse-than-we-thought.html?full=true points out that sea levels rose 17 centimetres in the 20th century and that the rate of rise is increasing. The article goes into detail about recent studies of ice melting and water expansion and analyses likely future sea levels. The news needs to be taken seriously because our population density is greatest near the ocean and an estimated rise of 2 metres by the end of this century is starting to look conservative. This would cause devastating damage to coastal cities.

"How it all ends" by Greg Craven is an excellent video explaining the need to take action. We cannot be totally certain about how much our actions are affecting the climate, but we can decide what to do about the risks. The worst outcome of taking action is that we will waste money and reduce our material wealth. The worst consequence of taking no action is a complete disaster on numerous levels. Craven makes it clear that taking every possible action we can is the only sensible option. He has made a number of other videos to a similar high standard that he calls the expansion pack. God's will is recommended. He has recently released a book that should be well worth reading if it is up to the standard of his videos; What's the Worst That Could Happen?

Stephen Wilde has written a series of articles about climate. Here I am specifically commenting on Global Warming and Cooling - The Reality and The hot water bottle effect. Like most who question the importance of humanity's affect on the climate Wilde seems to dismiss the importance of mathematical modelling. What they do not seem to realise is that computer models are now extremely important tools that are indispensable for so many things we now take for granted. One quick example. In the days of communism in the Eastern block they did not have many computers so they designed their cars with slide rules and educated judgement. In the West cars have been designed using computer models for many years now. It is the countless billions of calculations done by the computers that allowed the cars made in the West to be so much better than those made in the Eastern block. In Wilde's articles he spends a lot of time stating facts that climate modellers are well aware of. The trouble is he does not appear to have done the sums so his judgement about what is important and what is not is poor. Climate modelling is about dividing the world up into thousands of blocks and then doing millions of sums about the climate in each block. By dividing the world up in such a way it is possible to get a more accurate overview of how the different factors influence each other. This cannot be done without a computer model. I have frequently been surprised at the results that came out of my computer models, but these unexpected results were usually shown to be correct when verified by real-world experiments. Until Wilde demonstrates a good understanding of numerical climate modelling, and has done some sums, I will have trouble respecting his opinions.

Open source model idea

Something that would be most useful would be an open source climate model that the public could run on their own computers. I have not done an exhaustive search so maybe such a thing exists already. Please let me know if there is one and I will put a link here. Such a program would allow people to see what is already included in the model. If their favourite system is left out they could try adding it and seeing what difference it makes.

www.co2science.org/ is a site with a huge amount of data which appears to me to have been cherry picked to disprove GW. For instance they have a database of American weather stations; thousands of them. You can pick them one at a time and they claim that on average you will see that there has been no net temperature increase since 1930. Well I picked 2 at random and they both showed a distinct temperature rise. This is a ploy used by many GW sceptic sites: - distract you with a mountain of data so that you have less time to study the bigger picture. I also picked an area from the Global Historical Climatology Network data set that roughly represented Africa since 1880. Again, a clear and steady(ish) rise in temperature was reported. From the Medieval Warm Period Project data set I again chose 2 examples at random. One suggested higher temperatures in medieval times than now and the other suggested it was cooler, but both showed an increase during the 20th century. How far do we want it to increase? The site also claims that more water in the atmosphere will cause more clouds which will reflect the sun's heat away from the earth. Well that might be true but cloud formation is complex and to my knowledge it is not yet certain if this is true. What is know for certain is that hotter air holds more water as a vapour invisible to the light our eyes can see but not in the infra-red. This will cause more GW; for certain. They also go into details about how to do an experiment that shows how a plant grows faster as the concentration of CO₂ rises and as temperature rises. Did they think professional biologists who study GW did not know this? Plants in the real world have to contend with more than just CO₂ and temperature rises. The spread of pests is one important factor this site seems to have neglected. In conclusion there is an impressive amount of data on this site but I do not trust it because there appears to be a strong bias in what they choose to highlight.

On October 16th, 2009 Adam Axvig posted a talk by Lord Christopher Monckton on www.mnfmi.org/ There is a slide show that goes with it that is important to download to follow everything being said. It starts off by stressing the importance of truth but unfortunately very quickly fails to follow its own guidelines. Monckton is extremely well informed so he has a mass of evidence about the faults with what has been said about global warming. There is no excuse for these faults because it enables AGW sceptics like Monckton to spin a story that plays into the hands of those wishing to continue making money from fossil fuels. By stressing the importance of truth he seems to be hoping to dull his audience's critical faculties and maybe prevent them noticing his own distortions. I don't make that accusation lightly but I know for a fact that what he says about the weakness of computer models is biased. He also falls for the classic AGW sceptic line of claiming that the concentration of CO₂ in the atmosphere is so small that it cannot make any difference. When it was discovered that tiny amounts of chlorofluorocarbons (CFC) in the air were causing a hole in the ozone layer decisive action was quickly taken. This was because the value of the CFC industry was not too big and alternatives were developed. The concentrations involved are more than 100 000 times lower than the concentration of CO₂ that is causing concern.

The problem with CO₂ is that the industries that put it into the atmosphere are absolutely huge and the alternatives are seen as inconvenient. They need not be, and Monckton has totally failed to see that. When he warns at the end of the talk about an imminent treaty to form a global government I am left wondering whether to believe him and get worried, or maybe he is trying to mislead us again. Taking the wrong action to combat AGW is just as bad as denying its danger in the first place. Monckton correctly states that the truth must dominate but his talk contained too much that I know to be wrong so I have trouble believing most other things he says.

One example. He said he had reviewed an impressively large number of papers about climate change and checked to see how many mentioned the Stefan–Boltzmann equation and found that none did. His implication was that the authors of these papers had not been aware of this equation and therefore their work was suspect. If you do not know about this equation it is hard to explain how naughty Monckton was to do this. The Stefan–Boltzmann equation is at the core of climate modelling and everyone in the field will be so familiar with it that there will rarely be a need to mention it. It is a simple equation and the only part of it that needs further study from climate modellers is the emissivity of surfaces. If Monckton had scanned for "emissivity" in all those papers he would have found a ton of references but that would have disproved his case so instead he chose to mislead those in the audience without sufficient background in the subject to see through his dishonesty.