The basic science of the greenhouse effect is simple. The Sun
is hot so the light radiating out from it has most of its energy towards the blue and
violet end of the spectrum. The Earth catches a tiny amount of that
energy and gets warmed. For the Earth to maintain a stable
temperature it must radiate to outer space exactly the same amount of
energy as it receives from the Sun's radiation. Some energy
warming the Earth comes from
radioactive material, and tidal motion, but it is insignificant compared to sunlight.
Because the Earth is so much cooler than the Sun the energy it radiates
out to space is far into the infra red portion of the spectrum. Our eyes
cannot see it so we cannot see the influence greenhouse gases have.
They let the visible and ultraviolet rays in but trap some of the
infra red rays going out. If man increases the concentration of these
greenhouse gases (carbon dioxide and methane are the main ones we influence) then the delicate
equilibrium between the Sun and outer space is upset and our planet's
temperature will rise. There is no reasonable argument that can be made against this. The
only debate is about how serious the phenomena is.
I made the decision to devote my career to doing something practical
about global warming (GW) 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 to be worth worrying about.
Although I have put my effort into fixing the problem rather than
studying it I fully understand how computer programs 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 chemical 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. I used to believe another century of business as usual could do that! During 2013 new data came to my attention that is truly scary. Methane levels in the Arctic are shooting up and it is looking like it could be very difficult to stop it becoming ever faster. http://arctic-news.blogspot.co.uk/ The longer we delay taking serious action the more it will cost. If we delay too long we could all be dead by the middle of this century. The Stern review is famous for pointing out the cost of delays.
Even if we were not in danger of causing GW there is another factor that is also critically important. 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.
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 for how it could be fixed. We should not be motivated by fear, but the desire to create a pollution-free planet.
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 chance of the temperature ever getting as high as 50℃ or as low as -40℃ is 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
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 288 K. The Sun has an effective temperature of about 5780 K and Space has an effective temperature of 2.7 K. 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. 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 an accurate record 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 yet more the message that our activity is potentially very damaging.
The total greenhouse effect of our atmosphere causes a temperature rise of about 33 K. 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 stronger green house gas than water vapour so it contributes somewhere between 9 to 26% of the total warming even though its concentration is relatively low. Modern human activity has increased CO2 from 280 to 410 ppm and this has caused at least 0.9 K temperature rise already. If we magically stopped the rise and kept CO2 at the level it is now it would cause a further 0.5 K to 0.7 K 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.
Methane is about 25 times stronger than CO2 as a greenhouse gas if we take into account the fact that it gets removed from the atmosphere far more quickly. As the planet warms huge deposits of methane hydrates are in danger of decomposing. This could cause runaway warming that could be impossible for us to stop. It has been called the M-bomb for very good reason. It is critical that we stop this bomb being triggered.
In November 2007 the atmospheric CO2 concentration was 384 ppm, 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 280 ppm at the beginning of the industrial revolution. All life on earth has evolved to handle CO2 levels below 280 ppm. 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. First the dust from the impact would have cooled the Earth rapidly. When the dust settled after a few years the high CO 2 concentration would have caused Earth to warm up again. However, this warming lasted much longer than the cooling so the heat started killing the life that survived the brief cooling. This combination of rapid changes 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. Millions of years 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 280 ppm 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 10 or 20 years.
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.
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.
Since first starting this page in 2009 it has become apparent that there is actually a critically important factor missing from many models. The trouble is that it makes warming more dangerous. In fact so much more serious it challenges even my optimistic outlook. That factor is the vast deposits of methane hydrates that are starting to decompose. Methane hydrate is a solution of methane in ice and when it warms, or the pressure on it decreases, it melts yielding water and methane. Methane is more than 100 times as effective as CO2 as a greenhouse gas. The hydrate deposits are so huge they could put enough methane into the atmosphere to warm the planet by tens of degrees within decades. The process is like the detonator on a bomb. Methane release causes warming which causes more release. Release of methane also reduces the pressure on hydrate deposits below which makes them decompose even faster. The fact that the latest IPCC report (September 2013) dismisses this phenomena as low risk is criminal. Stopping the hydrate decomposition is going to be a massive challenge and the longer we leave it the harder it will get.
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 species 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 on many mountains there are distinct lines where the vegetation changes abruptly.
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 escape.
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 promoters
totally fail to understand is that the fossil fuel industry is worth
incomparably more and its gigantic profits are threatened by GW. In
2010 nine of the ten highest earning companies in the world earned
their money from
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 laws that promote their business. 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 eventually benefit. The dilemma
for those with a conscience within the fossil fuel industry is that
trillions have been invested in finding buried reserves worth even more
trillions. If they were to admit the seriousness of GW and agree to
leave this vast fortune in the ground the share value of their
companies would plummet. They need all the support and encouragement we
can give them to get honest and responsible.
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 feedback systems that are positive and they are starting to become more important.
I see our near-term salvation coming from mostly biochar, solar PV, wind power via kites 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.
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. In 2008 we received a warning of the need to reform our financial systems 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 deceit, and into reviving the economy by funding
clean renewable energy.
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 merely 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.
A widely quoted figure is that 97% of scientists agree that humans are causing GW (AGW). The primary source is this 2013 paper. http://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024/meta. They found that of the papers that expressed a position on AGW 97.1% endorsed the majority conclusion. However, 66.4% of papers did not express a position. Only 0.7% of the papers they reviewed rejected AGW. A newer study examined 38 papers that reject AGW and found that every single one contained errors fatal to their argument; https://futurism.com/3-of-scientific-papers-deny-climate-change-and-evidence-shows-they-are-flawed/ This paragraph is new to this web page in 2017 and since I wrote my last review I have learned a lot that dramatically increases my conviction that AGW is by far the most serious problem we face in the world today.
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 sceptic arguments.
Readers have commented on this page and selected correspondence is recorded in my global warming discussion and commentary page. There is also commentary on other pages about warming.
In my next essay I explain that good science is essentially honest observation; Scientific method
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