by fire and ice and ...

The Life and Death of Planet Earth
By Peter Ward and Donald Brownlee
Henry Holt/Times Books, 2002
RATING: **1/2 (of 5)

How many ways can the Earth end?

Probably more than anyone with anything less than a (slight) obsession with the concept is willing to consider.

Just so happens, I guess I have such an obsession, at times anyway. So do Ward and Brownlee, who spend over 200 pages exploring just about every possible doom the Earth will eventually face over the next 6-8 billion years.

Before I get into analyzing what they say, I'll give a quick timeline as they see it (not quoted from them, but culled from various places in their book. The quotebox layout is simply for display. All dates, obviously, are estimates.):

Next few centuries: Global warming sparked in part by human actions.
2-10 MY: Ice Age resumes, with periods of warming just like last million-plus years.
100 MY: Continents begin to re-coalesce into a new Pangaea.
250 MY: New Pangaea firmly established, with extremely arid interior and stagnant oceans, sparking large-scale extinctions.
500 MY - 1 BY: Solar warming moves habitable zone beyond Earth's orbit.
500-700 MY: Plant photosynthesis ends as CO2 levels gradually fall below 10 ppm, with periods of oscillating plant expansion and dieoff; growing heat causes life to retreat to poles.
approx. 15 MY after that: Atmospheric O2 levels have fallen to about 1% of present, extinguishing what's left of animal life. Beyond 60 deg. C, only bacteria, algae and some fungi survive.
1 -1.2 BY: global mean temp. is about 70 deg. C. Oceans begin evaporating, causing the "moist greenhouse effect" that features brutal storms. Plate tectonics comes to a halt from lack of water, eventually resulting in a global ocean. Last bacteria fry around 235 deg. F. @
2.5 - 3.5 BY: "Runaway greenhouse effect" takes over at about 200 deg. C, after all water is gone. Earth becomes like Venus.
3 - 4 BY: Andromeda Galaxy (M31) merges with Milky Way. Gravity and other forces might sling solar system into deep space, or might not.
6 - 7 BY: Sun expands to giant size, possibly reaching Earth orbit. Solar effects cause Moon to swirl back to collision with Earth & possibly cause Earth to spiral into Sun. If not, Earth ends up scorched cinder orbiting white dwarf after Sun goes nova.

Whew. Anything I left out?

Oh, yeah, the "accidental armageddon" causing events -- huge comets or asteroids (it took one about 10 km across to cause the K/T extinction 65 MY ago, and would take one about 100 km across to sterilize all life) or supernovae in the galactic neighborhood (think Sirius; when it goes, its gamma rays will have some serious effect on everything within about 30 light years. We're 12 LY away).

This catalog makes nuclear war look like a game...

Now, I can't realistically refute most of what they say; it seems pretty plausible that, essentially, Earth's life path from here on will retrace its path of the last 4.5 BY, as they propose. But I do take issue with some of their assertions within the various future periods.

First off, obviously, is the near future. There, they allege that the combination of global warming and subsequent ice age return will cause survivors to be "starving" even "thousands of years forward." I strongly doubt that; human gene-lines flexible enough to survive the coming few centuries will have adapted to the new conditions and created or found new food sources. Yes, the short-term will probably see extensive starvation as our ability to fuel modern agriculture runs dry (assuming we don't get our collective head out of our ass very soon and change gears completely), but the population will eventually decline to a stable level. I suspect we'll still have agriculture in some places, maybe even cities, but having people recall what the Space Needle or global warming is (p.71) after a few thousand years is nonsense.

The resumption of ice age doesn't mean civilization has to vanish, although there's little doubt large swaths of the planet will be inhabitable only by the most intrepid folks, as in Antartica today. I could see people having outposts on the ice caps, even towns if we have the foresight to plan technology for that purpose. I'm not the first to think of this, BTW; Michael Kube-McDowell envisioned the Weichsel people with whole cities on the ice, and even an ice-based construction technology, in his novel Empery.

It will, however, mean major changes. Most humans will have no choice but to retreat toward the equator and change how, where, and maybe even what we farm, but I think we're capable of that. Earth will be a drier place, but we've lived through such times before. We can do it the same way we did it then -- by having very dispersed paleolithic-sized (or maybe medieval) populations or by taking the genuinely global outlook that is today struggling to be born and nurturing it. The former would be a likely consequence of nations feuding over dwindling resources; the latter is the only way to face our future and still retain those elements of civilization that are actually beneficial. Not all of them are.

What we do and which elements we keep may determine how long humanity survives as a species, because events AFTER the ice age are likely to be far less hospitable, if Ward and Brownlee are right.

As they note, "we must either take steps to sustain the habitability of our own world or find another at a younger stage of planetary life. ...If we can't engineer or evolve our way around our planet's inevitable decline, then we'd better go planet shopping." (21-22).

The former is, is the sense of planetary time, a band-aid approach -- it's necessary if WE want to stay alive over the short-term, but won't have much effect on life's overall path; only planet-hopping can keep us alive indefinitely, if that's even possible or desirable. In general, I think it is, at least for the next several millennia; as I've said elsewhere, it's necessary if we want to evolve AND maintain civilization. The neo-paleolithic option above will allow for evolution, but not civilization.

If finding other living worlds proves to be effectively impossible, survival will require us to change our attitude to one that sees our talents as being in the service of Earth-life as a whole -- a change we really need to make anyway, since other Earths won't be accessible for a long time.

This outlook flies in the face of a thread that pops up occasionally in this book. On several occasions, Ward & Brownlee express a clearly biased view of other lifeforms. For example, they note "human-level intelligence and technology would never develop on a water-covered planet. There would be neither the need nor the opportunity" (31) -- How would they know? This assertion might be true of technology, but not necessarily true of intelligence; they admit whales and dolphins have "large brains and some level of sophisticated communication," but aren't willing to acknowledge that much of our complexity is cultural, not due to basic intelligence. We have the advantage of being FIRST, but not (hopefully) the only Earthlife to become technological; I strongly suspect we can help other species to do at least some of what we've done.

Elsewhere, they attribute the fact that our current climate "norm is not normal" (79) to long-term causes -- a 70 MY greenhouse gas cycle, orbital cycles#, and continental drift (specifically, the creation of a land bridge between North and South America). While all are indeed factors, they never mention a factor that at least needs to be considered because it's far more timely -- agriculture. Starting just after the Wisconsin/Wurm glaciers receded, people made major changes to the tree cover around the world in an accelerating manner. Apparently, the use of fossil fuels for 150 yrs or so will have a long-term climate effect more profound than 10,000 yrs of slash-and-burn agriculture? That may be true, but evidence would be far better than simply asserting it as fact.

Speaking of evidence, their attribution of sources seems very unprofessional. Yes, they have a pretty lengthy bibliography, but have almost NO references within their text: No footnotes (except to some photos), no direct quotes, and few references to other scientists by name. In several places, I found comments that were clearly referring to something they'd read, but there's no way to actually find out what that was without reading EVERY bibliography source. In some cases, I've seen sources that contradict them (for example, they assert that Ice Age America included "huge deserts and sand dunes" (74), but an Oak Ridge Nat'l Lab map I've seen says only one pocket of America was sandy desert then), and I'd love to see their source. Same's true of their core point that earth's biological fecundity peaked around 300 MY ago and is now slowly declining; Science Daily says the oceans experienced a huge peak 4-6 MY ago.

While I understand they're writing for a popular audience, that's not an excuse for inaccuracy and dumbing down the text. They have a lot of material to work with and the thesis makes sense, but the inaccuracy, occasional redundancy, and spots of arrogance only weaken their ideas.

________________

@ -- This figure is how they wrote it (it stood out as one of two Fahrenheit references, p. 143, amid all of the other Celsius and metric references. I'm not sure if they meant F or C, but there is a significant difference between them.) For scientists, their phrasing is woefully imprecise in other places, too. On p. 34, they write, "Earth's proportion of water to its weight is small ... less than one-tenth of one percent." Weight means nothing in science; the term is mass, and that figure is accurate, but WAY off -- the actual figure is 1/50 of a percent (.023%), if I'm calculating the figures here properly. Saying that is similar to saying "Earth's population is less than 30 billion" -- true, but it gives an extremely distorted impression of the facts.

# -- There are three orbital cycles -- of 95,000, 41,000, and 22,000 yrs. Regarding the first of these, they contradict themselves. On p. 80, they say we're currently at a position where Earth's orbit is closest to the Sun in January and farthest in July, meaning that "summer [sic] snows may last longer than the long-term norm." On p. 82, they note that a previous interglacial (i.e. WARM period) was at a time when "orbital eccentricity was at a minimum" and "just such a pattern of minimal orbital eccentricity is underway now." Huh?!? Only one of those assertions can be correct. For more info, see the Naval Observatory's orbital cycles page.

"The Big Chill"

TV show; The Science Channel
June 2005
Issue: Climate change

Lots has been said about the global warming vs. next ice age debate. What this show points out, as other sources are beginning to, is that warming may cause an ice age, and possibly quickly.

To understand why that is, I need to briefly summarize a little oceanography for you (if you don't already know):

Normally, the Gulf Stream carries warm tropical water from the coast of South America north along the US coast, then across to northern Europe before losing enough heat to sink to the bottom of the Atlantic in the Barents Sea. At the bottom, it returns to the tropics to repeat the cycle. That's known as the Great Conveyor Belt, or, in technical terms, "thermohaline circulation."

But, as the globe warms, higher than normal quantities of meltwater from high-latitude glaciers and rainwater from rivers flows into the Atlantic and, being fresh water, it's lighter than the salty ocean. It dilutes the Gulf Stream at its northern end and prevents the water from sinking, causing the Conveyor belt to stop running, or at least to drop to the bottom at some more southerly point.

The Conveyor is the primary reason northern Europe is inhabitable at all. As one speaker on the show noted, it carries about "one million power stations" worth of heat to a part of the world that's at a latitude where Canada has polar bears and Siberia gets winter temps of -40 C on a regular basis. Look at a world map -- or, better yet, a night-time photo -- and you see a striking difference between Europe and other places at the same latitude: Europe is a beehive of cities, home to nearly 500 million people, while the rest of that strip of Earth (except eastern North America)is almost vacant by comparison. (I know the photo seems fairly bright, but a lot of the brightness in western Canada and Siberia is not from cities, it's from oil fields burning off natural gas.)

Right now, annual temperatures are rising, but how much is still debatable; climatologists predict a change of 1.5 to 6 C by 2100, and governments worldwide are to some degree planning for the effects of that heat. But, if this branch of research is accurate, the warmth will be temporary, followed in short order by a rapid cooldown that could last centuries.

Scientists have been finding that Barents Sea salinity is dropping, causing "the largest and most dramatic oceanic change ever measured in the era of modern instruments," according to the US Woods Hole Oceanographic Institute, which led the research. London's Independent newspaper, from which the above quote was taken, says this would cause "a nightmare scenario where farmland turns to tundra and winter temperatures drop below -20C" in Britain. The paper reports (link added):

When the Gulf Stream abruptly turned off about 12,700 years ago, it brought about a 1,300-year cold period, known as the Younger Dryas. This froze Britain in continuous permafrost, drove summer temperatures down to 10C and winter ones to -20C, and brought icebergs as far south as Portugal. Europe could not sustain anything like its present population. Droughts struck across the globe, including in Asia, Africa and the American west, as the disruption of the Gulf Stream affected currents worldwide.

Now, it seems really counter-intuitive to assume heat causes freezing, and that's where research by Thomas F. Stocker comes in (emphasis added):

He and colleague Andreas Schmittner looked at the problem through experiments with a simple, coupled atmosphere-ocean climate model in which a final carbon dioxide concentration of 750 ppm was attained over different time spans. They found that the thermohaline circulation weakens when the increase in carbon dioxide to 750 ppm is relatively slow, spanning several centuries or more. However, when the rate of increase in atmospheric greenhouse gases (expressed as CO2) is similar to today's rate of growth (1% per year)--or the concentration of 750 ppm is reached in 100 years--the thermohaline circulation permanently shuts down.

Hmmm... It permanently shuts down. That's not too encouraging, is it? I suspect he means for the foreseeable future, centuries or millennia, not for the rest of Earth's lifespan, but that's a detail that would make no difference as far as humans go.

Despite the fact that the Bush II administration seems to be ignoring, even demonizing, climate research, the US Defense Department shows some signs of taking it seriously. (Of course... this admin focuses everything on military issues, rather than all the other effects such a problem could have...) In a report by Peter Schwartz & Doug Randall, they found that, "With inadequate preparation, the result could be a significant drop in the human carrying capacity of the Earth's environment."

Schwartz & Randall admit their scenario, which is based on the events that caused a century of cooling 8200 years ago (and thus would NOT be as severe as an ice age), is "not the most likely, but (is) plausible." Overall, they predict, such a cooling could spark wars over food and water supplies and severely restricted energy availability due to frozen ports and increased storminess. "Unlikely alliances could be formed as defense priorities shift and the goal is resources for survival rather than religion, ideology, or national honor."

While reviewing the history, they note that at least eight sudden temperature drops have occurred over the past 730,000 years, and note that a drop like one of the most recent, the Younger Dryas (c. 12.700 yrs ago) or the Little Ice Age (CE 1300-1850), would have a much more serious effect on humans now than then because of our much greater population and, I'd add, the fact that so many people are not living off the land directly.

Their model falls between the two in severity, but still predicts "mega-droughts" in parts of Europe and Asia and less severe droughts in America and elsewhere that "overwhelm available (water) conservation options." Europe's climate becomes "more like Siberia's" within the first decade. Crop yields and growing season lengths in key agricultural areas, including the US but possibly not Australia, "fall by 10-25 percent." Social unrest and wars occur, especially in nations already under economic and political stress, as a "more severe have, have-not mentality" takes over.

"With 815 million people receiving insufficient sustenance worldwide, some would say that as a globe, we're living well above our carrying capacity (already)..." they write. I'm one of those people, as I've mentioned in previous blog entries. But I'm also semi-optimistic; I hope we as a species can realize that such a climate change can best be handled through cooperation, not conflict. But they predict the US and Australia will turn inward, creating fortress nations that keep our supplies for ourselves, while keeping out hungry folks from elsewhere.

...More to come on this, I'm sure...

"The Cold and The Dark"

Authors: Paul Ehrlich, Carl Sagan, et al.
Norton & Co, 1984
Apocalypse Type: Nuclear (Non-fiction)
Rating: **** (of 5)


The first major book to really explore the science behind the concept of nuclear winter, this is -- and should be -- disturbing.

In case you're just off the ship from Mars, nuclear winter theory is the idea that a nuclear war over a certain number of warheads will trigger temperatures to plummet, especially in Northern Hemisphere lands distant from the ocean, with drastic consequences to many species including humans. They don't specify what that threshold is because no one knows, but responding to questions at the conference this book records, Carl Sagan said, "I think that to take out all major fixed strategic targets reliably, you have to exceed the nuclear winter threshold" (p33).

Sagan's group, best known as TTAPS#, explored numerous scenarios of various severity including attacks solely on cities (called "countervalue" targeting), attacks solely on military targets (called "counterforce" targeting), and mixed attacks hitting both urban areas and military sites. Based on a wide range of variables -- many of which they admit they couldn't quantify, and simply labeled as "synergisms" -- and atmospheric effects partly modeled on the massive globe-spanning dust storms of Mars, they argued that almost any exchange will exceed this threshold. If that happens, the theory says it will spark average temperatures to fall and stay cold for a time in proportion to the size of the exchange; just a few degrees for small ones down to -47 deg. C for the most severe scenario, taking more than a year to return to normal in some scenarios. They theorize that a major part of the freeze is caused clouds of soot from fires making Earth's surface far darker than normal, possibly too dark for people to see or plants to photosynthesize.

There is good news here (if we can call it that): sparking a new ice age is highly unlikely. Still, "it's very hard to see in any of these scenarios a situation in which the impact on people mediated through the ecological systems would not be at least as severe as the direct effects," Paul Ehrlich writes (p65). (Ehrlich, a biologist, wasn't an original TTAPS member.)

What he means is this: a nuclear war's effects would harm humanity from two different directions. First, millions die from the direct effects -- blast, fire, and fallout. Those effects are fairly short-term. Much longer-lived, and far less predictable, are the climatic changes; the radiation-induced mutations causing new diseases and fertility problems##; increases in ultraviolet sunlight once the skies clear; widespread radiation & other pollution for years; widespread destruction of fertile cropland; loss of vast quantities of fuel, data and technology; and the ripple effects the massacre of large swaths of the world's mammalian, bird and other species we depend on for food and less obvious "environmental services."

"The total number of people afflicted would certainly exceed one billion and might include everyone in the Northern Hemisphere," Ehrlich writes (p52). (For a somewhat technical summary of why environmental services are important, see an article by Thomas Deitz and Eugene Rosa here.)

"The survivors will be back in a kind of hunter and gatherer stage. But hunters and gatherers in the past have always had enormous cultural knowledge of their environments; they knew how to live off the land," Ehrlich writes (p59). Given that most people today in the major target countries are city-dwellers, that kind of knowledge is pretty uncommon, a fact that will certainly result in the starvation of many of those who actually survive the war itself. I suspect, though, that people will cobble together locally-varying kinds of scavenging systems and maybe very basic agriculture once canned goods are depleted.

Obviously, this idea has detractors, some of whom have argued that nuclear winter is more politics than science. One of those detractors hs been author Michael Crichton, who said the following in a Caltech speech in 2003:

What I have been suggesting to you is that nuclear winter was a meaningless formula, tricked out with bad science, for policy ends. It was political from the beginning, promoted in a well-orchestrated media campaign that had to be planned weeks or months in advance.

Further evidence of the political nature of the whole project can be found in the response to criticism. Although Richard Feynman was characteristically blunt, saying, "I really don't think these guys know what they're talking about," other prominent scientists were noticeably reticent. Freeman Dyson was quoted as saying "It's an absolutely atrocious piece of science but…who wants to be accused of being in favor of nuclear war?" And Victor Weisskopf said, "The science is terrible but---perhaps the psychology is good." The nuclear winter team followed up the publication of such comments with letters to the editors denying that these statements were ever made, though the scientists since then have subsequently confirmed their views.

That may be true; in fact, it's quite clear a major goal of the TTAPS group was to influence public perception of nuclear weapons and to express their great dislike of the weapons. As Yevgeniy Velikhov put it, "They are simply tools of suicide."

Brian Martin presents a pretty complete view of the politics behind the debate, but ultimately notes:

Just because 'politics' may be involved with nuclear winter research does not automatically mean that the research is scientifically wrong, tainted or inappropriate for use in policy-making. A straightforward response is to be aware of the political context of the research when evaluating it. For example, if the peace movement has provided the indirect or direct stimulation for doing the research, this may suggest that other social movements (or other strands of the peace movement) might have provided the incentive for different research or different emphases in nuclear winter research. If the background and experiences of key nuclear winter researchers lead them towards certain presuppositions in their model-building, such as an emphasis on worst cases, then this is something to be aware of, not necessarily something to be condemned. If nuclear winter research is defended on the basis of verifications (different scientists finding the same results from similar models) rather than attempted falsifications because verifications are better suited to promoting the theory, the implications of this for policy-making should be discussed.

Personally, I'm inclined to view the whole issue this way: even if the theory is seriously over-representing the consequences, can we afford to ignore it? If it's wrong but we get rid of nuclear weapons assuming it's right, we're in good shape. If it's right and we do the same, we're also in good shape. But we lose if we have a nuclear war whether it's right or wrong; the only difference is in the severity of the subsequent catastrophe. I suspect even the most severe war and its aftermath wouldn't cause our extinction, but would leave enough survivors for human populations to adapt and stabilize long-term at a neolithic subsistence level. What I doubt is whether we'd ever rediscover an industrial society afterward, since we've already used most of the fuel supplies that allowed us to create one this time.

*****

# TTAPS comes from its members' names -- Turco, Toon, Ackerman, Pollack and Sagan -- but is also a pun on the military music for funerals.

## Sloan-Kettering recently developed a drug that prevents this in female mice, although it would be just as hard to find as any other drug after a war.

(entry revised 6/13/05)