Climate Change or Climate Forcing...redux

kw: musings, greenhouse effect, greenhouse warming, global warming, climate change, climatology, analysis

When I wrote a book review on the subject of climate change a few days ago, I had something in mind, but the review went in a different direction. The title actually didn't fit any more. Here are charts I made to illustrate my thinking on the terminology about "carbon pollution" and all the hype surrounding it, on both sides. Firstly, an nGram of the usage of three popular terms since 1970:

Although warming caused by the greenhouse effect, in particular that caused by carbon dioxide, was quantified by Svante Arrhenius in 1896, only after about 1970 was it brought to public attention. The great promotion of this issue really took off after 1985. This nGram shows that, in print at least, "Greenhouse Effect" was soon superseded by "Climate Change" and "Global Warning". But let's focus on a different term and its scientific synonym:

You can see from the upper chart that the term "Climate Forcing" has been scarcely a blip on the radar. But on the scale of the lower chart we see that about the time "Greenhouse Effect" peaked, "Climate Forcing" began to surge (relatively speaking), and shortly after that, "Anthropogenic Climate Change", a more scientific synonym, came along, but it is quite a mouthful.

It is a pity that Google stopped scanning books in 2008. I'd like to see how these words have fared in these past ten years. Nonetheless, I did a Google search for all these terms and a few others I've thought of in the past day or two (put in quotes to force literal searching), setting the search time to the past year, here is how they score:

• 7 - Anthropogenic Climate (allows "change" or other following words): 488,000
• 8 - Anthropogenic Climate Change: 478,000
• 6 - Carbon Pollution: 523,000
• 1 - Climate Change: 147,000,000
• 9 - Climate Forcing: 366,000
• 4 - Climate Science: 2,310,000
• 5 - Climate Warming: 975,000
• 2 - Global Warming: 56,600,000
• 3 - Greenhouse Effect: 4,360,000
• 10 - Greenhouse Warming: 295,000

The number preceding each term is its rank in this alphabetized list.

Why do people use the words they use? Impact. "Climate Change" and "Global Warming" get the public's attention. But the actual debate is not really about whether climate is changing or the globe (i.e. its atmosphere) is warming. It is about the extent that human civilization contributes to the change or the warming. However, "Anthropo..whatever" is too much of a mouthful, and "Climate Forcing" doesn't have quite the ring of the more popular terms.

But: Climate Forcing is really the best term about which to have a policy debate. The atmospheric climate will change gradually over time, whether the human race is highly civilized or goes extinct. Prior to 1975, the big worry about "Climate Change" was about "Global Cooling". A cooling trend highlighted by the first 15-18 years of weather satellite measurements triggered fears of a new ice age. And we find that the recent Solar Maximum had lower sunspot activity than most prior cycles. Based on historical records, this could indicate a cooling trend because lower solar activity heats the Earth's atmosphere less than average. Sunspot numbers are an indicator (not a cause) of the number of flares and other phenomena that send extra energy our way.

So, how big a factor is Climate Forcing? Let's call the Climate Forcing Factor the CFF. The way the media report things, one group called "climate deniers" would say the CFF is close to zero. In the same media, a group called "established science" claims the CFF is "most" or "nearly all" of the difference, in the range 50%-90%. Putting aside my conviction that the media are rather incredibly biased, we can instead identify the poles of the debate as "Large CFF" and "Small CFF" factions. Who is right? Do we have a way to know?

We don't, actually! But we can dig out an indication or two.

This article in ScienceDirect states that variations in sunspot activity account for about 40% of long term temperature rise in Norway over the past century, with a probable range of 25-56%. For a different portion of the North Atlantic, the range is 63-72%. This ought to please the Large CFF folks.

Remember the ozone hole? Starting about 30 years ago colleagues of mine at DuPont determined the great amount of damage being caused to the ozone layer some 15 miles (~25 km) overhead, and this triggered research efforts at DuPont and other chemical companies to find new refrigerants for air conditioners and new propellants for aerosol cans. The ozone "hole" was a dramatic thinning of this layer mainly over Antarctica, but spreading halfway to the equator, and there was a similar, but smaller thinning over the Arctic. But we need to be clear: the "ozone layer" isn't pure ozone; it is where ozone is concentrated to a level of about one part in 100,000 (0.001%); it is still mostly nitrogen. Ozone at sea level is around 1/30th of this, about 1/3,000,000th. Chlorine from refrigerants and propellants in use before 1980 had reduced the level of ozone over the poles by about 2/3, and elsewhere by about 20%. "Ozone hole" is the dramatic term that refers to the reduction of ozone from 1/100,000 to 1/300,000 over Antarctica during the southern summer.

Ozone is funny stuff. It is created from oxygen by ultraviolet light (UV), and then it absorbs UV, which heats it up. So the more ozone, the more the atmosphere is heated from the top. Specifically, at subtropical latitudes, surface temperature averages about 300K (27°C or 81°F), while 15 km (9½ mi) above, air temperature has fallen to about 200K (-73°C or -100°F). Ozone and other stratospheric gases absorb UV and some IR to raise the temperature back to 300K by about 50 km (30 mi) altitude. This warm gas in the mid- to upper stratosphere emits thermal radiation (longwave infrared) both upwards and downwards, which heats the air below a little. The gradual increase in stratospheric ozone levels over the past 30 years have contributed a little heating, but I have not found a rigorous analysis of the matter. "About a degree" is a general statement I have read. This is a factor that tends to please the Small CFF folks.

These things indicate that the CFF is unlikely to be greater than 50%, and is probably closer to 25% or less. I would not say, "close to zero", so I am not in the extreme Small CFF crowd, but neither do I favor Large CFF. As I have stated elsewhere, I learned that if we were to raise carbon dioxide levels to, say, ten times their present level, the amount of greenhouse heating would not exceed 4°C or about 7°F. That is quite significant. Is it enough to end civilization? I don't think so, but it will definitely change it. We are unlikely to find out, though. If we were to burn all the fossil fuels that we currently know about, it would no more than double the amount of carbon dioxide that we have already emitted. That's another way of saying that we have already burned about half the global reserve of fossil fuels. In rough terms, it means we have so far doubled atmospheric carbon dioxide, from around 200 ppm to around 400 ppm. Once we run out of natural gas, oil and coal—should we continue freely burning them—the level could become around 600 ppm. I don't think we have enough fossil fuel available to push that to 1,000 ppm, where some people begin to feel the effects.

For all that, we must continue to find other sources of energy, on all fronts. No source of energy is perfect. Wind farms (currently 4% of global electricity generation) disturb wind patterns, heat the air that passes through the fan blades, and kill migrating birds; solar panels turn about 15-20% of sunlight into solar energy and the rest is turned into heat, and much of this would be in desert areas where the sand usually reflects 75% of the light right back out into space; geothermal energy is "clean" from a heat perspective, because the heat will emerge from the earth anyway, but using geothermal energy causes pollution of surface water and ground water, a whole lot of pollution; and so forth. The more we learn about all these things, the better we can select energy generation methods that cause the least harm. That, and that alone, will reduce the CFF. It will probably never be zero, until human population is zero.

Postscript: Do you know what the global average temperature is? I am a geophysicist. Including the whole planet, the average temperature is about 4,000K (over 7,000°F). We need a different term for "global average atmospheric temperature", and we need to always specify at what elevation; is it surface, or at the average elevation of continental plains (about half or 2/3 a kilometer), or some other "standard" height?

Climate change or climate forcing?

kw: book reviews, nonfiction, astronomy, astrobiology, exoplanets, climatology, climate change, global warming

Do we need to save the planet? It doesn't need it. Do we need to save the biosphere? We don't yet have the power to end it. Do we need to save civilization? Probably. This last is the question taken up by Adam Frank in Light of the Stars: Alien Worlds and the Fate of the Earth. He takes a new approach, you could say a Galactic approach, even a Universal approach, to setting parameters around the future of human civilization.

Dr. Frank uses a quieter tone than the noisy polemicists in the toils of public debate. He is nonetheless speaking as a prophet, warning us all of the consequences of the greatest of human endeavors, "the project of civilization." I found it notable that he never mentions the IPCC Reports. This is not to say that he doesn't give them any credence, but he is preaching to the unconverted: I learned long ago, in Christian evangelism, it does no good to quote Bible verses to someone who doesn't believe the Bible. Similarly, the content and methods behind the IPCC's work are challenged at every point by "climate deniers", so it is no use appealing to those reports.

In this book the author begins with Carl Sagan's metaphor of Western civilization as a teenager, grown up in body but not in judgement. Here in the US at least, we give 15- or 16-year-olds licenses, and the keys, to drive automobiles, knowing full well that their minds won't mature, and they will have very poor impulse control, for at least ten more years. So, at the very least, we in the First World are like a teenager with the keys to the energy sources of Planet Earth, and we have shown an utterly insatiable appetite for more and more energy use. This chart is instructive:

This shows energy use per person (credit: Our Finite World). The technology to mine and use coal jump-started the nascent Industrial Revolution in about 1850. Petroleum and Natural Gas triggered a further jump beginning right after World War I, which was stalled by the Depression, and then re-invigorated by World War II. The "flat spot" from about 1970-2000 is the effect of the Arab Oil Embargo. I suspect the development of Fracking to rejuvenate oil production in non-Arab nations is responsible for the jump after 2000.

So now we use four times as much energy per person as someone in 1820. That is a global average. Per-person use in the First World is in the 250-300 GJ/yr range, or 3-4 times the global average. So that is our "car". It has a lot of horsepower.

The question Sagan asked, based on figures from the 1960's, is, "Can the Earth provide the needs of human civilization, forever?" To abolish poverty worldwide, we'd need to roughly triple global resource use, particularly energy use. But we are seeing "cracks in the wall" already. Someone once said, to raise the entire population to the American level would require four more Earths.

What is Adam Frank's line of analysis? He continues with the Drake Equation, formulated in 1961,
that uses several factors to estimate the number of alien civilizations we might find using efforts such as SETI, the Search for Extra-Terrestrial Intelligence, which uses radio frequency reception, in hopes of overhearing the alien version of "I Love Lucy". He dissects this for us and then presents the uses of a method developed by Svante Arrhenius, 122 years ago, to determine how much the earth will warm based on how much extra carbon dioxide gets into the atmosphere. "Climate science" is not new stuff, folks!

The Arrhenius method doesn't just work on Earth. It was used to understand what happened to Venus, to raise its temperature to 600°F, and why Mars is a bit warmer than it would be without any atmosphere, though daytime highs in its "Tropics" range around -10°F. Mars and Venus both have an atmosphere containing 95% carbon dioxide. Venus has a very, very heavy atmosphere while the air on Mars is very thin, about 1% of Earth-normal. But our air contains, at present, 400 ppm CO₂, or 0.04%. Martian air with enough nitrogen added to have the density of Earthly air would still have 0.95% CO₂, nearly 24 times as much! So the temperature range on, for example, airless Phobos, compared to that on Mars, validates the Arrhenius analysis for a CO₂-induced greenhouse effect (yes, Phobos is colder).

After presenting the history of exoplanet discoveries—a few thousand are now known—the author turns the Drake Equation on its head, to determine the "Pessimism Line". That is his term for how pessimistic you need to be to say we are surely alone in the Universe: Knowing that the stars in all the galaxies range in age up to 10+ billion years, and that there are about 100 billion stars in each of 100 billion galaxies (or perhaps even more) in the visible Universe, how pessimistic do you have to be to strongly aver that our Human civilization is the first and (so far) only civilization to have arisen in the Universe?

In 1961 the only factor of 7 in the Drake Equation that was known was the rate of star formation in the Milky Way Galaxy, about one per year. All the other terms were speculative, and all possible values of, for example, the chance that a planet will be at a "just right" distance from its star (in the habitable zone), were strongly supported by various people. You could find someone who'd argue that the probability was close to zero; someone else who'd argue that any star that had planets probably had at least one in the habitable zone. Now, with a few thousand known exoplanets, we know that nearly every star has multiple planets, and about 40% of those have at least one planet in the habitable zone. So the unknown terms are:

• Can life form easily, or not?
• Once formed, can life develop "intelligent" species easily, or is it very hard?
• Is the likelihood that an intelligent species will form a global civilization large, or small? and 
• Once formed, how long will such a civilization continue?

By turning all this around backwards, the combination of these "biological" and "sociological" terms needed to make it very unlikely that more than one civilization has ever been formed, was found to be 10^-22. That is one in ten billion trillion. This is a quantitative estimate of how hostile the Universe must be to civilization, for us to be alone in all space and time (to date). Effectively, this analysis presents you with a pile of sand, a trillion tons of it, containing ten billion trillion grains, and asks, "Knowing that at least one sand grain represents a civilization in the Universe, how likely is it that no other grain of sand represents a planet with a civilization? Not one single one?"

For most of us, the thought that civilization arose only once in ten billion trillion attempts is rather ludicrous. Even Peter Ward with his Rare Earth analysis, is probably not that pessimistic!

Dr. Frank then goes further, asking, "What does it take for a civilization to be sustainable, very long-term?" Numerous isolated and semi-isolated civilizations on Earth have risen and fallen. It seems even Earth, so hospitable to life of many kinds, can he hostile to civilizations…or, at least, unforgiving of egregious errors. Further, civilizations that fell, did so quickly. The environmental disasters, caused by the Easter Islanders and the Mayans all doing what people do to have a thriving society, reduced populations to about one tenth of what had once been in just one or two generations. Even today, there are fewer Mayans than there were in 1200 AD. These are two examples of civilizations that fell not because of conquest by someone else, but at their own hand. Two cases of a teenager driving right off a cliff.

The book closes with an appeal to wake up and grow up. It would be well to heed it. To my understanding, no civilization yet produced on Earth has figured out the trick to sustaining itself without perpetual growth. In the US, a growing GDP is required for a "robust" economy. The US government recently announced a 4.1% annual growth rate (that really means 0.335% growth for that particular month). It is good in a way. But if it keeps up, we can project it into the future: In just 17 years, GDP would double, and it would keep doubling again every 17 years. By 2100 AD the US GDB would be 27 times what it is today. What chance is there of that happening? Hmmm??

Suppose we finally get the analysis right, and find out that, for human civilization on Earth to be sustainable for 100, or 1,000, or 10,000 years, we would have to reduce our population to at most two billion, and the general lifestyle and level of energy expenditure (both personal and corporate) would need to match that of Peru (about ¼ of what us Americans are used to)? Then what? I'll tell you what: whatever the actual level of lifestyle really is, in time the biosphere will enforce it.

We are not divorced from Earth. We cannot act as though we were not part of nature. Nature can get along without us. We cannot get along without nature. Civilization is an experiment. It may be one that eventually fails. The Pessimism Line only tells us how unlikely it is that we are on the only planet to develop civilizations. It doesn't tell us how long they last. That part of the Drake Equation is still entirely unknown.

I would put it this way: If there is any chance for a global civilization to develop and thrive, and properly care for all its members, without constant growth in both population and standard of living, we need to figure that out right away. Or we, too, will crash, just a bigger version of the Mayans or Easter Island.

The double whammy of a hot climate

kw: musings, climatology, tropics

In the former post I reviewed Under a Green Sky by Peter D. Ward. He makes a distressing point or two about living on a tropical planet.

The human species evolved primarily during ice ages, particularly the 100,000 years since "anatomically modern" humans arose. The tropics (the 30% of Earth's surface between 23°S and 23°N) were more temperate than now, perhaps by 8-10°C (14-18°F). Dr. Ward writes

"We who live in the more comfortable climes seem to think that just because the human tribes who lave long inhabited the equatorial zone have evolved through many generations living in constant heat, night and day, that somehow these people no longer feel the heat and humidity, that unlike us, they are not made uncomfortable by the horrible climate. Not so."

Maybe we've all read or heard of people in the tropics who seem able to work in the heat without sweating much. It is never stated that they have a secret. Nearly everyone who lives in the tropics without air conditioning uses one or another of the legal drugs so abundantly supplied in tropical plants.

Remember, most plants are trying to avoid being eaten by herbivores and omnivores. Woodiness helps; even many leaves (such as elm—ever chewed one?) are woody and unpalatable. Grasses and sedges incorporate silica crystals in their tissues to make them harder to chew. But most plants use chemical defenses, hence their bitter taste. The taste isn't just a sensory deterrent, it usually indicates the plant is poisonous.

Some plant poisons that kill or weaken insects and other small animals don't harm people nearly as easily. The common substance Caffeine is an insecticide, and deters some small mammals, but office workers worldwide consume a half gram or more daily "just to keep going." By chewing coffee beans and camellia leaves (tea leaves), people for centuries used Caffeine as a stimulant and mild analgesic...it really does help you cope with heat.

Caffeine is just about the only "heat helper" that doesn't hinder mental acuity. Around the world people use Kava (Polynesia), Betel (Indochina), Marijuana (almost anywhere, often used with one of the others), Khat (India to East Africa & Turkey), and Coca plus Cacao and Coffee (South America).

With or without drugs that can numb the mind, tropical heat is so enervating that one cannot sustain critical thinking. It is well known that few great mental achievements arose in the tropics. This is not because the people living there are less smart, but that the climate makes them work extra hard to have any thoughts at all.

I've worked with people who were born in hot places, now living in temperate America. They are formidably intelligent, whether from Uganda, Colombia, or Vietnam. But now we're coming to a subject covered in more detail by another book I'll review soon. Just a point from issues that overlap that book and this one:

Drop a typical urban or suburban Westerner into the Congo, New Guinea, or the Amazon, with an overnight bag and a knife. Set up a betting pool on when he or she will die. It'll be a matter of days. Now drop a typical native of the Congo, New Guinea, or the Amazon into New York City, London, or Paris, with an overnight bag and a knife. His or her grandchildren are likely to own the building your grandchildren work in. So who is smarter?

Global warming means bad winters

kw: book reviews, science fiction, global warming, climatology, near-future, alternate history, trilogies

I read Kim Stanley Robinson's Forty Signs of Rain a few years ago, before beginning these reviews. The second book in the trilogy, Fifty Degrees Below, came out about a year ago, and Sixty Days and Counting is due out in a half year (Spring 2007).

Fifty Degrees Below continues Frank's assignment at NSF, working with Director Diane Chang. Frequently, the book goes on as a pure continuation of its forerunner, so much so that one can get a little lost if reading it without having read the other. A trilogy author has to balance the needs of readers who first encounter a sequel against those familiar with earlier work. I know too much explaining the "obvious" can get annoying to one's more faithful readers, but annoying new readers is also risky.

There are two stories here. The private story of Frank's love life is woven into a realistic portrayal of a major expected effect of polar warming: shutdown of the Gulf Stream. This portrait is well-researched and well-presented. It ought to be required reading by all policy makers, particularly those (sadly, mostly 'conservatives' who are bent on anything but conservation) who deny human-caused (or at least human-emphasized) warming.

Frank comes across as a neo-cave man. As the novel opens, he must move out of a borrowed apartment, and recent severe flooding in the DC area has driven housing costs very high. He winds up living in a "distributed" home: his office, the back of his van, a tree shelter, and a health club. A flood-damaged park near the National Zoo is his backyard. He hangs with homeless guys and begins running with a small band of compulsive Ultimate Frisbee players. They are portrayed like a neolithic hunting party in their camaraderie...rather apropos, I'd say.

The book ends with a massive effort to re-start the Gulf Stream with a half million tons of salt, and with Frank's love interest in hiding from her "blacker than black" spook of an ex-husband.

A subtext is electronic surveillance via "chips", poppy-seed-size microwave transponders, the offspring of the RFID chips retailers want to put in clothing (eventually all goods). A little physics knowledge is the spoiler here: The most efficient wavelength a single-wire antenna can transmit is four times its length. A millimeter-size chip, unless it's attached to a longer wire, works best at a 4-mm wavelength, or a frequency of 75 Ghz. Even at this resonant frequency, the received (and thus echoed) signal strength is proportional to the square of the antenna length, so you just can't get much of a signal into or out of such a little chip, even at its best frequency.

Passive RFID (no battery) works by bathing the chip in pulses of strong microwaves at its resonant frequency; the chip is briefly powered by each pulse to respond with a serial number modulating that frequency. So, some of the energy runs the little processor that encodes the number, and most of the rest can get re-emitted.

I'm a radio ham, and have fooled around with microwaves. RFID works pretty well at frequencies in the 1-3 Ghz range. Such devices require a 1- to 3-inch (25 to 75 mm) antenna. You only lose about half the energy if you coil the antenna up, as long as it is still the size of a dime, more or less. However, remember that the energy capture, and thus that available for re-radiation, drops as the square of the length of the antenna.

Inch-size chips work at ranges of a few inches, less than a foot even with a 3-inch straight antenna, unless you whack them with a large microwave pulse, large enough for someone to feel. Then their "echo" can be detected a few meters away. You need an expensive sniffer that can send a big pulse, then turn on a very sensitive receiver in a nanosecond or less to receive the return signal. Go from 75mm to 3mm in wavelength, and the signal drops by a factor of 625. You can receive it from a few meters away only if you have a meter-size dish pointed exactly at the little chip!

The rice-grain-size passive chips people now put in their dogs work at a range of about six inches. You have to sweep the reader over the dog's back at least that close. You're not going to drive down the street and pick up an echo from your dog's chip. Although I expect technology to improve a lot, I suspect chips cannot get any smaller than a sesame seed, and still be detected by a doorway-mounted device as you step through.

The use of tiny chips does lend a frisson of drama to the narrative. I just wish the author had thought, you don't need to destroy chips or even shed them to avoid detection. If you know a chip is in your sweater, just wrap your sweater in foil and drop it into a carry bag. The dark gray bags made of conductive plastic, that many electronic components come in, are ideal "chip shields." If someone should implant a chip in your arm, you can hide by wearing any long-sleeved shirt with a lot of metallic threads woven in. These aren't popular now, but I expect them to resurge...

There is a lovely scene in the book, a regatta at the North Pole. The sun is depicted as standing still in the sky on midsummer's day. Actually, it'll circle the sky at an elevation of 23 degrees. I wonder how many readers will catch that one.

However, pardon my quibbles; the book is a great read, and on a subject with which I have much sympathy. I'm awaiting Sixty Days and Counting.

The Weather: 56; Human Race: 0

kw: book reviews, nonfiction, weather, climatology, history, world events

A kiloton of TNT, the basic unit of nuclear explosion energy, is just over a million kilowatt-hours (1.16x10⁶ KWH). The Megaton, about the energy of the smallest thermonuclear bomb, is a thousand kilotons, or about a billion KWH. These factors allow us to compare large amounts of solar and wind energy with the largest energies we are capable of directly wielding.

The atmosphere weighs about 11.6 quintillion pounds, or 5¼ quintillion kg. This mass is kept in motion by a small amount of the solar energy that strikes Earth, at a speed that averages a few meters per second. The earth intercepts 172 trillion KW of solar energy, mostly in the tropics and subtropics. Some fraction of this drives the atmosphere, and a (very roughly) similar fraction evaporates water from the oceans into the air. Condensation of water back out of the air drives those focused thermal energy systems we call storms, from summer showers to tornadoes and hurricanes.

Water vapor condensing to rainfall in a category 1 hurricane releases heat energy of about 14 trillion KWH per day. Divide that by the billion or so KWH in a kiloton bomb, and we see the energy equivalent of thousands of H-bombs, daily, in an "ordinary" hurricane. It took all the members of the Nuclear Club about sixty years to stockpile enough bombs to equal about two days' energy release by a "small" hurricane.

So where am I going with this? I just read Blame it on the Rain: How the Weather Has Changed History by Laura Lee. The book consists of 56 stories, in essay form, of the weather having a strong impact on human events. (Before I go further, I should mention that the stories we hear of a "nuclear winter" being caused by a nuclear war are overdone. We don't get a "hurricane winter" each time one of these storms roars through a tropical sea or pummells a coastline. Nor when a similarly-sized winter supercell (rarer, but just as energetic) covers the middle third of a continent and drops something like four feet of snow over a half million square miles. Such a supercell, a thousand miles wide, shut down all the airports from Oklahoma City to Chicago about thirty years ago...Winter ended on schedule anyway. And by the way, none of the numbers above are in the book. It's just my musings to get this essay rolling...)

One point of Ms Lee's book is that all human plans and powers need to take the powers of nature into account, or we are the losers. Among the essays are the four-part saga of various belligerent nations trying to defeat Russia, which is always well defended by "General January". Less well known is the spring mud that follows, the "rasputitsa". This "coroner" buries the dead the General kills...and most of the survivors as well.

Other stories include fog hiding armies, rain delaying battles until crucial reinforcements arrive, and winds helping or hindering, seemingly at random, our various schemes. One ill-timed wind gust ensured that the Wright brothers' first flight was not scooped by Langley. An extra-strong El Niño did away with Robert Scott in Antarctica, while aiding Amundsen's team to the first South Pole visit.

Mark Twain (or a co-author) wrote, "Everybody talks about the weather, but nobody does anything about it." We're a long way from doing so. So-called "weather modification" is typically "weather irritation", and the storm in questions tends to act like a flea-bit dog and scratch back. In 1972, west of Rapid City, SD, a small airplane flew up the front of a gathering storm and "seeded" it with silver iodide. This storm stopped in its tracks, blasted through to the stratosphere, and dumped a foot of rain into Rapid Valley, just below a flood-control dam. A quarter of Rapid City was washed downstream. This isn't in the book, either; most of the stories are about political and military events.

So don't go around singing "Don't rain on my parade." The weather just might take you up on it.

That old Climate may be pretty nimble...

kw: book reviews, climatology, history, anthropology

One of my brothers, a Mayan archaeologist, was interviewed for the Discovery Channel a couple years ago. He told of the destruction of the forest around Palenque because the Mayans used huge quantities of charcoal to make stucco. All their buildings are plastered with several inches of stucco, perhaps as insulation.

Among more than a hundred theories about the destruction of the Mayan civilization some 1100 years ago, regional drying and crop failures are a prominent part of many. Regional or global climate shifts have been proposed only recently.

Among the many factors one may list, we must take account of a major dry period in all of Mesoamerica from about 750 AD to about 950 AD. Civilizations are defined by their mass effort to mitigate the effects of bad periods. They stave off droughts and other disasters, even ones that may last a few years, as the U.S. survived—though with much suffering—the dust bowl years of the 1930s, and as Joseph's Egypt was able to survive a 7-year famine around 1900 BC (with divine forewarning).

No civilization has survived a 200-year drought, though the Mayans came close: the Mayan collapse occurred in three phases beginning in 760 (about ten years into the drought) and ending about 910. Had they hung in there for another generation or two, they'd be a major civilization today.

The details needed to pin down such stories are found in abundance in The Winds of Change: Climate, Weather, and the Destruction of Civilizations by Eugene Linden. Note carefully, the word "Civilizations". This book does not forecast "the destruction of civilization", but reports on the destruction of a number of civilizations in the past, and points out the environmental and climatological influences that coincide with them. While one coincidence does not imply causality, many coincidences of the same type make a strong case.

Author Linden presents his material as a case, with opening arguments, presentation of evidence, cross-examination and rebuttal, and closing arguments. This format leads to some rather dry reading. Fortunately, much of the book is well and stirringly written, and he makes a good case.

It is a puzzle that, as an increasing majority of scientists agree that climate can change rapidly and violently, has done so in the past, and appears to be on the verge of doing so in our lifetimes, public and media complacency—even denial—are at an all-time high. To most people, "long term planning" means at most five years. Most retirement advisers work with a horizon of thirty to forty years. Futurists, even my favorite, Bruce Sterling, write about the next fifty years with great frequency, scarcely about longer periods. Few folks can think in terms of something global in scope and multi-generation in effect. We need stories with more immediacy.

So, I really like these articles about poison ivy: Global warming may aid poison ivy and CBC News: Poison ivy itchier when carbon dioxide levels increase. Even if we freeze CO₂ production at current levels, the atmospheric content will rise from the current level of about 370 ppm (0.037%) to 570 ppm (0.057%) by 2050. At that level, poison ivy in an experimental forest with extra CO₂ gas in the air was found to grow 150% faster each year, compared to plants grown without the extra CO₂, and they contained 150% more urushiol, of a more toxic variety.

Let's work this out: 150% faster means for each pound of poison ivy in Forest A, Forest B produces 2.5 pounds; 150% more urushiol means each pound of leaves contains 2.5 times as much of the stuff. Put it together, and Forest B has 2.5x2.5 = 6.25 times as much urushiol production per acre! And the icing on the cake? Urushiol is a mix of oils of varying toxicity. Forest B urushiol has a larger proportion of the worst oils.

In Japan, this might be considered a good thing, because they use urushiol to make the lacquer for lacquerware (the lacquer isn't toxic), and to paint all those lovely temples and palaces. For the rest of us, forest burning anywhere will create six times as much toxic smoke. My wife has caught bad rashes from dried leaf bits blowing around. More CO₂ means an itchier future. That hits home with me more than an extra meter of ocean water.

"The Winds of Change" sounds an alert. The author is not being alarmist. He is frustrated at our case of galloping apathy. Perhaps, to paraphrase Ronald Reagan, to keep a car that is getting bogged down off one side of the road from falling further, it is necessary to plant oneself firmly on the other side with a tow truck, and pull HARD.

It is now known to everyone who cares to look, that past climate changes have been abrupt and violent. The "Little Ice Age" of the 14^th-18^th Centuries was less violent than most, yet it caused widespread misery, appalling death rates, indirectly fostered staggering epidemics, and changed Western society permanently...another century and the Renaissance would have died aborning. Dare we neglect signs that the climate is about to make a major switch?