Posts Tagged ‘climate change’

Tipping Point

September 1, 2008

The Revenge of Gaia: Earth’s Climate Crisis and the Fate of Humanity
By James Lovelock
Basic Books (2007)

In this clarion call to arms, eminent scientist James Lovelock warns us cogently and eloquently of the impending doom that we have forced upon our planet by global warming. Lovelock is well-qualified to offer such gloomy predictions; it was this extremely versatile scientist who in the 1960s and 70s proposed the idea of Gaia, the notion that the earth is a self-regulating organism whose regulatory mechanisms are intimately coupled to the activities of species in its biosphere. One species- man- has tilted the balance of these mechanisms and thrown them into disarray. The species that will pay the biggest price for this deed is also man himself. Through careful speculation and excellent scientific arguments about details, he rationalized this notion until it has now become widely accepted.

Lovelock’s premier argument is that global warming (which he amusingly always refers to as “global heating”) has already rendered our planet incapable of the self-regulation that it has admirably demonstrated for millennia. The temperature rises which global warming are going to bring about are beyond those which the earth can endure in a homeostatic manner, and its catastrophic effects are likely going to manifest within decades. There is a horrific precedent for believing this; the same kinds of temperature rises fifty five million years ago led to catastrophic mass extinctions and sea-level rises, inducing an ice age that lasted 200,000 years. We are in danger of inducing such a global pandemic by our efforts right now. The most serious manifestation of man-made global warming is in positive feedback. Two examples suffice; the well-known melting of ice which leads to less reflection of sunlight which leads to more melting, and the heating of the upper layers of the ocean that kills algae. These algae are crucial players in maintaining cooling by the emission of sulfur compounds that serve to reflect sunlight from clouds. Lovelock documents both these effects well as well as others that are resulting from the ‘double whammy’ that we are serving our planet; simultaneously emitting CO2 and depriving the earth of biomass that normally absorbs it.

While the first part of the book describes Gaia and how it’s been affected irreversibly by global warming, the second part basically deals with the muddle headed perceptions of energy, food sources and environmentalism that affect many in the political establishment and media, most prominently environmentalists themselves.

There is clearly a rift between environmentalists that threatens to slow down action against climate change. One section, unfortunately the bigger one, is the more vocal one consisting of organizations like Greenpeace, who have a wrong-headed and irrational perception of environmentalism. They tout phrases like “sustainable development” and “renewables” without really understanding their limitations. They participate in emotion-laden protests and demonstrations just to prove their point. Their environmentalism mainly deals with trying to save cuddly creatures and colorful birds in remote parts of the world, while there are organisms much more in need of saving, including the microorganisms and algae which play extremely crucial roles in maintaining the homeostasis of Gaia.

The second group of environmentalists is a minority, and Lovelock is one of them. They understand that global warming has already done its damage and our goal now should not be mainly “sustainable development” but “sustainable retreat”. They understand that much more important than saving a few endangered species in New Guinea is to prevent deforestation and use of more landmass even in developing countries. They know that debate about saving the environment cannot be dictated by emotion. Most importantly they understand that nuclear energy is the best short-term and perhaps long-term solution for our energy needs.

When it comes to energy sources that we should pursue, Lovelock’s thesis is clear and rational. Renewables (solar, wind, biofuels) may sometime make a dent in the energy equation, but renewables are not going to save us soon enough. The phrase soon enough is important here. Lovelock is a reasonable man and does not discard renewables entirely. The problem is in trying to find good energy sources as fast as we can. But each one of the renewables is currently fraught with problems of inefficiency, environmental unfriendliness and lack of scale-up plans. Solar panels are expensive and inefficient. Wind farms consume huge tracts of land, land on which forestation usually soaks up carbon dioxide, and in addition need back up from fossil fuel generators when the wind is not blowing. Biofuels struggle with maintaining energy balances and pose similar land-use problems. It will be at least 50 years before renewables make a significant contribution to our energy needs and their use becomes cheap and widespread. But by that time it will be too late. The single-most important factor here is time.

The answer is clear and rational; especially for the short term future, nuclear power is the most efficient, readily available, widely-implementable, environment-friendly and safe source of power. Even if the problem of waste disposal is not trivial, it pales in comparison with the benefits we will incur, and especially the catastrophe that we will find ourselves in if we don’t do it.

While Lovelock hopes fusion will become important soon, fission is currently our best bet. We already have the technology unlike that for renewables. Its efficiency is marvelous- a good numerical argument to keep in mind is this; global CO2 emissions for a year make up a mountain that is a mile in diameter and sixteen miles in height, a behemoth. In contrast all the nuclear fuel providing power for a year will constitute a cube that is sixteen meters on a side. It was Lovelock’s espousal for nuclear power that represented a break from the ‘green’ party line. But now, nuclear is going to be as green as we can think of. To stave off fears of nuclear waste, Lovelock has even offered to bury the waste from a nuclear reactor in his backyard and use its energy for heating his house. In addition to these facts, Lovelock also clearly describes the paranoia that the public has for nuclear power, while all the time they face risks and dangers much more damaging and insidious.

One very cogent point that Lovelock makes is about how religious faith has caused problems in enabling our stewardship of the planet. He correctly points out that all religious texts were written at a time when man and his life were the focus. At very few places in the Bible or the Koran or even the Eastern texts is there an emphasis on the planet. None of the major world religions put nature before man. Now however, emphasizing man is going to be meaningless unless we emphasize Gaia, because without Gaia we won’t be around. There need to be new “religious” principles, infusing the care and stewardship of the planet into children’s minds, instead of the narrow self-serving interests of man that will become irrelevant once the sea-levels rise or the North Atlantic current slows down.

The same factor- time- that makes a good argument against renewables, also makes the strongest argument against libertarian “solutions” to climate change. Libertarians argue that the free market will eventually find solutions to the climate change problem without government intervention. But even if this solution might work in principle, ‘eventually’ is not going to be soon enough, good enough for us. We may have a little more than 20 years to beat a respectable retreat. For that we need legislation against carbon emissions, against use of oil for transportation, against land use right now. The libertarian approach may have worked 50 years ago when we had time. Thinking about renewable sources could have saved us if we had begun 200 years ago. But now even if these solutions work, they almost certainly will come too late to save us. As they say, “operation successful, but the patient is dead”. To save the patient in time, we are going to inevitably have to make compromises, sacrifice at least some of our freedom to large scale government actions. We have to operate now in a manner reminiscent of how we operate in wartime. In times of legitimate (and in these times I stress the word ‘legitimate’) war, citizens don’t complain about sacrificing freedom because they know their lives depend on it. Now Lovelock says we face a similar scenario.

It is very difficult to find wholesome solutions to climate change. We seem to have now done a good job of recognizing the problem in the first place. But unfortunately it’s too late to implement quick fixes that will wake us up from this nightmare when we will find that everything is all right. In an age where politicians are pushing for more oil drilling, rapid action and awareness is essential. We have to beat a retreat and live to fight another day, unlike Napoleon in Russia in 1812. For that we need coherent and rational thinking and global fixes, with all the compromises that they might entail. Going nuclear, and perhaps even indulging in grandiose fixes like “space reflectors” which reflect sunlight from miles-wide arrays, may be possibilities. Lovelock sounds an alarm in his book that is backed up by evidence and grim prognostication. Gaia will do whatever it takes to establish her equilibrium, equilibrium that’s inherent in the laws of her physics and chemistry, equilibrium that will be established even if it means the loss of humanity. As a pithy line in an X-Files episode once put it, “You can’t turn your back on nature, or nature will turn her back on you”. It’s simple.


Large-scale effects of a nuclear war between India and Pakistan

April 10, 2008

Back in the days when the Cold War was simmering, one of the rather depressing activities scientists and other officials used to engage in was to conjure up hypothetical scenarios involving nuclear war between the US and the Soviet Union and try to gauge its effects. Such theorizing was often done behind closed doors in enclaves like the RAND corporation. In the early 1960s, RAND’s Herman Kahn wrote an influential and morbid book called On Thermonuclear War. Kahn, a portly, overweight, brilliant Strangelovian character was said to be a possible inspiration for the good doctor in Kubrick’s brilliant movie Dr. Strangelove. In fact Kubrick supposedly read Kahn’s 600 page book in detail before working on the movie (A recent biography of Kahn sheds light on this fascinating man)

The book ignited a controversy about nuclear conflict because Kahn’s thesis was that nuclear war fought with thermonuclear weapons was survivable, thus possibly upping the ante for the nuclear powers. Kahn used many rather incomplete arguments to make the not entirely unreasonable point that while such a war would be horrific, it would not mean the end of humanity. The survivors may not necessarily envy the dead. But of course Kahn was speculating based on the then best available scientific data along with his own idiosyncratic biases. One of the biggest effects of a nuclear explosion is to send up debris in the atmosphere, and climate models in the 60s were in a primitive stage to help with predicting any such effects. Also, nuclear effects start wide-ranging fires and, in the rare cases where conditions are right, gruesome firestorms. Fires can account for up to 60% of the damage from a nuclear explosion. While the thermal effects constitute about 35% of the total effects from a typical nuclear air-burst (blast effects constitute about 50%), thermal effects can naturally sort of self-perpetuate through starting fires. According to some analysts, state department officials in the 50s calculating nuclear effects neglected the devastation due to fire, which made their results underestimates. Any realistic simulation of a nuclear explosion has to take into account effects due to fires.

The debate about the effects of a global thermonuclear war was galvanized in the 1980s when Carl Sagan and his colleagues proposed the idea of nuclear winter, in which dimming of sunlight because of the debris from nuclear explosions would lower the average temperature at the surface of the earth. Among other effects, this combined with the resulting darkness would devastate crops, thus bringing about long-term starvation and other catastrophes. Since then, scientists have been arguing back and forth about nuclear winter.

What has changed between 1980 and now though is that climate models including general circulation models have vastly improved and computational power to analyze them has exponentially gone up. Although we still cannot predict long-term climate, we now have a reasonably good handle on quantifying the various forcings and factors that affect climate. Thus for the last few years it has seemed worthwhile to predict the effect of nuclear war on our climate. Now scientists working at the University of Colorado and NOAA have come up with a rather disconcerting study in the Proceedings of the National Academy of Sciences indicating the effects of a regional nuclear war on global climate. A typical scenario is a war with 50 warheads of 15 kilotons each (about the yield of the Hiroshima bomb) between India and Pakistan, a conservative estimate. There have been a few such studies published earlier but this one looks at the effects on the ozone layer, the delicate veneer that protects life from UV radiation.

The researchers’ main argument is that there is a tremendous mass of soot that is kicked up tens of kilometers into the atmosphere during a nuclear explosion. The study seems to be carefully done, taking into account various factors acting to both reinforce and oppose the effects of this soot. The number they cite for the amount is about 5Tg (teragrams, a teragram being 10^12 grams) which is a huge number. They account for local fallout of the soot through rain as being about 20%. What happens to the remaining 4Tg is the main topic of investigation. According to the model, this enormous plume of soot is intensely heated by sunlight. By this time it has entered the upper layer of the troposphere and snakes up into the lower stratosphere where the ozone layer is situated, it is radiating heat that disrupts the delicate balance of chemical reactions that produce and get rid of ozone, reactions that have now been well-studied for decades. These involve the interaction of radical species of oxygen, nitrogen and halogens with ozone that sap the precious molecule away. The bottom line is that this heat from the hot soot vastly increases the rate of reactions that produce these species and eat up the ozone at that altitude, thus depleting the layer. The soot lingers around since removal mechanisms are slow at that height. The heat also encourages the formation of water vapour and its consequent break up and reaction with ozone, thus further contributing to the breakdown. The researchers also include circulation of water vapour and other gases in the global atmosphere, and how this circulation will be affected by the heat and the flow. Nitrogen oxides generated by natural and human processes have already been shown to deplete ozone, and the heated soot will also intensify the rate of these processes.

The frightening thing about the study is the magnitude of the predicted ozone loss due to these accelerated processes; about 20% globally, 40% at mid latitudes and up to 70% at high latitudes. Also, these losses would last for at least five years or so after the war. These are horrifying numbers. The ozone layer has evolved in a synergistic manner over hundreds of millions of years to wrap up life in a protective blanket and keep it safe. What would the loss of 40% of the ozone layer entail? The steep decline would allow low wavelength UV radiation which is currently almost completely blocked out to penetrate the biosphere. This deadly UV radiation would have large-scale devastating effects including rapid increases in cancer and perhaps irreversible changes in ecosystems, especially aquatic ones. The DNA effects documented by the researchers are appalling- up to 213% increases in DNA damage with respect to normal levels, with plant damage up to 132%. In addition, the increased UV light would hasten the normal decomposition of organic material, further contributing to the natural balance of the biosphere. The phenomenon would indeed be a global phenomenon. Decomposition of the soot is thought to be negligible.

Now I am no atmospheric scientist, but even if we assume that some of these estimates end up a little exaggerated, it still seems to me that effects on the ozone layer could be pretty serious. If I had to guess, I would think that there could be uncertainty in estimating how much soot is produced, how much goes up and to what altitude, and how long it stays there. What seems more certain are the effects on the well-studied radical reactions that deplete ozone. Some elementary facts seem to reinforce this in my mind- carbon has a very high sublimation point and can get heated up to high temperatures, the energy radiated by a hot body goes as the fourth power of the temperature, and from college chemistry I do remember the rule of thumb that on an average, the rate of a reaction doubles with a 10 degrees centigrade temperature rise. The estimates of rate increases made by the authors seem reasonable to me.

What is most disconcerting about the study is that it involves a rather “small” nuclear exchange that takes place in a localized part of a continent, and yet whose effects can affect the entire world. “Globalization” acquires a new and portentous meaning in this context. India and Pakistan can both easily field 50 weapons each of 15 kilotons yield, if not now, in the near future. In addition to this global-scale devastation of the ozone layer, it would be unthinkable to imagine the more than 10 million people dying in such a conflict, as well as total devastation of public systems and the food supply. Herman Kahn might have thought that nuclear war is “survivable”. Well, maybe not exactly…

Reference and abstract for those who are interested:
Mills, M.J., Toon, O.B., Turco, R.P., Kinnison, D.E., Garcia, R.R. (2008). Massive global ozone loss predicted following regional nuclear conflict. Proceedings of the National Academy of Sciences, 105(14), 5307-5312. DOI: 10.1073/pnas.0710058105

“We use a chemistry-climate model and new estimates of smoke produced by fires in contemporary cities to calculate the impact on stratospheric ozone of a regional nuclear war between developing nuclear states involving 100 Hiroshima-size bombs exploded in cities in the northern subtropics. We find column ozone losses in excess of 20% globally, 25–45% at midlatitudes, and 50–70% at northern high latitudes persisting for 5 years, with substantial losses continuing for 5 additional years. Column ozone amounts remain near or <220 Dobson units at all latitudes even after three years, constituting an extratropical “ozone hole.” The resulting increases in UV radiation could impact the biota significantly, including serious consequences for human health. The primary cause for the dramatic and persistent ozone depletion is heating of the stratosphere by smoke, which strongly absorbs solar radiation. The smoke-laden air rises to the upper stratosphere, where removal mechanisms are slow, so that much of the stratosphere is ultimately heated by the localized smoke injections. Higher stratospheric temperatures accelerate catalytic reaction cycles, particularly those of odd-nitrogen, which destroy ozone. In addition, the strong convection created by rising smoke plumes alters the stratospheric circulation, redistributing ozone and the sources of ozone-depleting gases, including N2O and chlorofluorocarbons. The ozone losses predicted here are significantly greater than previous “nuclear winter/UV spring” calculations, which did not adequately represent stratospheric plume rise. Our results point to previously unrecognized mechanisms for stratospheric ozone depletion.