For my 2003 economics diary, go here.

Economics - 2004

John Baez

January 10, 2004

Global Warming Study Warns of Extinctions

Global warming could doom hundreds of land plants and animals to extinction over the next 50 years by marooning them in harsh, changed surroundings, scientists warn.

A new analysis enlisting scientists from 14 laboratories around the world found that more than one-third of 1,103 native species they studied could vanish or plunge to near-extinction by 2050.

The findings were published in the Jan. 8 issue of Nature.

• Chris D. Thomas et al, Extinction risk from climate change, Nature 427 (Jan. 8 2004) 145-148.

January 16, 2004

What does it mean to say that the survival of the whole colony is "more important" than that of the individual cells? This is actually a tricky question. But I think there should be some sort of reasonable answer. Maybe it goes something like this. The survival of an individual red blood cell (for example) is so dependent on the survival of its "host" that a Darwinian explanation of what red blood cells do is simpler if we invoke the need for the host to reproduce than if we think of the host as a mere "complicated trick for red blood cells to reproduce themselves". The idea here is that what is "important" is that which helps us create a simple model of the situation.

One reason I'm interested in this issue is that evolution can be thought of as a kind of "game" - but not a game in the simple von Neumann-Morgenstern sense, in which there is a well-defined set of players who each choose among a well-defined set of strategies and each try to maximize a specific well-defined function. Instead, it's a "game" in which every type of entity seeks to maximize the number of entities of that type!

Here I say "seeks" in a somewhat anthropomorphizing way, but all I really mean is this: we find more of those entities whose nature is such that they tend to become common - the simple yet powerful tautology of natural selection. And when I say "every entity", I really mean every entity, from hydrogen atoms, to specific sequences of base pairs, to mitochondria, to red blood cells, to horses, to corporations, and so on.

Of course, this is taking evolution in a very broad sense - a sense that some people find too broad to be useful, but that's just the mood I'm in now. And when we think of it this broadly, we see that there are a lot of choices to be made in giving an evolutionary explanation of what's going on.

Most fundamental, perhaps is choosing the set of evolutionary "players" - the "replicators", the "units of selection", or whatever. This choice is not always clear: witness the argument between those who favor explanations in terms of "the selfish gene" and those who don't - or between those who find "memes" persuasive, and those who don't. Different ways of parsing the world in terms of "players" may prove more cogent in different contexts, and the issue is most fascinating to me here precisely when it's hardest to make up ones mind! So, I'd like to see work on "games with ill-defined players". In particular, it would be interesting to learn about games in which coalitions of players can become so tightly bound that it may become simpler to treat them as individual players, which in turn can form higher-level coalitions, and so on - but where players at any level still can and do "defect".

Believe it or not, I started writing this tonight because I wanted to raise the question: If corporations gradually replaced people as the fundamental "actors" in politics, how would we notice? Indeed, could it have already happened long ago? Already in 1886, the United States Supreme Court ruled that corporations count as legal "persons" with 14th Amendment rights to due process. By now one could argue that they control more of the political process than individual humans do, and that even CEOs are to a large extent only "powerful" to the extent that their objectives match those that corporations are optimized for: doing whatever it takes to bring in money in the form of profits and investment.

And the reason I wanted to raise this was the recent flurry of news, shortly before taxes are due in the USA this year, about how little income tax corporations pay compared to individual citizens! Part of this came from a report by the Government Accounting Office showing that in the years 1996 through 2000, roughly 60 percent of U.S.-based corporations paid no corporate income tax at all. About 94 percent of US corporations reported tax liabilities of less than 5 percent of their income in 2000. And US companies paid an average of 1.188 cents in tax for every dollar in gross receipts! The corporate income tax is supposedly 35 percent, but there are so many deductions and other loopholes that this is completely meaningless.

Naturally, people are outraged... but will anything happen? Don't count on it. Given how lobbying and elections work these days, people may be less important in making decisions about the tax code than corporations are. Who listens to a measly red blood cell?

Here is the GAO report:

• Tax Administation: Comparison of the Reported Tax Liabilities of Foreign- and U.S.-Controlled Corporations, 1996-2000, Government Accounting Office, USA

Amusingly, it seems to have been commissioned (or at least promoted) by Senator Dorgan in order to show that foreign-owned corporations pay less US income tax than US-owned corporations. For example, about 70 percent of foreign-owned corporations pay no US income tax, as opposed to 60 percent of US-owned ones. But, most people have found the difference less shocking than the fact that so few of any sort of corporation pays income tax! So, the nationalistic motive behind the report seems to have backfired.

William Greider has written some popular ruminations about the takeover of US politics by corporations:

• William Greider, Who Will Tell the People?: The Betrayal of American Democracy, Touchstone Books, 1993.
• William Greider, One World Ready or Not: The Manic Logic of Global Capitalism, Touchstone Books, 1998.

• William Greider, The Soul of Capitalism: Opening Paths to a Moral Economy, Simon and Schuster, 2003.

• Lynn Margulis, Origin of Eukaryotic Cells: Evidence and Research Implications for a Theory of the Origin and Evolution of Microbial, Plant, and Animal Cells, Yale U. Press, 1970.
• Lynn Margulis, Symbiosis in Cell Evolution: Microbial Communities in the Archean and Proterozoic Eons, 2nd edition, W. H. Freeman, New York, 1992.

You say that you want to understand more about economics.

Briefly, the market is an institution for encouraging creativity and criticism. States fundamentally differ from corporations in only one respect. States can levy taxes - you must pay them or be fined go to jail. (Well, the more benevolent states do this, other states openly commit murder, robbery and extortion on a regular basis.) Corporations cannot - you can stop buying their stuff if you don't like any aspect of their policies. States deprive people of choice, corporations do not.

To properly understand the issues involved I recommend:

'Individualism and Economic Order' and 'The Counter-Revolution of Science' by F. A. Hayek. As a sample:

http://www.fahayek.org/index.php?article=209

http://www.fahayek.org/index.php?article=74

'Conjectures and Refutations' and 'The Open Society and Its Enemies' by Karl Popper.

After that

'Price Theory' by David Friedman

http://www.daviddfriedman.com/Academic/Price_Theory/PThy_ToC.html

and the books of Lawrence Boland

http://www.sfu.ca/~boland/

David Friedman's book 'The Machinery of Freedom' and these articles on conspiracy theories are also relevant:

http://www.settingtheworldtorights.com/node.php?id=202

Finally, 'The Skeptical Environmentalist' by Bjørn Lomborg and 'the Ultimate Resource' by Julian Simon.

Alan

> States deprive people of choice, corporations do not.

Actually, any powerful institution inherently gives people certain choices while depriving them of others. And if you don't like what a corporation is doing, this solution:

> you can stop buying their stuff if you don't like any aspect of their
> policies. 

is often less effective than complaining loudly and forcefully. After all, there's no way a corporation can tell what you don't like simply from the fact that you don't buy their products!

For example, companies like Nike are more likely to improve the labor conditions in their sweatshops in response to public shaming than just from you and I ceasing to buy their goods - if we do the latter, they may assume we just don't like their sneakers.

In short, I don't think maximizing freedom for corporations, while reducing my means of expression to mere "buying or not buying", will make the world the best possible place.

Best,
jb

As for "The Skeptical Environmentalist", maybe I'll talk about that some other time.

• Kenneth R. Mount and Stanley Reiter, Computation and Complexity in Economic Behavior and Organization, Cambridge U. Press, Cambridge, 2002.

  Reviewed by Stephen J. DeCano in the Bulletin of the American Mathematical Society 41 (January 2004), 117-120.

Broadly stated, the task is to replace the global rationality of economic man with a kind of rational behavior that is compatible with the access to information and the computational capacities that are actually possessed by organisms, including man, in the kinds of environments in which such organisms exist.

I should read this book! It sounds interesting. However, I find the reviewer of this book (Stephen DeCano) has curious opinions about what a successful economic theory should achieve. I have a feeling they're commonly held. If so, I think they should be called into question. He starts as follows:

Economics has traditionally sought its defining restrictions through the imposition of a strict kind of rationality on the agents who populate its models. (Optimization of production and maximization of utility can be thought of as particular consequences of rationality.) Unfortunately, modern economic theory shows that rationality alone does not provide enought structure to model real-world phenomena adequately.

The classical tradition in economics stretching back to Adam Smith and culminating in neoclassical General Equilibrium Theory aims to derive the essential characteristics of the market economy from underlying fundamentals of tastes and technology, but even though rationality is enough to guarantee the existence of an equilibrium, it cannot rule out multiple equilibria and unstable dynamics.

I also don't see why a good theory should "guarantee the existence of an equilibrium". The world is not in equilibrium! It never has been, and never will be. The appeal of "equilibrium" in economics must stem from its simplicity rather than the desire to fit empirical data. Of course, simplified models can be enlightening even when not completely realistic - as long as we don't use them to make policy decisions. But even if we imagine a fantasy world where "tastes and technology" are held fixed, I can't imagine people settling down into some eternally unchanging equilibrium behavior. They would still jockey for advantage, forming cartels and coalitions that last for a while but then break down under the weight of their own success, and so on. I bet one can see this even in fairly simple real-world multi-person games! No?

Guess who said this:

"No one can be comfortable at the prospect of continuing to pump out the amounts of carbon dioxide that we are at present. People are going to go on allowing this atmospheric carbon dioxide to build up, with consequences that we really can't predict, but are probably not good.

He believes the solution is something called sequestration, in which carbon dioxide from cars and power stations is captured and stored. "Sequestration is difficult," he says. "But if we don't have sequestration I see very little hope for the world."

"You're right, the timescale might be impossible. In which case I'm really very worried for the planet."

More surprisingly, even the Bush administration is finally admitting the reality of global warming caused by manmade greenhouse gases! On Friday August 27, the International Herald Tribune wrote:

In a striking shift in the way the Bush administration has portrayed the science of climate change, a new report to Congress focuses on federal research indicating that emissions of carbon dioxide and other heat-trapping gases are the only likely explanation for global warming over the past three decades.

In delivering the report to Congress, an administration official, James Mahoney, said on Wednesday that it reflected the "best possible scientific information" on climate change.

[....]

U.S. and international panels of experts concluded as early as 2001 that smokestack and tailpipe discharges were the most likely cause of recent global warming. But the White House had disputed those conclusions.

The last time the administration issued a document suggesting that global warming had a human cause and posted big risks was in June 2002, in a submission to the United Nations under a climate treaty. Bush distanced himself from it, saying it was something "put out by the bureaucracy."

That approach may be harder to take this time. The new report, online at www.climatescience.gov, is accompanied by a letter signed by Bush's secretaries of energy and commerce and signed by his science advisor.

For the scientific consensus on global warming, see the Intergovernmental Panel on Climate Change website.

I've just started reading a book which puts the current mass extinction in an interesting perspective:

• Michael J. Benton, When Life Nearly Died: The Greatest Mass Extinction of All Time, Thames and Hudson, 2003.

I think almost everyone nowadays blames the death of the dinosaurs on an asteroid impact about 65 million years ago. This asteroid was about 10 kilometers in diameter, and it slammed into shallow waters covering what is now the Yucatan peninsula. The resulting crater, called Chicxulub or "Tail of the Devil", is about 150 kilometers across! The resulting tsunami would have hit Texas with a wave 50 to 100 meters high. Millions of tons of material were hurled into the atmosphere, causing wildfires across the world as they landed. Rocks called "tektites" formed from droplets of molten quartz can be found as far as Wyoming. A layer of dust from the impact can be found in rocks world-wide, marking the boundary between the Cretaceous and Tertiary. Scientists guess that this dust made it too dark to see for 1 to 6 months, and too dark for photosynthesis for sometime between 2 months and a year. Carbon dioxide released from heated limestone would have also had effects on the climate.

But this disaster at the end of the Cretaceous was only one of the really big mass extinctions, including these, which are called the "Big Five":

• The Ordovician-Silurian Extinction, 440-450 million years ago at the end of the Ordovician Period.

  This was the second biggest extinction of marine life, ranking only below the Permian extinction. There was only life in the seas at this time, and more than one hundred families of marine invertebrates died, including two-thirds of all brachiopod and bryozoan families. One theory is that as the continent Gondwana drifted over the north pole, there was a phase of global cooling, and so much glaciation took place that sea levels were drastically lowered.

• The Devonian Extinction, 375 million years ago at the end of the Frasnian Age in the middle of the Devonian Period.

  By this point there were plants, insects and amphibians on land, fish in the seas, and huge reefs built by corals and stromatoporoids. The extinction seems to have only affected marine life, but 70% of marine species went extinct! Reef-building organisms were almost completely wiped out, so that coral reefs returned only with the development of modern corals in the Mesozoic. Brachiopods, trilobites, and other sorts got hit hard. Since warm water species were the most severely affected, many scientists suspect another bout of global cooling. There may have also been a meteorite impact, but it seems this was not a suffden event.

• The Permian-Triassic Extinction, 251 million years ago at the end of the Permian Period.

  Before this extinction there were many sorts of reptiles and amphibians on land, together with many plants, especially ferns but also conifers and gingkos. There were also complicated coral reef ecologies undersea. After the extinction, we mainly see fossils of one species of reptile on land: a medium-sized herbivore called Lystrosaurus. We also mainly see fossils of just one species of sea life, a brachiopod called Lingula. Eventually other species seem to reappear... clearly they were there before, but in very low numbers.

  This was the largest disaster that life has ever yet faced on our planet: perhaps 90% or even 95% of all species went extinct! It took about 50 million years for life on land to fully recover its biodiversity, with the rise of many species of dinosaurs. Nothing resembling a coral reef shows up until 10 million years after the Permian extinction, and full recovery of marine life took about 100 million years.

  The causes remain controversial: some scientists blame an asteroid impact, while others blame severe global warming and a depletion of oxygen in the atmosphere due to prolonged massive volcanic eruptions in Siberia - we see signs of these in lava beds called the "Siberian traps". On the other hand, Benton and others argue that the rise of carbon in the atmosphere at this time is only explicable if there was also a catastrophic release of methane from gas hydrates under the ocean.

  Never heard of "gas hydrates"? Hmm, they're interesting! Even today there is a huge amount of methane and other gases trapped in ice on the ocean floor! These so-called "gas hydrates" contain about 10,000 billion tons of carbon - twice as much as in all the fossil fuels on Earth. If this ever gets released in a giant "methane burp", we could be in trouble - this mechanism may have caused more than one drastic climate change. Some people have proposed mining this methane for fuel. But others have suggested stuffing carbon dioxide down there as a way to fight against the rise of greenhouse gases. This is called "sequestration" - and as you can see in my previous diary entry, the chairman of Shell thinks it's the only way to save the world from global warming.

  But I digress...

• The Triassic-Jurassic Extinction, 205 million years ago at the end of the Triassic Period.

  By the end of the Triassic there was again a variety of reptiles on land and in sea. But the reptiles were completely different from those at the end of the Permian, and the biodiversity had not completely recovered: for example, there were no truly large predators. There were primitive conifers and gingkos; ferns were not so dominant as before. There were also frogs, lizards, and even the first mammals.

  The extinction at the end of the Triassic destroyed 20% of all marine families, many reptiles, and the and the last of the large amphibians - opening niches for the dinosaurs of the Jurassic. The cause of this extinction remains obscure, but it's worth noting that around this time is when Pangaea split into separate continents, with massive floods of lava in the Central Atlantic Magmatic Province - perhaps one of the largest igneous events in the earth's history.

• The Cretaceous-Tertiary Extinction, 65 million years ago at end of the Cretaceous Period.

  By the Cretaceous there were dinosaurs and flowering plants on land, many new insects taking advantage of the flowering plants, and modern fish. In the disaster at the end of this period, perhaps about 50% of all species went extinct, including all the dinosaurs, many species of plants, diatoms, dinoflagellates, ammonoids, brachiopods, and fish. As explained above, it's widely accepted that this extinction was due to an asteroid impact at Chicxulub. It took 10 million years for biodiversity to recover from this event.

We're now seeing an intensification of the rate of extinctions as wilderness areas are obliterated throughout the planet. Nobody knows what the extinction rate is: since most species haven't even been catalogued yet, all we have are lower bounds. These are only close to being accurate for the biggest and most charismatic species (e.g. mammals, birds and trees), but these represent a tiny fraction of all the species that are out there. So, any reasonable guess of the extinction rate requires extrapolation.

Phillip and Donald Levin estimate that right now one species is going extinct every 20 minutes, and that half of bird and mammal species will be gone in 200 to 300 years. Richard Leakey estimates a loss of between 50,000 and 100,000 species a year, and says that only during the Big Five mass extinctions was the rate comparably high. E. O. Wilson gives a similar estimate. In his book, Michael Benton reviews the sources of uncertainty and makes an estimate of his own: given that there are probably somewhere between 20 and 100 million species in total, he estimates an extinction rate of between 5,000 and 25,000 species per year. This means between 14 and 70 species wiped out per day.

Skeptics find these numbers alarmist. For example, in Chapter 23 of this book:

• Bjørn Lomborg, The Skeptical Environmentalist: Measuring the Real State of the World, Cambridge U. Press, Cambridge, 2001.

In short, despite plenty of bickering, there seems to be agreement that humans are causing a vastly elevated extinction rate.

And there's also lots of other data pointing to a massive human-caused disruption of the biosphere. One in eight plant species are endangered according to the IUCN Red List of threatened species, along along with one in eight bird species and a quarter of all mammals. Worldwide populations of frogs and other amphibians have been declining drastically, and there has been a startling increase in the number of frogs with extra or missing legs and other deformities. The reasons are unclear, but one possible cause is increased ultraviolet radiation due to a reduction in the ozone layer. As you probably know, in 1985 scientists discovered a hole in the ozone layer over the South Pole, now known to be caused by human-made chemicals such as Freon. There is now also a 70% reduction in ozone over the North Pole during most winters.

In the oceans, 90% of all large fish have disappeared in the last half century, thanks to overfishing. We see the spread of dead zones near the mouths of rivers, where nutrients from fertilizer create blooms of plankton leading to low-oxygen water where few organisms can survive. Coral reefs are becoming unhealthy around the world, with a strong upswing in the bleaching of reefs since the 1970s. "Bleaching" is the loss of algae called zooxanthellae which live in coral and give it its color. It seems to be caused by higher water temperatures due to global warming.

And so on, and on, and on....

So, lots of evidence suggests that are in the midst of a mass extinction. But, it's very different than all previous ones. I don't think we can halt it; it's governed by seemingly unstoppable demographic and economic forces. Until the configuration of these forces shifts, at best we can only ameliorate their effects.

The good news is that's its unlikely to be worse than the Permian-Triassic extinction, so things may get better in 100 million years.

Some things I'd like to read:

• E. O. Wilson, The Diversity of Life, W. W. Norton and Company, New York, 1999.

• United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC), World Atlas of Biodiversity: Earth's Living Resources for the 21st Century, University of California Press, 2002.

• A. Hallam and P. B. Wignall, Mass Extinctions and Their Aftermath, Oxford University Press, Oxford, 1997.

As you can probably see from my last entry, I've been getting really interested in paleontology and the long view of history it provides. Since I'm travelling, I've been doing my reading mainly in the good book stores of Cambridge and London, but I mean to dig deeper when I get back to the university libarary at UCR. There's so much more known about this stuff than when I last checked! I'm just dying to get my paws on these, for example:

• S. Culver and P. Wilson, editors, Biotic Response to Global Change - the Last 145 Million Years, Cambridge University Press, Cambridge, 2000.

• J. J. Sepodski, Phanerozoic overview of mass extinctions, in Patterns and Processes in the History of Life, edited by D. Jablonski and D. M. Raup, Springer, Berlin, 1986.

• Rachel Wood, Reef Evolution, Oxford University Press, Oxford, 2000.

• Bjørn Lomborg, The Skeptical Environmentalist: Measuring the Real State of the World, Cambridge U. Press, Cambridge, 2001.

I figured I should read this book, because it's often touted by hardnosed business sorts as the scientific antidote to the doomsday scenarios of all those tree-hugging environmentalists - see my April 14 entry for an example. After all, the author says he was an "old left-wing Greenpeace member" who came to doubt these doomsday scenarios when, in his job as an academic statistician, he held a study group to investigate Julian Simon's claims that things were getting better, not worse... and found on that Simon was right! Just the sort of story that catches the attention of the press.

But if his book were just fluff, I wouldn't have bothered with it. It's actually packed with data, which makes it interesting, right or wrong.

The book consists of a bunch of chapters which seek to argue away most of the main worries environmentalists have. It would be fun to go through these one by one and try to make up my own mind. But I happen to be interested in biodiversity and extinction right now, so I focused on the chapter about that. I was interested to discover that in this case - and a few others, like global warming - he doesn't really deny there's a problem. He just disagrees about its magnitude and the proper response:

An extinction rate of .7 percent over the next 50 years is not trivial. It is a rate about 1,500 times higher than the natural background extinction. However, it is a much smaller figure than the typically advanced 10-100 percent over the next 50 years (equal to some 20,000 to 200,000 times the background rate). Moreover, to assess the long-term impact, we must ask ourselves whether it is likely that this extinction rate will continue for many hundreds of years (accumulating serious damage) or more likely will be alleviated as population grown decelerates and the developing world gets rich enough to afford to help the environment, reforest, and set aside parks.

There is a lot one could say about this! For example, one could ask why he speaks of an extinction of .7 percent of all species in the next 50 years, instead of 1,200 to 10,000 extinct species per year, even though the second is a logical consequence of the first and his estimate of the total number of species. Perhaps this is because he just got done ridiculing the enviromentalists for estimating an extinction rate of 40,000 species per year, and the difference between 40,000 and 10,000 doesn't sound as impressive as the difference between 40,000 and .7 percent? Or is it for a better reason, namely that most of our uncertainty in the total extinction number comes from our uncertainty in the total number of species, so a "percent of total species" figure is something we can get a better handle on?

Similarly, one could ask who is advancing a figure of "100 percent" for the extinction rate over the next 50 years. All life on earth dead? That seems a bit extreme.

But, it's very interesting to read his discussion of previous figures, some of which seem to have been simply pulled from a hat. It's also interesting to read the rebuttals in the magazine Grist, especially those by Norman Myers and E. O. Wilson, whose estimates were savaged by Lomborg. Amid all the polemics, there are references to what might be some very interesting data!

I hope to talk about this more soon. Unfortunately I have to go out now and be a tourist in London.

Okay, it's been fun wandering the docklands of London - in fact that the Museum in Docklands describing the development of London from Roman times up through the current housing boom makes an interesting economics lesson in itself! Though I'd heard about it in nursery rhymes as a kid and seen it in Arizona, I'd never realized the importance of London Bridge. It was built as a defense against Vikings: it kept them from sailing up the Thames. But for centuries thereafter, it gave Londoners control of all ship traffic into the heart of England... helping build this choke point into the grand city it is today!

But I want to talk about the controversy over the number of species that are going extinct, before I forget the details.

According to the skeptical environmentalist Bjøorn Lomborg, "the original estimate of 40,000 species lost every year came from Myers in 1979":

• Norman Myers, The Sinking Ark: A New Look at the Problem of Disappearing Species, Pergamon Press, Oxford, 1979.

Let us suppose that, as a consequence of this man-handling of natural environments, the final one-quarter of this century witnesses the elimination of 1 million species - a far from unlikely prospect. This would work out, during the course of 25 years, at an average extinction rate of 40,000 species per year, or rather over 100 a day.

This is Myers' argument in its entirety. If we assume that 1 million species will become extinct in 25 years, that makes 40,000 a year. A perfectly circular argument. If you assume 40,000, you get 40,0000. One naturally refuses to believe that this can be the only argument, but Myers' book provides no other references or argumentation.

The dramatic loss of biodiversity, expressed in the figure of 40,000 species a year, is a dramatic figure, created by models. It is a figure which with monotonous regularity has been repeated everywhere until in the end we all believed it. It has becomne part of environmental Litany. But it is also a figure which conflicts with both observation and careful modeling.

Bjørn Lomborg opens his chapter on biodiversity by citing my 1979 estimate of 40,000 species lost per year. He gets a lot of mileage out of that estimate throughout the chapter, although he does not cite any of my subsequent writings except for a single mention of a 1983 paper and a 1999 paper, neither of which deals much with extinction rates. Why doesn't he refer to the 80-plus papers I have published on biodiversity and mass extinction during the 20-year interim?

In this respect as well as others, Lomborg seems to be exceptionally selective. As my 1979 book emphasizes, the estimate of 40,000 extinctions per year was strictly a first-cut assessment, preliminary and exploratory, and advanced primarily to get the issue of extinction onto scientific and political agendas. If Lomborg had checked my many subsequent analyses (totaling one quarter of a million words) in the professional literature instead of taking me to task for providing "no other references or argumentation," he would have found more documented, modified, refined, and generally substantiated estimates.

Lomborg also takes a crack at E. O. Wilson:

Colvinaux admits in Scientific American that the rate is incalculable. Even so, E. O. Wilson attempts to put a lid on the problem with the weight of his authority: "Believe me, species become extinct. We're easily eliminating a hundred thousand a year." His figures are "absolutely undeniable" and based on "literally hundreds of anecdotal reports".

Before humans existed, the species extinction rate was (very roughly) one species per million species per year (0.0001 percent). Estimates for current species extinction rates range from 100 to 10,000 times that, but most hover close to 1,000 times prehuman levels (0.1 percent per year), with the rate projected to rise, and very likely sharply. To wit:

Based on the work of Stuart Pimm of Columbia University's Center for Environmental Research and Conservation, anywhere from one to several bird species go extinct annually out of 10,000 known species -- hence, say 0.01-0.03 percent of living bird species are extinguished per year. But birds are unusual in that threatened bird species receive an extraordinary amount of human intervention: The real figure of observed extinctions would be much higher, very likely 10 (0.1 percent) per year or more, were it not for heroic efforts to save species on the brink of extinction. Captive breeding, strict protection, and maintenance of reserves especially designed for bird and mammal species have many species hanging on that would otherwise have gone globally extinct in the past several decades. See, for example, the special treatment accorded the nine critically endangered but extant psittacids (parrots). If you look at non-bird species -- for example, terrestrial and freshwater mollusks, a relatively unprotected group -- the extinction rates are much higher.

The above consideration confirms the likely current extinction rate of 0.1 percent, 1,000 times greater than prehuman levels. That figure is also supported by the following indirect measures:

1. Area-species curves. Ecological research across a wide range of habitats shows that the number of species inhabiting a patch of land increases exponentially with the size of that patch. Different studies have produced different estimates for the species-area exponent; the higher the value of the exponent, the steeper the general relationship between land area and species diversity, so that a small change in land area has a large effect on diversity. In The Diversity of Life, I use the conservative values of the area-species exponent and rate of tropical deforestation to arrive at about 0.25 percent of tropical forest species extinguished or committed to early extinction annually. Since most species likely occur in tropical forests, these ecosystems are a good proxy: Even if no extinction occurred elsewhere, the planetary rate would still be 0.1 percent annually.

   What do we mean by "committed to early extinction?" Studies from tropical America, New Guinea, and Indonesia (cited in The Diversity of Life) show that when forest fragments are reduced to anywhere from one to 27 square kilometers, 10 to 50 percent of the species in the fragment go extinct within 100 years, consistent with the Diamond-Terborgh models of exponential decay. The area-dependent decline in mammal species of the U.S. and Canadian western national parks also accords with the picture of committed extinction by area reduction alone.

2. The velocity of passage of species through the categories in the World Conservation Union (IUCN) Red List of Threatened Species, from less endangered to extinct. This movement is also consistent with an extinction rate of 0.1 percent annually, at least for the best-known animal groups.

3. Population Viability Analyses. These studies assess the risk of extinction for individual small populations. Although not enough species have been studied this way to produce regional or global extinction rate estimates, the high risk evident in the populations that have been examined is consistent with a high ongoing extinction rate.

Andrew Nicolaysen recommends this book:

• James Buchan, Frozen Desire: The Meaning of Money, FSG, NY, 1997.

I wonder if you have seen the documentary "The Corporations", broadcast by TVO (TV Ontario). On their website they offer information about the program:

http://www.tvo.org/thecorporation/overview.html.

It is about the question: "If corporations are people, what kind of people are they?"

I haven't seen this documentary. It's by Mark Achbar, Jennifer Abbot and Joel Bakan. It sounds interesting, but I seem to have more time for reading things than watching shows - it's easier to efficiently grab ahold of the bits I want and skip the rest.

If you're interested in the operating system wars - Microsoft versus Apple versus Linux and others - you may enjoy this essay:

• Neil Stephenson, In the Beginning was the Command Line.

I was in Disney World recently, specifically the part of it called the Magic Kingdom, walking up Main Street USA. This is a perfect gingerbready Victorian small town that culminates in a Disney castle. It was very crowded; we shuffled rather than walked. Directly in front of me was a man with a camcorder. It was one of the new breed of camcorders where instead of peering through a viewfinder you gaze at a flat-panel color screen about the size of a playing card, which televises live coverage of whatever the camcorder is seeing. He was holding the appliance close to his face, so that it obstructed his view. Rather than go see a real small town for free, he had paid money to see a pretend one, and rather than see it with the naked eye he was watching it on television.

And rather than stay home and read a book, I was watching him.

Here's another wickedly charming sample of his wit:

The word, in the end, is the only system of encoding thoughts - the only medium - that is not fungible, that refuses to dissolve in the devouring torrent of electronic media. The richer tourists at Disney World wear t-shirts printed with the names of famous designers, because designs themselves can be bootlegged easily and with impunity. The only way to make clothing that cannot be legally bootlegged is to print copyrighted and trademarked words on it; once you have taken that step, the clothing itself doesn't really matter, and so a t-shirt is as good as anything else. T-shirts with expensive words on them are now the insignia of the upper class. T-shirts with cheap words, or no words at all, are for the commoners.

• Naomi Klein, No Logo: Taking Aim at the Brand Bullies, HarperCollins, 2000.

On September 25, Leon Kuunders recommended a documentry about how pathological corporations would seem if they were people. It turns out that this documentary is based on a book, and he has kindly offered to get me a copy:

• Joel Bakan, The Corporation: The Pathological Pursuit of Profit and Power, Free Press, 2004.

It may seem eccentric to judge corporations by the standards we judge people, but it's actually a useful exercise.

Why?

First of all, we must remember that at least in the US, corporations are persons in the eyes of the law. Technically, they're "artificial persons". This has been the case ever since the 1886 Supreme Court ruling in Santa Clara County v. Southern Pacific Railroad. In a clear case of judicial activism if there ever was one, this ruling redefined the concept of "person" to include corporations. In fact, it did so without hearing any arguments on this question, or providing any reason. The details are pretty interesting! According to David Korten:

In 1886 [...] in the case of Santa Clara County v. Southern Pacific Railroad Company, the U.S. Supreme Court decided that a private corporation is a person and entitled to the legal rights and protections the Constitutions affords to any person. Because the Constitution makes no mention of corporations, it is a fairly clear case of the Court's taking it upon itself to rewrite the Constitution.

Far more remarkable, however, is that the doctrine of corporate personhood, which subsequently became a cornerstone of corporate law, was introduced into this 1886 decision without argument. According to the official case record, Supreme Court Justice Morrison Remick Waite simply pronounced before the beginning of argument in the case of Santa Clara County v. Southern Pacific Railroad Company that:

The court does not wish to hear argument on the question whether the provision in the Fourteenth Amendment to the Constitution, which forbids a State to deny to any person within its jurisdiction the equal protection of the laws, applies to these corporations. We are all of opinion that it does.

The court reporter duly entered into the summary record of the Court's findings that:

The defendant Corporations are persons within the intent of the clause in Section 1 of the Fourteenth Amendment to the Constitution of the United States, which forbids a State to deny to any person within its jurisdiction the equal protection of the laws.

[....]

The doctrine of corporate personhood creates an interesting legal contradiction. The corporation is owned by its shareholders and is therefore their property. If it is also a legal person, then it is a person owned by others and thus exists in a condition of slavery - a status explicitly forbidden by the Thirteenth Amendment to the Constitution. So is a corporation a person illegally held in servitude by its shareholders? Or is it a person who enjoys the rights of personhood that take precedence over the presumed ownership rights of its shareholders? So far as I have been able to determine, this contradiction has not been directly addressed by the courts.

• David C. Korten, The Post-Corporate World: Life After Capitalism, Berrett-Koehler Publishers, 2000.

Self-centered welfare: A person's welfare depends only on her own consumption and other features of the richness of her life (without any sympathy or antipathy towards others, and without any procedural concern).

Self-welfare goal: A person's only goal is to maximize her own welfare.

Self-good choice: A person's choices must be based entirely on the pursuit of her own goals.

Which persons do you know that act like this? Answer: corporations!

So, we see an interesting parallel development: the legal system redefining "person" to include corporations, while economists redefine the concept of rationality in such a way that corporations more closely resemble the ideal rational person than actual people do!

I don't think this is the result of some sort of "conspiracy": some bunch of economists and judges in a smoke-filled room scheming to let corporations take over the world. It actually seems like a natural form of evolution. Governments naturally set up the rules to favor powerful political entities. During the last century or two, corporations have become the most powerful political entities. As part of this process, the discipline of classical economics arose to describe homo economicus. In other words, it describes human behavior modeled on how a good businessman - or by extension, a well-functioning corporation - would behave. Conversely, people working for corporations imbibe classical economics in school, and this influences how they behave. Eventually this economic paradigm gets applied to government itself and the feedback loop is complete.

So, we have feedback pushing us towards a world in which corporations are the main actors - legally recognized as persons - and ideally they behave as classical economic theory says rational agents should. By this, I mean:

• their utility depends only on their own profits, revenues, market share, etc. -
  without any sympathy or antipathy towards others, and without any procedural concern,

• their goal is to maximize their own utility,

• they make choices based solely on this goal.

Of course, as composite entities, corporations actually behave in a much more complicated manner, determined by the decisions of all their constituents. E.g., the president of corporation X may make decisions based on the fact that he hates the president of corporation Y; the clerk has no qualms about stealing ballpoint pens from the office; the board of directors gives the president of corporation Z a big pay raise because he's done the same for them in his role on the boards of corporations they run. The above is just a kind of ideal.

But, even as an ideal, it's shockingly different from the ideals espoused by various other philosophies of human life!

(By the way, I'm curious about whether corporations are counted as "persons" in all the world's legal systems, and the history of this issue.)

A bit of news:

Under a new "temporary rule" issued by Bush administration, the Forest Service will no longer need to maintain viable populations of fish and wildlife in national forests - suspending a policy instituted by the Reagan administration in 1982, in response to the National Forest Management Act of 1976. President Reagan approved regulations that require:

1. the Forest Service to maintain viable populations of species in national forests; and
2. that those populations of species be well-distributed throughout the natural forests in which they are present.

I'm getting interested in finding out the rate at which the world's oil reserves will get used up. Like the rate of extinction of species, this is an incredibly controversial topic, in part because it's hard to figure out the answer, but also because there are big ideological pressures both ways for people to bend the truth.

Here's one viewpoint:

• Colin J. Campbell, Peak Oil, Presentation at the Technische Universität Clausthal, December 2000.

• Association for the Study of Peak Oil and Gas (ASPO) website.

Here's some fascinating reportage of one of their recent meetings:

• Michael C. Ruppert, Paris Peak Oil Conference Reveals Deepening Crisis.

But before I get into this dispute, I should try to wrap up my conclusions about extinctions thus far!

• Simon N. Stuart, Janice S. Chanson, Neil A. Cox, Bruce E. Young, Ana S. L. Rodrigues, Debra L. Fischman, and Robert W. Waller, Status and trends of amphibian declines and extinctions worldwide, Science, published online October 14 2004.

The findings are grim. Of 5743 known amphibian species, 34 have gone extinct, while 122 can no longer be found and are considered "possibly extinct". Even worse, of the 122 possibly extinct species, 113 disappeared after 1980!

This means that 0.6% of amphibian species have certainly gone extinct in the last century, while another 2.1% are probably extinct. Moreover, about 32.6% are either extinct or threatened, while 22.5% are too poorly documented to assess.

You may recall that the "skeptical environmentalist" Bjørn Lomborg estimated a 0.7% extinction rate in the next 50 years. Amphibians may be especially vulnerable to acid rain, increased ultraviolet light and other forms of human-caused environmental degradation - nobody knows for sure what's afflicting them - but it looks like their extinction rate over the next 50 years will exceed Lomborg's estimates by at least an order of magnitude, and probably more.

Amphibians have been around a long time. They arose in the Carboniferous Period about 350 million years ago, weathered the world's biggest mass extinction at the end of the Permian Period 251 million years ago, attained their current forms around 150 million years ago, and survived the downfall of the dinosaurs 65 million years ago. In the words of David Wake of U.C. Berkeley's museum of vertebrate zoology, "the fact that this tough survival group is checking out on our watch should concern us all".

For more details on how this data was collected, try the Audubon website.

Here are some interesting charts they released:

• Temperature in Greenland over the last 100,000 years.

• Temperature in the Arctic over the last 100 years.

• Greenland Ice Sheet - Melting as of 1992 versus 2002.

I think these speak for themselves: things are warming up near the North Pole. Of course, we've been in a strange cold spell with intermittent ice ages for roughly the last 1.8 million years - the Pleistocene Epoch. The thin sliver of recent time since the latest ice age called the Holocene Epoch, but this is an arbitrary division geologically speaking, distinguished only by the rise of humans. If we hadn't come along, it seems quite possible that there would be more ice ages until the Earth returned to its normal warmer climate. Our production of greenhouse gases might just be pushing us back to this normal climate more rapidly. But I use the word "just" ironically here: if this return to warmer conditions happens suddenly - over a few hundred years, say - such a drastic change would have an incredible impact on humans and other species. Animals and especially plants take a long time to move north or south and "resettle" as the climate changes; too sudden a change and they just die out.

Switching focus to the South Pole, an article in Nature reports that the amount of krill in the southwest Atlantic has fallen by about 80 percent since 1979:

• Angus Atkinson, Volker Siegel, Evgeny Pakhmonov and Peter Rothery, Long-term decline in krill stock and increase in salps within the Southern Ocean, Nature 432 (November 4, 2004), 100-103.

Krill are small crustaceans that look a bit like shrimp to the untrained eye. Krill are a crucial link in the food chain: before their recent decline, their biomass exceeded 1 billion tons! Fish, seals, whales, penguins and other birds in the southern Atlantic all eat krill, so an 80% drop in krill would be major blow to the entire ecosystem.

Why such a drastic decline in krill? Atkinson's best guess is global warming. There's been a drop of at least 30 days in how long the sea ice lasts near the Antarctic Peninsula - the main breeding ground for krill. Krill eat algae that grow on sea ice. The average air temperature at the Antarctic Peninsula has gone up by 2.5 degrees Celsius in the last 50 years.

Even more worrisome is that these days, not every winter is cold enough for a good krill breeding season - only every third year or so. Krill live for 5 to 6 years. If the gap between good breeding years reaches 6 years, their numbers will really plummet.

There are extra complications. Krill are a "boom and bust" species whose population changes erratically, so Atkinson needed to average the data over a long period to reliably detect a long-term trend. Steve Nicol of the Australian Antarctic Division questions whether the krill population could really have declined so much without their predators dying off at a corresponding rate - and he claims that's not happening. He says that krill may have moved deeper now that the ozone hole over the Antarctic is making for more ultraviolet light... or that rebounding whale populations are feasting on the buggers. "Something's happened," he says. "We're just not quite sure what".

This is hard to do, because if you look at the history of the universe, it seems like everything is speeding up, approaching a "singularity" a bit like the big bang, but in reverse - and with humanity doing all the interesting stuff, instead of gravity and elementary particles. The term "singularity" is probably not very accurate; I think "phase transition" is a better metaphor. But, if you've never thought about this before, you have to read stuff by Vernor Vinge, who brought this idea into prominence under the name "The Singularity":

• Vernor Vinge, What is the singularity?

• Wikipedia, The technological singularity.

• Robin Hanson, ed., A critical discussion of Vinge's singularity concept.

As Vinge points out, it goes back at least to John von Neumann. In his 1958 recollections of von Neumann, his friend Stanislaw Ulam wrote:

One conversation centered on the ever accelerating progress of technology and changes in the mode of human life, which gives the appearance of approaching some essential singularity in the history of the race beyond which human affairs, as we know them, could not continue.

But, to have any chance of understanding this singularity, or phase transition, I think we need to situate it in the large frame of geological time. This is especially true when it comes to the effects of humanity on the biosphere, such as climate change and mass extinction. We can only hope to comprehend these by comparing them to events in the distant past... and viewing them from a perspective where a century passes in the blink of an eye.

This idea isn't new to me, of course: some people are popularizing it under the name of "Deep Time", while others call it "The Long Now". It's really just part of growing up....

I've been reading various books and also this nice website.

• Manchester Metropolitan University, Global Climate Change Student Guide.

The short answer is: nobody knows why it got cold.

Since "why" is too hard, how about "what" and "when"?

Let's start our story at the beginning of the Cenozoic Era. The Cenozoic - the age of mammals - began with a bang around 65 million years ago when an asteroid smacked into Mexico and the dinosaurs died out. The Cenozoic is divided as follows:

• Paleogene: 65 - 24 million years ago.
  • Paleocene Epoch: 65 - 55 million years ago.
  • Eocene Epoch: 55 - 34 million years ago.
  • Oligocene Epoch: 34 - 24 million years ago.

• Neogene: 24 - 0 million years ago.
  • Miocene Epoch: 24 - 5.3 million years ago.
  • Pliocene Epoch: 5.3 - 1.8 million years ago.
  • Pleistocene Epoch: 1.8 - .01 million years ago.
  • Holocene Epoch: .01 - 0 million years ago.

The scheme above still suffers from this defect: the Pliocene is much shorter than the Miocene, the Pleistocene is shorter still, and the Holocene Epoch started a mere 10,000 years ago - a pathetically thin slice of time from a geological perspective. It includes everything after the last ice age, which is presumably only the "last" in the weak sense that the next one hasn't happened yet! As far as geology and climate goes, we're still in the Pleistocene Epoch: an epoch of many ice ages. The current gap between ice ages only gets a special name because we, humans, started seriously acting up at this time! Of course, we may cause enough global warming to truly end the Pleistocene, in which case we'll deserve our own epoch even by geological standards.

Anyway...

Though the beginning of the Cenozoic was cooler than the maximum temperatures of the Paleozoic, it was much warmer than today. Oxygen isotope ratios show the ocean was 10° to 15° Celsius warmer than today. For Americans who know nothing of metric units, that's 18-27 degrees Fahrenheit. That's hot!  There were trees growing in Antarctica then, no permanent polar ice caps.

The temperature began to drop as soon as the Cenozoic started. By the Oligocene, 34-24 million years ago, glaciers started forming in Antarctica. The growth of ice sheets led to a dropping of the sea level. Tropical jungles gave ground to cooler woodlands.

What caused this? Some seek the answers in plate tectonics. The Oligocene is when India collided with Asia, throwing up the Himalayas and the vast Tibetan plateau. Some argue this led to a significant change in global weather patterns. But this is also the time when the supercontinent Gondwanaland finally broke up, with Australia and South America separating from Antarctica. Some argue that the formation of an ocean completely surrounding Antarctica led to the cooling weather patterns. There are issues of timing involved here... how do we explain the general cooling pattern starting at the beginning of the Cenozoic?

The beginning of the Miocene, 24 million years ago, is when the first grasses arose. It's sort of amazing that something we take so much for granted - grass - can be so new! But grasslands, as opposed to thicker forests and jungles, are characteristic of cooler climates. And as Nigel Calder has suggested, grasslands were crucial to the development of humans! We grew up on the border between forests and grasslands. That has a lot to do with why we stand on our hind legs and have hands rather than paws. Later, the agricultural revolution relied heavily on grasses like wheat, rice, corn, sorghum, rye, and millet. As we ate more of these plants, we bred them in a way that completely changed their characteristics. So, you could say we coevolved with grasses!

Indeed, the sequence of developments leading to humans came shortly after the first grasses. Apes split off from monkeys 21 million years ago, in the Miocene. The genus Homo  split off from other apes like gorillas and chimpanzees 5 million years ago, near the beginning of the Pliocene. The fully bipedal Home erectus  dates back to 1.9 million years ago, near the end of the Pliocene.

Then, at the beginning of the Pleistocene, 1.8 million years ago, the Earth entered an even cooler phase, with jerky temperature variations causing a series of ice ages. Experts call them "glacials".

The latest of these ended around 16 thousand years ago, with temperatures reaching their present levels only around 10 thousand years ago. We can see this from oxygen isotopes in ice from Greenland, and we can see it from the rise of sea levels.

As we get closer to the present the data gets more accurate and we can spot small fluctuations on top of larger trends - this is one reason it feels that things are happening faster. Though things have basically been warming up in the last 16 thousand years, there was a severe cold spell between 12 and 11 thousand years ago: the Younger Dryas event.

(I love that name! Was there also an "Elder Dryas"? If you're interested, you can read more about it here.)

The Younger Dryas lasted about 1300 years. Temperatures dropped dramatically in Europe: about 7°C in only 20 years! In Greenland, it was 15° C colder during the Younger Dryas than today. In England, the average annual temperature was -5° C, so glaciers started forming. We can see evidence of this event from oxygen isotope records and many other things. One favored explanation is that the melting of the ice sheet on North America lowered the salinity of North Atlantic waters. This in turn blocked a current called the Conveyor Belt, which normally brings warm water up the coast of Europe. So, ironically, global warming may have brought on a sudden deep freeze in this region.

But, this theory is quite controversial - see my October 11, 2006 diary entry for an update!

Anyway, the Younger Dryas ended as suddenly at it began, with temperatures jumping 7° C. Since then, the Earth continued warming up until about 6 thousand years ago - the mid-Holocene thermal maximum. The earth was about 1 or 2 degrees Celsius warmer than today. Since then, it's basically been cooling off - not counting various smaller variations.

But as we zoom in towards the present, we see more and more tiny details....

From 6000 to 2500 years ago things cooled down, with the coolest stretch occuring between 4000 and 2500 years ago: the Iron Age neoglaciation.

Then things warmed up for a while, and then they cooled down from 500 to 1000 AD. Yes, the so-called "Dark Ages" were also chilly!

After this came the Medieval climate optimum, a period from about 1000 to 1300 AD during which European temperatures reached their warmest levels for the last 4000 years.

From 1450 AD to 1890 there was a period of cooling, often called the Little Ice Age. This killed off the Icelandic colonies in Greenland, as described in this gripping book:

• Jane Smiley, The Greenlanders, Ballantine Books, New York, 1996.

Since then, things have been warming up. The subject has big political implications, and is thus subject to enormous controversy. But, I think it's safe to say this warming is much greater  than the other variations I've mentioned over the last 1000 years. For example, this chart:

• Millenial Northern Hemisphere temperature reconstruction, adapted from Mann, Bradley and Hughes by the Intergovernmental Panel on Climate Change for their report Climate Change 2001: The Scientific Basis.

Of course, this ain't much compared to the 15-20 Celsius cooling throughout the Cenozoic - but it's happening fast, and it's not over yet!

Addendum: I was intrigued and puzzled by the name "Younger Dryas" until Nicola Ambrosetti emailed me this:

I came across something that reminded me of you: in case you never found out, here's where the name "Younger Dryas" comes from - see the Dryas Octopetala article on Wikipedia:

The Younger Dryas and Elder Dryas stadials are named after Dryas octopetala, because of the great quantities of its pollen found in cores dating from those times. During these cold spells, Dryas octopetala was much more widely distributed than it is today, as large parts of the northern hemisphere that are now covered by forests were replaced in the cold periods by tundra.

So apparently there is also an Elder Dryas period!

Best regards,
Nicola

As you know, the Kyoto Protocol is an attempt to reduce greenhouse gas emissions and lessen global warming. Russia has recently signed on, but the political leadership of the United States has rejected this treaty because of its effects on the economy: since the USA is one of the biggest users of fossil fuels per capita, cutting back on greenhouse gases would "hurt the economy", as they like to say.

Of course, to tell whether this treaty would really hurt the economy, one needs to do a cost-benefit analysis. This is incredibly complicated, and I'm in no position to do it here. There are a bunch of issues involved which make it a highly controversial business.

I'll gladly avoid some of these controversies. For example, in the United States, the "full ostrich position" is popular: global warming is not real; it's just a figment of the imagination of some nuts obsessed with the environment. There are also a variety of half ostrich positions, where you stick your head in the sand but keep one eye out to avoid looking really stupid. For example: global warming is real but not human-caused. Or: it's real, and more research needs to be done to see if it's human-caused, but we shouldn't pay for this research, and in the meantime we should subsidize the sale of gas-guzzling SUVs and open the Arctic wilderness for drilling. The latter seems to be the current position of the Bush administration.

I don't even want to bother arguing against these positions - I have better things to do with my time, like debate physics with crackpots who send me their crazed theories and bet that I can't disprove them.

A more interesting point is made by the "skeptical environmentalist" Bjørn Lomborg. He admits that global warming is real and caused by humans, and admits it will have negative effects that will outweigh the benefits. Indeed, he estimates the total cost at $5 trillion (with costs discounted at a certain unspecified rate per annum). But, he says that the cost of completely preventing global warming would be so outrageous that it's not worth it - and adds quite correctly that the Kyoto Protocol, at least by itself, would not limit greenhouse gases enough to make big difference on global warming.

His full position is fairly complex. To summarize with a few quotes:

Global warming is important. Its total costs could be about $5 trillion. Yet, our choices in dealing with global warming are also important, with few, carefully chosen actions shaving some hundred billion dollars off the global warming price but with many actions which could cose the world trillions and even tens of trillions over and above the global warming cost.

[....]

To give a feel for the size of the problem - the Kyoto Protocol will likely cost at least $150 billion a year, and possibly much more. UNICEF estimates that just $70-$80 billion a year could give all Third World inhabitants access to the basics like health, education, water and sanitation.

[....]

In Figure 166 we see the total income over the coming century for the four main scenarios in the IPCC (Intergovernmental Panel on Climate Change). If we chose a world focused on economic development within a global setting, the total income will be some $900 trillion. However, should we go down a path focusing on the environment, even if we stay within a global setting, humanity will lose some $107 trillion, or 12 percent of the total, poetntial income. And should we choose a more regional approach to solving the problems of the twenty-first century, we would stand to lose $140-$274 trillion or even more than a quarter of the potential income. Moreover, the loss will mainly be to the detriment of the developing countries [....]

Again, this should be seen in the light of a total cost of global warming at about $5 trillion and a cost of all other environmental policies throughout the twenty-first century of $18 trillion. What this illustrates is that if we want to leave a planet with the most possibilities for our descendants, in both the developing and the developed world, it is imperative that we focus primarily on the economy and solving our problems in a global context rather than focusing - in IPCC lingo - on the environment in a regionalized conext. Basically, this puts the spotlight on securing economic growth, especially in the third world, while ensuring a global economy, both tasts of which the wolrd has set itself within the framework of the World Trade Organization (WTO). If we succeed here, we could increase world income with $107-$274 trillion, whereas even if we achieve the absolutely most efficient global warming poliices, we can increase wealth just $0.245 trillion (Figure 164). To put it squarely, what matters to our and our children's future is not primarily decided within the IPCC framework but within the WTO framework.

Yet, one could be tempted to suggest that we are actually so rich that we can afford both to pay a partial insurance premium against global warming (at 2-4 percent of GDP), and to help the developing world (a further 2 percent), because doing so would only offset growth by 2-3 years. And that is true. I am still not convinced that there is any point in spending 2-4 percent on a pretty insignificant insurance policity, when we and our descendants could benefit far more from the same investment placed elsewhere. But it is correct that we are actually wealthy enough to do so.

• William Nordhaus and Joseph Boyer, Roll the DICE Again: Economics Models of Global Warming, MIT Press, Cambridge, Massachusetts, 2000.

but it's mainly based on estimates of the cost to agriculture, forestry, fisheries, the changing cost of energy production, water supply, and infrastructure, the cost of hurricanes, drought, coast protection, land loss, and the loss of wetlands, forests, animal and plant life, and human life.

But,  this doesn't take into account lower-probability but higher-damage scenarios like a repeat of the Younger Dryas event!

I talked about the Younger Dryas in my last entry. About 11,000 years ago, global warming caused a meltdown of the glaciers in North America. The resulting vast flow of fresh water into the North Atlantic disrupted a worldwide current pattern called the Great Ocean Conveyor, or more prosaically, the "thermohaline circulation". It's this current that makes Europe warmer than you'd otherwise expect. So when it quit, temperatures plummeted by 7 °C. And this happened fast - in a matter of a mere 20 years!  The average temperature in England dropped to -5° C, and glaciers started forming!

See:

• David Suzuki Foundation, The Great Ocean Conveyor: the Achilles heel of the climate system?

• Terrence Joyce, Abrupt Climate Change: Are We on the Brink of a Little Ice Age?, Woods Hole Oceanographic Institution.

• Abrupt Climate Change: Inevitable Surprises, National Academies Press, 2002.

Warm waters are carried north by the Gulf Stream, cooling as they travel. By the time they reach the vicinities of Labrador and Iceland, these waters have grown cold and dense. During winter the coldest, saltiest waters sink thousands of metres below the surface to form North Atlantic Deep Water (NADW). The heat released to the atmosphere during NADW formation is largely responsible for the relatively warm temperatures enjoyed by western Europe.

If not for the North Atlantic loop of the Conveyor, European winters would be much colder. Berlin might have the climate of Edmonton, which lies at the same latitude, while Stockholm might be more like Iqaluit.

This is what it was like during Younger Dryas. It lasted for about a thousand years. Then, when the ice in North America was more or less done melting, the Great Conveyor started up again - and in 20 years the temperature popped back up!

So, climate change is not always gradual. And another event like this could be on its way now! To quote the second website listed above:

Consider first some observations of oceanic change over the modern instrumental record going back 40 years. During this time interval, we have observed a rise in mean global temperature. Because of its large heat capacity, the ocean has registered small but significant changes in temperature. The largest temperature increases are in the near surface waters, but warming has been measurable to depths as great as 3000 meters in the North Atlantic. Superimposed on this long-term increase are interannual and decadal changes that often obscure these trends, causing regional variability and cooling in some regions, and warming in others.

In addition, recent evidence shows that the high latitude oceans have freshened while the subtropics and tropics have become saltier. These possible changes in the hydrological cycle have not been limited to the North Atlantic, but have been seen in all major oceans. Yet it is the North Atlantic where these changes can act to disrupt the overturning circulation and cause a rapid climate transition.

A 3-4 meter, high latitude buildup of fresh water over this time period has decreased water column salinities throughout the subpolar North Atlantic as deep as 2000m. At the same time, subtropical and northern tropical salinities have increased.

The degree to which the two effects balance out in terms of fresh water is important for climate change. If the net effect is a lowering of salinity, then fresh water must have been added from other sources: river runoff, melting of multi-year arctic ice, or glaciers. A flooding of the northern Atlantic with fresh water from these various sources has the potential to reduce or even disrupt the overturning circulation.

Whether or not the latter will happen is the nexus of the problem, and one that is hard to predict with confidence. At present we do not even have a system in place for monitoring the overturning circulation.

In short, the view from Deep Time suggests that we are messing with things we don't understand - and the stakes could be high. We can try to learn more, and we can try to be careful in the meantime... or we can just go ahead and see what happens.

Messing with things we don't understand is nothing new: it's what humanity has always done. In fact, it's how evolution has always proceeded: organisms try stuff and take the consequences! Sometimes they win, sometimes they lose. Any one species always loses eventually. If we use our intelligence constructively, we might last longer.

I was reading your latest entry in your economics diary. Here's what George Monbiot has to say about Lomborg's arguments:

The idea that we can attach a single, meaningful figure to the costs incurred by global warming is laughable. Climate change is a non-linear process, whose likely impacts cannot be totted up like the expenses for a works outing to the seaside. Even those outcomes we can predict are impossible to cost. We now know, for example, that the Himalayan glaciers which feed the Ganges, the Bramaputra, the Mekong, the Yangtze and the other great Asian rivers are likely to disappear within 40 years. [15] If these rivers dry up during the irrigation season, then the rice production which currently feeds over one third of humanity collapses, and the world goes into net food deficit. If Lomborg believes he can put a price on that, he has plainly spent too much of his life with his calculator and not enough with human beings. But people listen to this nonsense because the alternative is to accept what no one wants to believe.

The quotation is at the end of this article:

• George Monbiot, Goodbye, Kind World, The Guardian, August 10, 2004.

Reference 15, about Asian rivers drying up, is to:

• Glacier meltdown, New Scientist, 182 issue 2446 (8th May 2004).

• Anil V. Kulkarni, B. P. Rathore and Suja Alex, Monitoring of glacial mass balance in the Baspa basin using accumulation area ratio method, Current Science 86 (10th January 2004) 185-190.

Reading a Scientific American article on abrupt climate change, I found some interesting references:

• Peter Schwartz and Doug Randall, An abrupt climate change scenario and its implications for the United States national security.

• Michael Vellinga and Richard A. Wood, Global climatic impacts of a collapse of the Atlantic thermohaline circulation, in Climate Change  54 (2002), 251-267.

• Spencer Weart, Rapid climate change, in The Discovery of Global Warming, Harvard U. Press, Cambridge, 2003.

• Richard A. Wood, Michael Vellinga and Robert Thorpe, Global warming and thermohaline circulation stability, Phil. Trans. Roy. Soc. Lond.  A 361 (2003), 1961-1975.

For my 2005 economics diary, go here.

© 2004 John Baez
baez@math.removethis.ucr.andthis.edu

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