Climate models

Although I often criticize numerical models, since they often don't manage to reproduce correctly the observations I am working on, I have to recognize the following statement by Mark Lynas:

"Nevertheless, many skeptics base their objections on the suspicion that models are somehow fiddled in advance to come up with the "right answers" by scientists eager for the next global warming grant - "you get out what you put in", as the old adage goes. But climate models do have an important grounding: they are based not on subjective judgments by their constructors but on the fundamental laws of physics. These observable physical laws, governing everything from convection within clouds to the reflectivity of sea ice, cannot be changed by anyone, whatever their politics. After all, models don't do anything magical. All they do is solve physical equations. All the processes of HadCM3, for instance, could theoretically be worked out by hand - except that it would then take centuries of human labor to complete one "model run". What computers do is speed up the process, just as pocket calculators speed up mathematics lessons in school.
No one, however, suggests that models are perfect. They all tend to come out with slightly different answers to the same question, a reflection of their varying design. The reason here is that some of the physical laws that underpin them are not known precisely. How clouds interact with the wider atmosphere is a big uncertainty, for example, so some cloud model parameters are best guesses. Nor is it known exactly how far sulphate "aerosols" - tiny particles of pollution blamed for "global dimming" - cool things down. But models are a useful tool and give a valuable insight into likely future conditions on this planet - something humanity has never had access to before. Unlike the oracles consulted by the ancients, models offer a way of divining the future based not on the miraculous visions of some unseen prophetess but on observable physical data."

Mark Lynas, Six degrees - our future on a hotter planet, chapter "three degrees".

The present task for climate scientists is to improve our understanding of the physical relationships between different processes and parts of the earth system that are still not known precisely, and not well represented in climate models, in order to reduce the uncertainties in the forecasts of our future climate, and check that some neglected processes may not hold big surprises! For example, the IPCC's 2007 report forecasts between 18 and 59 centimeters of sea level rise by 2100, but acknowledges that uncertainties about ice-sheet response time to global warming were not taken into account because the physical processes involved had not yet been studied enough to allow for a reliable assessment of their potential effects. Since the Greenland and West Antarctic ice sheets contain enough ice for a multi-meter sea level rise, understanding the physical processes controlling ice sheet stability is an urgent scientific question to address, with primordial societal relevance.

Mano

"D'une vie entière inutile, il n'y aura eu que l'amour qui brille".

Mano Solo, "Des années entières", Rentrer au port.

Mano, j'ai enfin eu le plaisir de te voir et t'entendre en concert ce soir.
Ta voix a rempli l'Olympia et ma tête.
Pas très sympa par contre d'avoir gueulé sur ce pauvre fan qui chantait a tue-tête avec toi... Mais bon, c'est ton caractère, c'est sûrement pour ça que tu nous ponds des chansons comme tu le fais!

Cleaning up after ourselves

"Fixing climate by taking carbon dioxide back out of the atmosphere is not the same as fixing climate by putting sulfur dioxide in. It is not "geoengineering". It is much more conservative than that. Our problem with carbon dioxide is an unintended consequence of a long series of fantastic inventions - from trains, planes, and automobiles to electric light, television, and computers - that have collectively liberated the citizens of industrialized countries from want and physical labor, lengthened their lives, and enriched them tremendously. Billions of people on Earth, the kind of people who must still carry their water from a distant well or their firewood from a distant copse, remain eager for that kind of liberation. The moral strain, if there is one, lies not in our having achieved what we have by burning fossil fuels; it lies in not taking responsibility for the consequences. That's what capturing CO2 out of the air does - in such a way, unlike SO2 injection, as to minimize the danger of further unintended consequences. It is not a "technical fix" that allows us to burn more fossil fuels, any more than sewage systems allow us to eat more. It is merely cleaning up after ourselves."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Fixing climate".

The greatest challenge

"The greatest challenge of man's future is to provide the energy needed to lift the world's population out of poverty without imposing a cost on the planet that neither humans nor the rest of its inhabitants can bear. The answer to the challenge is in part political and in part technological, but none of the possible technologies are ready. Over the next twenty years, say, we need a massive research program to get them ready - we need to be investing heavily in research into solar energy as well as carbon capture."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Fixing climate".

The biggest problem

"The biggest problem confronting the world, Lackner was deciding at that time, is not whether quarks could exist in a free, unconfined state outside the atomic nucleus - the question that had exercised his brain as a theoretical physicist, and that he pursues these days as a hobby, the way other men might go bowling. The biggest problem was environmental. Malthus and his followers were right: we are headed for a brick wall. But the wall our growing population would soon crash into was not, as the Malthusians thought, the limited resources of the planet. It was the limited ability of the planet's thin biosphere to sustain the environmental impact our growing population and spreading industry are inflicting on it.
Ultimately that problem came down to energy. "If we had cheap, clean, and copious energy, we could solve our problems about being sustainable," Lackner says. Unlike other energy sources, fossil fuels are cheap and copious right now. If we could just make them clean, they would be perfect."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Scrubbing the air".

As the title of this chapter suggests, Klaus Lackner thinks there is a solution: capturing CO2 out of the ambient air, and storing it as carbonates, the way nature does it with the weathering process, albeit at much too slow a rate to keep up with our emissions. As crazy as it may sound, some people have thought about it seriously, and are beginning to show it could be feasible. I'll make another post about it later, but I just would like to add here an excerpt from Lackner's 2003 Science paper ("A guide to CO2 sequestration"):
"CO2 is three times as heavy as fuel and therefore cannot be stored in cars or airplanes. CO2 from these sources will have to be released into the atmosphere and recaptured later. Currently, photosynthesis is the only practical form of air capture. Capture from air flowing over chemical sorbents - such as strong alkali solutions or activated carbon substrates - appears feasible but needs to be demonstrated. [...]
Because the atmosphere mixes rapidly, extraction at any site, however remote, could compensate for emissions from anywhere else. By decoupling power generation from sequestration, air capture would allow the existing fossil fuel-based energy infrastructure to live out its useful life; it would open remote disposal sites and even allow for the eventual reduction of atmospheric CO2 concentration."

Is nuclear the energy solution?

A rational critic of nuclear energy as a practical solution to our energy and global warming problem:

"It's a measure of how urgent the CO2 problem has become that some antinuclear environmentalists have lately been willing to reconsider their long-standing opposition. Nuclear power, as its proponents frequently remind us, has killed far fewer people than coal mining, not to mention pollution from coal-fired power plants. But that doesn't mean there aren't rational reasons to be skeptical of it. There is still no permanent disposal site anywhere on Earth for waste that will remain dangerously radioactive for thousands of years. And the fear that a proliferation of civilian power plants could promote the proliferation of nuclear weapons has only grown more acute since September 11, 2001. The huge expansion of nuclear power that would be necessary for it to contribute significantly to resolving the CO2 problem is, in our opinion, just not going to happen."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Green is not enough".

Quand le superflu passe avant l'essentiel

"Comment se résigner, quand on voit que le superflu des uns est sans limites, alors que l'essentiel des autres n'est même pas satisfait?"

Bande-annonce du Syndrôme du Titanic, de Nicolas Hulot et Jean-Albert Lièvre.

The carbon pie

A good explanation and discussion of the concept of carbon pie:

"Yet any realistic solution to the climate problem will have to resolve that conflict between the powerful drive to use fossil fuels and the real threat CO2 poses. One way to get an idea of both the scale of the problem and of what an equitable solution might look like is to think in terms of a "carbon pie". The pie represents the amount of CO2 we could still put into the atmosphere without disastrous effects. Its size is not easy to specify. We don't really know at what level the CO2 concentration will become truly dangerous - at what threshold the climate might shift so that rapid melting of the ice sheets becomes unavoidable, say, or the intensity of the drought in the American West is incompatible with the civilization we have built there. James Hansen, director of the NASA Goddard Institute for Space Studies in New York, puts the threshold at 450 parts per million. The Goddard climate model predicts a one-degree-Celsius warming from that concentration, and Hansen thinks a global average temperature one degree warmer than today is enough to threaten the long-term stability of the ice sheets.[...]
The drawback to setting that as a goal, however, is that it is probably not attainable.[...]
A more realistic goal would be 560 ppm - a doubling of pre-industrial CO2 - for which the middle-of-the-range climate-model forecast is a warming of three degrees Celsius. That would give us a carbon pie of 720 gigatons. How should the pie be sliced? The most equitable way would be for each country to get a slice proportional in size to its population. The industrialized countries as a group would then get around 20 percent of the pie, or 144 gigatons. At present they are emitting nearly 5 gigatons a year; at that rate, they will have eaten their pie in less than thirty years. Three decades to reduce their CO2 emissions to zero: that gives an idea of the challenge those countries face, if they want to take full responsibility for the consequences of their prosperity and do as much as possible - though much less than some researchers advocate - to protect the planet from dangerous climate change.
Clearly, the industrialized countries are not going to reduce their carbon emissions to zero in thirty years. Most of them are not even going to meet their much less challenging obligations under the Kyoto Protocol, which calls on them to reduce their emissions by 2012 to below the 1990 levels - on average 5 percent below. The United States, which signed but never ratified the 1997 protocol, has not even tried to reduce its CO2 emissions [...]. At the same time, one of the great shortcomings of the Kyoto Protocol, which conservative climate skeptics have stressed and which has become starkly evident in recent years, is that it placed no obligations on developing countries.
The carbon pie suggests a conceptual way out of this dilemma. It dramatizes the reality that any solution to the climate problem is going to require an overarching deal between industrialized and developing countries. In essence, the former will have to buy extra pieces of pie from the latter, to avoid the choice between protecting climate and torpedoing their economies. In return, the developing countries will get some kind of help with developing - ideally, in a way that helps alleviate rather than aggravate the CO2 problem. The bigger slices of pie that an equitable division would allot them would also allow them to use more fossil fuels for longer - which will in itself be an essential component of their development."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "Green is not enough".

I think if such an agreement were reached at the Copenhagen Climate Conference in December, it would be a very good thing both for reducing the threats of global warming (although one can argue that if we choose a limit above the threshold at which climate change becomes dangerous for our civilization, then our efforts will be vain) and for helping the developing countries to get most of its people out of poverty, by transferring some of the riches the industrialized countries have gathered thanks to fossil fuels to those who have not yet enjoyed their benefits. But let's hope that these people don't follow our bad example and pollute as much as we did as they are developing. We therefore also need to develop cleaner energy production systems and to transfer these technologies to the developing countries as soon as possible!

Don't poke an angry beast!

To all those global warming skeptics who have withdrawn from its denial to diminishing its threats, I would like to quote this:

"There is no proof that global warming will cause a megadrought, or a sudden sea-level rise for that matter. There is only a reasonable argument based on common sense - and on a metaphor. We have learned that Earth's climate has been capable of megadroughts and other extreme and abrupt fluctuations in the past, when given only a small push by the sun or by the Milankovic cycles. It seems prudent to avoid giving climate a big push. If you're in a tippy canoe, you shouldn't dance - that's Richard Alley's version of the metaphor. If you're living with an angry beast, you shouldn't poke it with a sharp stick - that's Broecker's own favorite."

Wallace Broecker and Robert Kunzig, "CO2 - Fixing Climate", chapter "The drying of the future".

Happiness

"He who has so little knowledge of human nature as to seek happiness by changing anything but his own disposition will waste his life in fruitless efforts."

Samuel Johnson, quoted by Ram Dass, Remember: Be Here Now, chapter "Cookbook for a sacred life", section "Drop out / cop out".