Archive for the ‘climate change’ Category

This post is the occasion to continue the series of posts I initiated some time ago on the “let’s face the truth about climate change mitigation” theme. The ultimate goal of these posts is obviously not to suggest any definitive answer to the question: is it possible to mitigate climate change, only to give some insights into what can be done and would yield -to my humble opinion- effective results.

The AR4 WGIII published its results recently, and suggests clearly the extensive use of biofuels as part of the answer to climate change mitigation, in order to achieve CO2 emission reductions. The US launched this last couple of years a large program aiming at increasing significantly the production of biofuels (mainly from maize), and the EU also set targets for different time horizons: this topic has indeed become quite hot. This post will summarize the ideas expressed during two conferences I have attended to those past weeks. The first one left different speakers explain their opinion about the subject: Jeff Mc Neely, Chief Scientist World Conservation Union; Johan Hustad, Director, Center for renewable Energy NTNU-Sintef. The second conference was the third and last one organized this autumn by the department of Industrial Ecology of NTNU (cf this post for a comment about the previous conference, dealing with the results of the Working Group III of the IPCC).Our guest lecturer was Cameron Rennie, representing British Petroleum. He was Program Director for WBCSD’s Sustainable Livelihoods Program 2002-2005.

There are two key questions raised by the debate on biofuels:

  • Can biofuels represent a significant part of the energy market, and
  • Do they really yield greenhouse gases (GHG) savings, compared to conventional fossil fuels?

One can furthermore ask a third question, closely linked to the first one:

  • Can we produce both food for ouselves and food for our cars, in a sustainable way?

One has first to understand that biofuels are no technological breakthrough in themselves. Actually our ancestors used biomass (wood) to warm their caves, and today biomass is still used for 10,6% of the world’s primary energy production in 2002 [1], while renewables as most of us understand the word (ie wind, solar, hydro, etc…) represented then 7,8%. I do not consider nuclear as a renewable energy. So biomass is a common fuel for heat and power generation [2]. What is new with biofuels is that they are produced from biomass and transformed as liquid fuels that can be filled in the tank of our cars, in addition to or instead of common petrol or diesel.

To begin with, I would like to emphasize one point: we will never achieve a society based solely on biofuels. Simply because growing crops require fertilizers produced from oil, and because the world production would never be sufficient to feed both several billions individuals and their private cars. For example, to reach the 1997 global fuel production with biofuels only, 73 times the global stock of vegetation would be required. Biofuels are a complement to conventional oil; hopefully they will help towards a transition from oil to more sustainable energy sources. This way, Sweden has launched a pilot scale power plant running on willow, a plant growing commonly there. By expanding these methods throughout the country, their aim is to reach a fossil fuel-free society by 2025. Actually, the wood, pulp and paper industries account already for a substantial part of Sweden’s GDP (roughly 4%). The rise of the second generation of biofuels, based on lignocellulosic feedstock, could be a definitive advantage for this country that relies on sustainable production methods for forest management and resource exploitation [3].

But let’s go back to our introduction to biofuels. One can distinguish two types of liquid biofuels:

  1. bioalcohols, produced from sugar beet, corn, wheat, maize, sugar cane (leading to bioethanol), or woody wastes (methanol). This is a route chosen by the USA and Brazil, mainly.
  2. biodiesel, from palm oil, jatropha, rapeseed, sunflower amongst others; for example jatropha is grown in India.

Moreover, there are two generations of biofuels:

  1. the 1st one is based on agricultural crops, and might lead to ethical concerns related to the competition food/fuel. This is the one currently booming.
  2. the 2nd one is based on agricultural waste, wood and grasses. This generation is nevertheless still at the pilot scale and research is still going on in this field. The idea is to gasify the feedstock and produce different products from this synthetic gas.

You might have heard of the large deforestation that took place in Indonesia those last years: 9,8 m ha were lost in order to let 1,6 m ha of palm crops being grown. Environmentalists often accuse the biofuels industry for being responsible of this biodiversity destruction and CO2 release; nevertheless the truth is a small portion of palm oil production only is used for biofuels production; the huge majority is used to produce common oil one can find in food. Because of the environmental consequences of palm oil production, Sainsbury’s recently put a ban on products containing palm oil.

Now let’s go to technical details. How much energy is contained in a given quantity of biofuel? The following graph compares the specific energy content of different fuels.

Specific energy content of liquid biofuels

It appears clearly that different fuels do not have the same energy content. Oil has still the highest one, which is not surprising in itself, since it is a kind of concentrate of biomass. What is striking is that methanol and ethanol have a specific energy content nearly twice as low as crude oil; meaning that to get the same amount of energy from such fuels, twice the weight is needed when compared to oil. Olive and sunflower oil, on the contrary, reach almost the performance of crude oil. These oils are nevertheless not suitable for direct use in engines; although some people fill up their tanks with such products, the engine tends not to last very long… So one might argue that bioalcohols are not so interesting from a pure energy content point of view. Nevertheless, they are nowadays used commonly worldwide. Why? Because they can be burned in classical engines safely and without major technical fix, and their price is now competitive in front of oil, which price flirts with 100$ per barrel.

This is, I think, a reason for such a fast and enthusiastic development of liquid biofuels: it is merely a technological fix that does not force us to change radically our lifestyles. It is still possible to drive a common car with a few or no modifications (petrol/bioethanol mixes already exist and biofuels are nowadays common additives in the fuels available at filling stations). The core problem is not solved, only shifted elsewhere (to developing countries, mostly on a societal aspect as will be discussed later), or to the future (because GHG savings are not high enough to mitigate climate change).

Gaseous biofuels are an interesting alternative to natural gas. This option has already been chosen by Sweden, where some cities now have their public transportation network running on biogas (produced from anaerobic decomposition of household organic waste for example). This second graph shows that biogas has an advantage over natural gas: its energy content is slightly superior, and it is a renewable source of energy. Nevertheless, its use is limited by the efficiency of the waste management chain, and the availability of processing plants close to the using points.

Specific energy content of gaseous biofuels

Then comes the question of how much one fuel one can produce from agricultural crops. The US have for example chosen corn, Brazil sugarcane. Apart from the crop yields, and since the major (publicized) goal is to follow a carbon-free path, it can be interesting to compare how much one can harvest and transform into fuel first, and how much CO2 equivalent emissions are “saved” by the use of biofuels, compared to burning conventional oil. The answer to the first question points out clearly one thing: the US have chosen one of the worst ways. Corn actually leads to low yields, compared to other cultures (see next Figure); it is moreover not clear if it is beneficial to the environment as a whole, since raising corn requires large inputs of fertilizers and consumes enormous amounts of water. Furthermore, shortages of corn in the US for food (this product is subsidized, and that might be one reason for having chosen this route) have led to increased demand on the international level, hereby doubling the cost of the traditional tortillas in Mexico, as well as raising globally the price of cereals. As Monbiot writes in a recent essay,

The cost of rice has risen by 20% over the past year, maize by 50%, wheat by 100%. Biofuels aren’t entirely to blame – by taking land out of food production they exacerbate the effects of bad harvests and rising demand – but almost all the major agencies are now warning against expansion. And almost all the major governments are ignoring them.

Quantity of oil available per hectare cultivated

What are the actual CO2 savings? This question is tricky and is still subject to controversy. A survey [4] has shown that there is no definitive answer to this question since the savings depend on the technology used for growing the crops, the type of agricultural product chosen, and the geography itself. And as Monbiot states in his article, more and more publications demonstrate that the final result, when considering direct and indirect emissions related to production of biofuels (that is indeed the goal of Life Cycle Assessment), the final impact might be even negative compared to use of fossil liquid fuels, or even by simply protect the forests from clear cut [5]. But hey, a forest that is not exploited does not lead to profits, does it? So why would we protect it when it is possible to burn it, grow crops for fuels, and claim that we are green?

So seems the truth to be. Studies become more and more clearer: the first generation of biofuels does not solve the problems of energy security, of equity throughout the world and do not even lead to significant GHG reductions. The first generation of biofuels is just one more technological fix that fits to the current economic system requiring fast and reliable profits; with so many governments setting incentives for increase of the use of biofuels, as well as setting targets for the near future, the investors can find here a source of benefits as never before. In the meanwhile, people are dying in the developing world, become even poorer, and the climate continues its irreversible loop towards a complete disaster for our biosphere.

These targets have been for example set by the European countries, with different objectives for the 2010 horizon. The following Figure depicts the goals for 2010, as well as the achieved percentages of liquid biofuels in the transportation fuels. It has to be noticed that the goal for 2020 is 10%, which is obviously not attainable [6].

Targets for different European countries, 2010, and 2006 figures

To be rigorous, and because relying only on one side to get the information, it might be useful to know what the industry thinks about these issues of food and GHG savings. The conference given by Cameron Rennie provided with such an insight, and the point of view of someone that had worked for the World Business Council on Sustainable Development. But the arguments presented during his speech unfortunately did not provide the adequate picture of the reality; or it showed only one aspect of it. One can prove almost anything with numbers, if the reasoning is biased; only a thorough analysis of the arguments can sometimes underline the key error that opens to a deceptive truth.
I will not comment here on the motivation expressed by our lecture, “Putting the poor at the center of the value chain”, because this leads to the exploration of a more sociological aspect not relevant here; I will simply discuss some key slides that were shown.

  • First comes the question of food. As an answer, Mr. Rennie put out a graph showing the annual grain production in the US, which has been constantly rising since the beginning of the Green Revolution:

Yields in the US since 1890

Unfortunately for him, this graph does not seem to be relevant for me here. First, because it relates only what has happened in the US, which is far to be the case around the world; then because if this increase has been sustained, it is solely because of large inputs of by-products of the oil industry, that are expected to become more expensive as oil becomes a scarce resource; finally, seen on a worldwide scale (because it is at this scale that the biofuels market operates, isn’t it?), if the world grain production has increased, the per capita production has not at all followed the same pattern, as the following graph shows (sources: FAOSTAT for cereals production figures, and UN Population Division for the population).

Annual Per capita production of cereals, world, 1980-2005

As climate change will affect strongly the yields (Australia being already subject to crop losses), and the world population being expected to reach 9,2 billions by 2050, it is obvious that the per capita production of cereals will not increase much; rather decrease. So the argument of Mr Rennie does not resist further investigation: the first generation of biofuels does suffer from an ethical dilemma: should we feed our cars or feed the human species?

  • Concerning the GHG emissions, the only graph presented did not cite any source, or method used. Neither does it precise if these “savings” are direct reductions or cover the whole Well-to-Wheel chain (meaning the entire production chain, including production of the car, use, disposal, plus the fuel production chain). This should be stated clearly, as spotting out results without providing with any information on the methodology used can be perceived as suspicious. And as has been said previously, these results are still under discussion. To be even more critical, the 200g/km released taken as reference are above the 120g/km that a small European car would emit. So “savings” could actually be “losses”.

GHG emissions savings depending on the biofuel used

  • Finally, I will comment on the prospect that corporations have to include small farmers in the production of biofuels. Companies come to developing countries with experts that analyze the situation and declare that there is potential for substantial economic development, by shifting from traditional agricultural crops to biofuels crops. Nevertheless, due to the small fuel yields, no single peasant can grow enough crop to be economically profitable: biofuels require large-scale crops, meaning large infrastructure, and know-how that indigenous people seldom have. So the result is often destruction of the local traditional practices, as well as full dependence of the farmers on the international companies. It is unclear if the social benefits on the long term are real. At least profits are.

If you combine the increase of the oil prices and the increase of food prices then you have the elements of a very serious [social] crisis in the future,” Jacques Diouf, head of the FAO.

The competition for grain between the world’s 800 million motorists, who want to maintain their mobility, and its 2 billion poorest people, who are simply trying to survive, is emerging as an epic issue.” Lester Brown, founder of the Washington-based Worldwatch Institute think tank.

[1] Renewable Energy: Power for a sustainable future, 2nd ed., G. Boyle, 2004

[2] For a general overview of biomass and its use, have a look at this IEA publication

[3] Sweden produces 24% of its energy (2004) and more than 50% of its electricity (2005) from renewable resources, the major part coming from large-scale hydro. Source (in Swedish).

[4] “A review of LCA studies on liquid biofuel systems for the transport sector”, E.D. Larson, 2005

[5] “Carbon mitigation by Biofuels or by Saving and Restoring Forests?” R. Righelato, D.V. Spracklen, Science, September 2007

[6] “Biofuels Progress Report”, European Union, 2007

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Today seems to be the right day for publication of another synthesis of what has been available online in the newspapers this week.

For those interested in an even better review, covering the recent times and looking at different issues, I would recommend this post from Trinifar. Impressive but true.

I was astonished to discover three significant articles on the homepage of the Guardian Environment and Le Monde (in French): first, that a new report has acknowledged that the world oil production peaked recently, and that increasing gap between offer and demand will inevitably lead to catastrophic social and economical consequences (English version available there); then, that the UK was trying to withdraw from its commitment to reach 20% renewables by 2020 (an information confirmed the day after); finally, (see also here for a French version) that scientists have observed an increased rate of CO2 emissions since 2000, leading to faster and tougher environmental consequences. And today a new report reveals that our civilization and the world it lives in are in danger of disappearance. In a couple of number, it gives this (quoting from the Guardian)

· 45 thousand square miles of forest are lost across the world each year

· 60% of the world’s major rivers have been dammed or diverted

· 34%: the amount by which the world’s population has grown in the last 20 years

· 75 thousand people a year are killed by natural disasters

· 50%: The percentage by which populations of fresh fish have declined in 20 years

· 20%: How much the energy requirements of developed countries such as the United States have increased in the period

And in the meantime, when companies study new technologies, people are expressing their refusal to see large wind turbines developed and sold, on the excuse that it is visually disturbing. Well, one has to choose: whether we try to shift from fossil to renewable power, thus attempting to limit our greenhouse gases emissions (and accept a visual “insult”, which is to me acceptable given the other option), or we go on burning coal and gas and go to hell within a century. Fortunately, politics are beginning to address the question and locally things are changing. In France, this week after the “Grenelle of environment” talks, the government has agreed in partnership with environmental organizations to vote new laws aiming at setting the path to a more environmental-friendly society; although there is a lot left to do in order to actually achieve sustainability. It is too early to judge how these new measures will be implemented, but the example of UK is not a good one to be inspired.

Well, time for some synthesis: the news are accumulating, as they have always done, although at a higher rate now, and show that it is no longer merely our climate which is at stake. It is our whole civilization, and the majority of the biosphere on this planet (see here and there for examples) that are now threatened. And even though we thougt we would have 1-15 years to react and change the slope we have taken, it appears that all the scenarios imagined before have systematically been wrong, even the most pessimistic ones (here, concerning the Stern report), and see the above mentioned articles for the rising GHG emissions.

Unfortunately, as I often witness, people have two behaviors when confronted to the problem:

  • They do not know and prefer not to know about it. After all, we live in developed countries and it is far better to shift the problems to the other side of the globe rather than questioning our lifestyles
  • They deeply reckon that technology can solve everything. “Put your faith in humanity and in science”. Being a scientist, I totally disagree with this claim. It is not like switching off the light: finding new solutions or establishing new theories takes a lot of time. Implementing them worldwide takes even longer time. We are running out of time. Everything goes exponentially and we cannot afford to wait a couple of years more, because we will already have reached the tipping point. Or have we already?
  • As discussed previously on GIM, solving the carbon-rich energy might not be enough. Our problems lie much deeper in our society and our culture. Those who put their faith on science rather than considering the wider problem are only accepting to solve one factor, that might be overwhelmed by the others (like absolute consumption growth, population growth, and the associated resource depletion issues).

On Wednesday I attended a conference on the investments in renewable energies worldwide. A striking figure was the increase in investments the last 3 years: here is a graph of the amounts:

Investments in renewable technologies

The leading countries, depending on the origin of the fundings, are USA, Germany, Japan, and… China. Despite the gloomy award of being the largest GHG emitter worldwide, catching up the US at an incredible pace, they invest a lot in renewable technologies. The backside is that in spite of huge amounts invested, they still represent 10% of the total investments in energy. Meaning the rest goes to fossil energies. It is like buying tons of cigarettes although one would be in the final stage of a lung cancer… No hope to survive with it but still money flows. And as the following graph shows, it seems like too much faith is put on biofuels, while these are in their current version not adequate to solve both energy and food supply problems. Interestingly, the US and Brazil are among the largest investors in biofuels, seen from the Venture Capital/Private Funds source of investments (34 %).

Percentage of investments per energy source

So things are moving. We do not see it often because it happens locally; the US is the typical example. Things are moving but it might appear not to be enough, or maybe it’s already too late. But let’s hope and believe we can all wake up and gather.

One last comment about the articles above mentioned, dealing with the energy crisis bound to rise up in the coming decades. The one I read on Le Monde did not last very long on the web; after less than 24 hours published online it was moved into the archives, accessible only to paying customers; normally articles stay a couple of days or more online… I find it a pity that important articles like this one are not left at the forefront longer than that. In the meanwhile, I receive “last minute” exclusive mail to let me know that… Brazil will organize the soccer world cup.

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In the context of a series of conferences organized by the department of Industrial Ecology at NTNU, Norway, we had the honor and pleasure to welcome Mr. Leo Meyer on the 2nd of October, for a speech on the work of the working group III of the IPCC in its 4th assessment report. Mr. Meyer is the head of the technical support unit of this working group. In this article, I will comment on the functioning principles of the IPCC and address critically the different solutions proposed by the group, with respect to the IPAT equation.

At first was explained the principle of the IPCC; what his missions were and how governments would act in collaboration with the scientists working in this panel. I will stop at this point and pinpoint the fact that governments have an influence on what is finally published, but only when it comes to the Summary for Policymakers (SPM), a 30-pages long document offering a synthesis of the work otherwise published both in the final report and in the technical summary. This report has to be approved by all the 180 participating countries word by word, graph by graph, etc… A direct consequence is that this report might be a light version of the thicker ones, only presenting facts that do not clash against policies or mentalities of various governments. If you do not have time to read the longer reports, then go for the SPM ones, but be aware that they are diluted versions of the truth available elsewhere. Their content is nonetheless accepted by scientists chairing the working group.

It is often heard that the IPCC does not represent all the scientific community; that it does not give space to alternative theories. To understand this fact, one has to keep in mind what the ultimate goal of the panel is, and how it proceeds to achieve it. How are authors selected?

  1. Governments and institutes of the 180 member countries submit CVs
  2. the IPCC Bureau matches CVs against chosen subjects. Here a first “filter” is applied, so as to choose people from different geographical origins, and from different “schools”. This in order to avoid a unique view of the issues.
    1. The concept of different schools might be for example relevant when it comes to economy.
    2. The chosen ones are not only academics, but also experts from the industry, NGOs, etc
  3. 15 lead authors are chosen per chapter
  4. The co chairs, as well as the lead authors, can also invite authors

The IPCC is so to say summarizing the current scientific knowledge on the evolution of the climate and the science therein. Its goal is not to produce new papers, explain new facts. It is an assembly of experts whose task is to read a lot of peer-reviewed papers (meaning read and corrected by other scientists) and write a report on the state-of-the-art. All the results published by the IPCC are therefore already published in the literature; the sole purpose of the IPCC is to gather the data and make it available, and in a certain extent, more comprehensible to a larger public.

The working group III has the task of describing the strategies to adopt to mitigate climate change, based on the impacts published by the working group II. Although the latter are regional, the strategies to adopt are inherently to be applied worldwide. Some differences of strategy might appear, depending on the current state of economic development of the considered country; but in the end one striking pattern comes out from the report: what we have to fix is technology, and change our consumption patterns. These two points, and particularly the former, are recurrent in the report. To summarize, technologies exist, but have to be implemented. The group does not expect any technological breakthrough to happen in the form of the discovery of a new energy source; what can be done is improvement of the existing technologies.

An “economic fix” is required in order to boost the shift from fossil to renewables, through the establishment of a worldwide price on carbon. And in spite of the apparently opposite mentalities of “bottom-up” (techno-economic analysis) and “top-down” (integrated assessment analysis), it appears that each way to address the problem can lead to substantial reductions in CO2 emissions. The following two graphs represent the possible reductions in CO2 emissions achievable through the implementation of a worldwide carbon trading system, using each of the two above-mentioned approaches. Of course the reductions will depend on the price set on eq-CO2. Due to uncertainties, a low- and high end-of-range are shown in each case.

Effects of a tax on CO2 (Top Down case)

Effects of a tax on CO2 (Top Down case)

What is frightening is to realize that the maximum emission reduction that can be achieved through technological shift, helped economically by a price on carbon, is roughly 30 GtCO2-equivalent per year, in the best case envisioned by the projections. Looking a couple of pages further in the report, one realizes that in order to stabilize our atmosphere at CO2-eq concentrations between 450 and 500 ppm, the limit for containing the temperature rise below 2 degrees, we need to peak our emissions by 2015. Let’s say that is impossible. With China and India growing, as well as the other countries still desperately looking for extensive economic growth based on over-exploitation of resources, nobody will accept such a sudden shift in mentalities. Although the solution for mitigation is within reach, we prefer not to take it and go on the same path as before.

I recently commented on Growth is Madness! that the IPCC was not addressing the population growth problem, although it recognizes it as one of the main drivers of increasing GHG emissions:

the effect on global emissions of the decrease in global energy intensity (-33%) during 1970 to 2004 has been smaller than the combined effect of global per capita income growth (77%) and global population growth (69%); both drivers of increasing energy-related CO2 emissions.

Of course, this conference was the ideal occasion to ask the right person the right question. Unfortunately, someone else asked our lecturer about population before I could, and turned it in such a way that it sounded too extreme (one-birht policy was given as an example). Here follows the question that I would have asked:

The IPCC Working group III addresses only the two last terms in the famous equation I=PAT (Environmental Impact = Population*Consumption*Technology), dismissing the first one, namely population growth, although recognizing it as one of the main drivers of increased GHG emissions. The predictions summarized in limits to Growth thirty years ago are even more valid today than when the book was initially written. Indeed, the neo‐Malthusian movement is pushing towards addressing the first term of the equation. Recently, China stated that by controlling population growth, 300 million births had been avoided by 2005, leading to direct savings of 1,3 billion tones of emitted CO2 in 2005 alone. Why is the IPCC WG III not emphasizing more strongly this fact and does not introduce policies required to curb population growth, policies which could include aid to development, access to family planning, and women empowerment in developing countries? And if it is not considered as relevant by the group, then why?

In my question, I nevertheless made one error, which was also the key to the answer provided by Mr. Meyer: I implied that the IPCC was introducing policies. It is not its role. The IPCC has been created in order to give the political leaders some ideas about how to deal with the problem. The IPCC has to be “Policy relevant, not policy prescriptive”. That means that it cannot suggest new, radically different ways of solving the global warming issue rather than by choosing to solve the problem with the political, economical and technological tools that we use or have today. Indeed, population control, through the use of whichever policy, is not accepted by most of the countries member of the panel.

So the answer of our guest lecturer was the following: when it comes to such issues directly touching the population and the human beings, cultural, religious and political problems rise up and block any further discussion of the subject. If the IPCC report does not address the population issue, that is because it is not politically correct, or because it would be too provocative to certain cultures. This concern is thus left to others to address.

By avoiding such sensitive subjects, and despite the full acceptance of their importance, the experts are not even in the position to suggest policies or strategies that could help us to take care of the P factor. By leaving this aspect as an external variable nobody can do anything about, we are actually refusing to fully open our eyes, and make the inevitable crash even harder to support.

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I have been thinking about writing something on the climate deniers. They are so-called scientists, or other persons with the ability to reach the media and publish their ideas, who spend their time trying to convince people that Anthropogenic global warming (AGW, see this post) is indeed a myth, invented by governments and other scientists in order to make themselves heard and cause chaos in our society.
Well, first of all, I would say that sometimes the guys are no scientists. Or if they are, well, they may be PhD or professors in another field than climatology. But of course what they’ll put forward is their title. A critical point to identify deniers is that they are ready to use every single piece of paper, put it out of its context, and claim high and loud that this is another proof against AGW. Another common feature is to use papers that are not intended to deny anything, maybe to suggest new ideas, and put them at the front, yelling that here it is, a new theory denies AGW. Here is a recent example, analyzed by real climatologists.

Anyway, one question is “how can they express themselves so much if they are just isolated guys?”. That’s a good question. In fact, if let’s say 95% of the scientists studying global warming are favorable to an anthropogenic theory and the 5% left do not, then it would be normal to hear the latter only 5% of the time.

But that’s in a perfect world, where freedom of speech is respected, and more important, where an equal ability to express oneself is given to all. And two factors contribute to a violation of these rules. Lobbying and money. The first one leads corrupted governments to prevent scientists to express themselves on the subject. The second one allows huge corporations to fund groups whose goal is systematically to deny AGW. ExxonMobil is one of them. Recently, Friends of the Earth put online a video aiming at sensibilizing people about such facts. There is also a petition you can add your name to. Because in the US, corporations are forced by law to publish who they give money to. Not in Europe. So Exxon and others can give out money to any denial group, without even being bothered about what the public thinks about it. This aside, they are currently misleading the public by publishing advertisements on their “reduced GHG emissions” whereas they actually increase them. So sign it please, and show that you support such groups working to counterbalance the increasing power of corporations. Thanks.

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This post will be the first of a series, aiming at giving you a fair idea of what would be needed to effectively mitigate climate change. Let me first emphasize our core belief: global warming and the resultant climate change are anthropogenic, meaning human-induced. Some might argue that no, everything is a question of natural cycles, cosmic rays, God’s hand and who knows. For those, I’d advise some easy reading: the “Start here” page on a blog written by climatologists. But I’ll try to give you a brief description of the phenomena. The sources I use are wikipedia and the IPCC working group I report, 2007.

Sun radiates electromagnetic waves in a variety of wavelengths. For example, it radiates visible light, but also infrared and ultraviolet. Quantum mechanics predict that the exact distribution of the emitted radiation is given according to the sun’s temperature (5800 K), following a mathematical formula called Planck’s law. In reality, the black-body is just a model and the real spectra is slightly different. The figure on the left shows the solar radiation spectrum as seen from space (in yellow) and from the surface of the Earth (in red). The black body approximation is also shown, and one can notice that it fits well to the yellow curve.
Spectrum of the sunlight above the atmosphere and after its transmission

So when the sunlight arrives on Earth, some of the energy is reflected to space because the albedo of the Earth (albedo is comprised between 1 -total reflection of the incoming light- and 0 -complete absorption. Earth’s is now 0.31, but bound to decrease because of the polar caps melting), while some is transmitted through the atmosphere. The different components of our atmosphere fill absorb some energy in different frequencies, which explains that when you look at the red spectrum, measured at sea level, you do not have the same pattern as before.

The light then hits the ground and gives some energy to it, thereby decreasing its frequency (an electromagnetic wave with high energy has a high frequency, ie a short wavelength). It is then reflected to the atmosphere. A fraction will be emitted in space, but the major part of this reflected energy will be trapped and absorbed by the atmosphere and converted in heat. You will ask why this did not occur earlier, when the light went through the atmosphere the first time: that is because then it had a high energy content, with high frequencies! And molecules like CO2 are really effective at absorbing electromagnetic waves of low frequencies, rather than high ones.

So you get what is called the greenhouse effect. Without atmosphere, the temperature on Earth would be around -19 degrees Celsius, and of course no life could ever have developed in these conditions…

The concentration of CO2 in the atmosphere has increased during the last 150 years, because of human activity. Of course, the CO2 concentration follows cycles; sometimes it goes up, sometimes it goes down. The following figure shows the evolution of temperature and CO2 concentration during the last 450,000 years.

Evolution of CO2 concentration and temperature

What is striking is that temperature is strongly correlated to the concentration of CO2. Moreover, an increase in CO2 leads to an increase in temperature through radiative forcing, and a feedback exists: an increase in temperature leads for example to higher evaporation of water, which is by far the largest greenhouse gas present in the atmosphere, so in turn higher temperature, etc… Until a new equilibrium is reached.

There are several such positive feedbacks, although for us living species their effects might be considered as negative. Since it takes some time for the CO2 recently released in the atmosphere to have an effect, the worst is yet to come. The global atmospheric concentration of carbon dioxide has increased from a pre-industrial value of about 280 ppm to 379 ppm in 2005. Indeed, and as can be seen on the graph, the atmospheric concentration of carbon dioxide in 2005 exceeds by far the natural range over the last 650,000 years (180 to 300 ppm) as determined from ice cores. There is not only CO2 as greenhouse gas; the most common ones, besides carbon dioxide, are CH4 and N2O. Scientists have tried to put some “equivalent global warming potentials” (GWP) on these other molecules, compared to CO2. For example, CH4 has a GWP of 21, meaning that it is potentially 21 times more effective than CO2. And guess how much is GWP of N2O? 310.

Now, you mqybe wonder why the global atmospheric concentration of CO2 has increased recently. But you know the answer. Our society is based on the consumption of fossil fuels. Fossil fuels (coal, oil, gas) are remainings from carbon wastes such as plants and living organisms like animals, which died millions of years ago and progressively decayed and decomposed in the soil. Under certain temperature and pressure conditions, time helping, these wastes are transformed into fossil fuels. Indeed, they are composed of molecules based of carbon. Burning them in presence of oxygen leads to formation of CO2 and water (H2O), among other substances. And that’s where the extra atmospheric CO2 comes from.

This introduction was just a short explanation of the basic physical principles behind the greenhouse effect and its extension to anthropogenic global warming (AGW). My next post will expose the solutions the scientific community recommends for an “effective” mitigation of climate change. I put it between brackets, because it is not possible to stop AGW so easily. CO2 has a half-life of 12 years in the atmosphere, N2O of 120; that means that it will take maybe centuries for natural processes to come back to our original situation, just 150 years ago. Yeah, isn’t it powerful, destroy a 12,000 years long climatic equilibrium in 150 years?

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