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The Forecast in the Streets

Filed under: — david @ 28 December 2007

The physical impacts of the global warming forecast can be bracketed with some degree of statistical confidence. Biological effects are more difficult to gauge, except in special cases such as the likely demise of polar bears that would result from the demise of Arctic sea ice. The societal effects, however, are nearly uncharted territory, at least to me. Perhaps the topic of global warming suffers from the same sort of cultural divide as university faculties, between the techies and the touchies; that is the sciences and the humanities. A new report (pdf) called The Age of Consequences, just released by the Center for Strategic and International Studies and the Center for a New American Security, tries to bring the social sciences, in particular history, geography, and political science, into the forecast of climate change in the coming century. It makes for fascinating if frightening reading.

The report was based on discussions of a group of senior luminaries with a wide range of expertise. I already knew or knew of and respect the climate scientists Mike MacCracken and Bob Correll, and Ralph Cicerone, head of the National Academy of Sciences. The group also included Nobel laureate Thomas Schelling, former CIA Director James Woolsey, former Chief of Staff to the President John Podesta, and former National Security Advisor to the Vice President Leon Fuerth. (Apparently not all group members, listed in the executive summary on page 8, got writing assignments, so not all of them are listed as authors.)

Images of the future can be constructed based on the lessons of history. The history chapter (beginning on page 26) begins with Table 1, which I will reprint here:

Event Potential deaths
Volcanic eruptions 104
Earthquakes 105
Floods 106
Droughts 107
Epidemics 108

It is sobering to note that the potential horsemen of climate change, floods, droughts, and epidemics, are all at the big end of this list. There is no historical precedent for the type of global multidimensional challenge that changing climate may bring, but there are common elements in societal responses to natural disasters, and many of the impacts of climate change will be regional in scope rather than global, like natural disasters.

The report considers the historical societal impacts of disasters ranging from bubonic plagues in the middle ages to Katrina. History teaches that people tend to return to religion in times of trouble, and to turn against people outside their social group. Governments are destabilized by hard times. Natural disasters tend to impact most strongly in less affluent parts of the world.

History also teaches that people have a tendency to develop ways of coping with environmental fragility, by choices of individual living strategies such as the ability to migrate, or by decisions made at the societal level, such as engineered flood control measures or mobilizing assistance from outside. The report offers the idea that it takes a population a few generations to learn how to operate within the limits of its natural world. For example, the report attributes the dust bowl drought in some measure to environmental inexperience of a population who had only recently migrated from more humid regions. With our recent increased mobility, and with climate change itself, we find ourselves losing this buffer of experience and understanding.

The group imagined three potential scenarios, labeled expected, severe, and catastrophic. These are not forecasts exactly, since forecasting society is even harder than forecasting climate, which is itself pretty dicey on a regional spatial scale, but rather a fleshing out of plausible possibilities, a story-telling, visualization-type exercise.

The “expected” scenario calls for 1.3 °C of warming globally above 1990 levels, by the year 2040. Changes in precipitation and sea level prompt migration at a scale sufficient to challenge the cohesion of nations. The potential responses to this scenario are broken down into specific regions with their particular historical and political settings. Just to pick a region at random, Nigeria in West Africa will suffer accelerated desertification with climate change, prompting intensified migration into the megacity of Lagos, which is itself threatened by sea level rise. Compounding Nigeria’s misfortune, there is oil in the Niger Delta, and as global oil supplies dwindle, the strife and corruption that oil brings a weak nation will only intensify.

In the “severe” scenario, the globe warms by 2.6 °C by 2040 and sea level rises about a half a meter. Scientists in 2040 conclude that the eventual collapse of Greenland and the West Antarctic ice sheets has become inevitable in the centuries that follow. Agricultural production declines in the arid subtropics and in increasingly flooded river deltas. Again to pick a random example from the report: the river systems in the American Southwest collapse, leading to impoverishment of Northern Mexico and increased migration pressure in the U.S. Resource stress in Latin American leads to a tendency toward populist, Chavez-type governments, and more extensive regions of de facto anarchy such as found today in parts of Colombia.

The “catastrophic” scenario assumes positive feedbacks in the carbon cycle to warm the planet by 5.6 °C by the year 2100, and sea level has risen by 2 meters. I feel compelled to note that if this is supposed to be a worst-case scenario, I personally can imagine worse in terms of sea level rise. In the social realm the crystal ball gets murkier as the report progresses from expected to severe to catastrophic, but one important ingredient in the prognosis for the catastrophic scenario is the migration of millions of people, a scale unprecedented in human history, potentially enough to undermine the stability of civilized governance. One participant recommended that we check out the movie Mad Max, only imagine it hotter.

There is far too much in this report for any sort of summary really to cover, and anyway I’m a techie rather than a touchie so my retread wouldn’t do the original report justice, but you get the idea. Results from the IPCC are summarized clearly, including regional climate projections, but the point is also made and discussed that climate forecasts tend to be in general conservative. In the arenas in which I have some competence to assess, the judgments the authors have made seem measured and fair to me. The report is authoritative and very meaty, bringing an astonishing array of perspectives and insights to the table. One could read this report and nothing else, and come away with a considerable expertise on the potential impacts of climate change. I highly recommend it to the readership of realclimate, and I look forward to reading your comments.

Thanks to Hank Roberts for digging this up.

363 Responses to “The Forecast in the Streets”

  1. 101
    Ray Ladbury says:

    Nick, Sorry for being unclear. We’ve seen precisely one generation where human population in a few countries has fallen. All I’m saying is that it is premature to look at that and draw definitive conclusions from it. Many nations (e.g. Germany) in which the birthrate has fallen have reacted with concern and actually taken steps to counteract the trend. Birth control has had some successes–most dramatically in China, where the resulting male-female imbalance all but ensures that there will be an outmigration of young males or further reduction in fertility. Indonesia’s voluntary campaign has had some success, but they’re still a long way from zero growth. Population control is still a dirty word in India and most of Latin America. Pacific Islanders have regulated population for generations, but I don’t advocate their methodologies.
    In the animal kingdom there are indeed some species that regulate population effectively. We’ve given no indication of being one of them.
    As to the crack about the brain, of course I realize the advantages as well as the costs. The thing is, while our species has been tremendously successful at expanding spatially, we haven’t been dominant that long, and we’ve given no indication that we are going to respond to the threats that now face us–in part because of our oversized cerebral cortex. There’s no real indication that we’re handling our situation any more intelligently than yeast in fermenting beer.

  2. 102
    Danny Bloom says:

    Regarding the posts about my “polar cities” post, above, I appreciate all the good and well-thought out replies, both pro and con, and those giving advice, and adding new perspectives, especially John Mashey’s 99 post. Thanks, everyone, for your responses. I am digesting what you’ve said and will put it my noggin for some more thinkin’.

    It’s hard to talk about such a wild concept as polar cities for the year 2500, because yes, nobody wants to talk about something so far away, and maybe undoable anyways, but I do want to add here, so everyone understands my concept better: my blog and posts about polar cities, which I began 12 months ago, is what I hope is a “non threatening thought experiment” mainly to get people thinking about taking action NOW, and to scare those people who still need scaring, not anyone here of course, into taking action about global warming NOW. So please look at my polar cities idea, what I also refer to as ARCTOPIA, as a kind of online guerilla theatre for these times. Some people have told me to give it up, others have emailed me and said “keep pushing the idea, it’s a good way to alert people who still need alerting.” That’s the main thing I am trying to do. I am not trying to convince any of you here. But you have given me good ideas as feedback, and that is what i wanted. Thanks.

    My guess is one day soon there WILL BE a govt report or a think tank report on “sustainable population retreats” (SPRs) in the future. As a post above said, this global warming thing entails science and it also entails society. I remain an optimist. I see humanity getting through this thing. But I am also reading all these very good posts here, and they are important. We need facts, and we also need visions.

  3. 103
    Steve Reynolds says:

    Ray Ladbury> …we’ve given no indication that we are going to respond to the threats that now face us–in part because of our oversized cerebral cortex.

    Of course, that depends on point of view. Some of us may be smart enough to avoid a stampede into unwise action that may have worse consequences than the original threat.

  4. 104

    Re #86 Susan:

    How is it possible for sealevel to not rise evenly?

    That is easy: because sea level rise is commonly measured/stated relative to the Earth’s crust, which may well move up or down itself. (A second, much smaller contribution may come from changes in the Earth’s gravity field due to redistribution of masses; we can neglect that here for this argument.)

    E.g., here in the South of Finland, according to tide gauge measurements, mean sea level is going down by some 4-5 mm/a. In reality this is due to the Fennoscandian post-glacial land uplift, which has been ongoing after the last ice age.

    In the Pacific there may be similar crustal uplift or subsidence phenomena ongoing, like moving away from a mid-oceanic ridge tends to cool and subside the crust — and islands with tide gauges on it — while just before diving into a trench or subduction zone, the crust tends to flex upward.

    It is very difficult to get a precise idea of the “true” or eustatic rise of sea level, indicative of the increase in ocean volume, this way. Most promising are satellite techniques, like the radar altimeters onboard Topex/Poseidon and Jason. Contrary to tide gauges, they monitor sea level in a geocentric (Earth centered) reference frame, not relative to the Earth crust, and they average over large ocean areas. The first advantage, geocentricity, also applies to GPS using the worldwide permanent IGS monitoring network. Co-location of tide gauges with GPS base stations is therefore recommended and becoming common.

    A problem with the satellite techniques is the still very short time base (couple of decades).

    Hope this helps

  5. 105

    Susan K writes:

    [[Is it possible for sea level to rise in some areas and not others?
    I see that some islands in Southeast Asia, Alaska, etc are going under. But little change is seen in sea levels in some other part of the world: just a couple centimeters or whatever. What is the explanation for that difference?
    How is it possible for sealevel to not rise evenly?

    Sea level is different in different areas of the world, due to differences in local water temperature and salinity, currents, the local shape of the Earth, and differential gravity due to the Earth’s rotation. Sea level rise refers only to the global average.

  6. 106

    Nick Gotts writes:

    [[Neither alters the facts that Malthus was wrong, that we know how to go about decreasing birth rates, and that in many countries, these are now below replacement level. Why are you so determined to deny or ignore these facts, and to be pessimistic about this?]]

    Contrary to popular belief, Malthus did not say people had to starve. He advocated practicing “moral restraint,” which he defined as couples not having sex after having had two children. Neither alters the facts that Malthus was wrong, that we know how to go about decreasing birth rates, and that in many countries, these are now below replacement level. A lot of misconceptions about Malthus can be laid aside by actually reading Malthus. Why are you so determined to deny or ignore these facts, and to be pessimistic about this?

  7. 107
    Bruce Tabor says:

    Mark R @ 75 and Susan K @ 80,
    I tend to agree with Mark on this. There is a tendency to censor comments about the politics of Climate Change on RC, probably to stop an already heated discussion boiling over.

    I do think climate scientists have a moral responsibility to inform the political debate if not lead it. This is tough, as politics and science are two entirely different thought processes. Jim Hansen is setting a marvelous example.

    I am growing increasingly pessimistic about humanity’s willingness to “get real” on climate change until things really start hurting. Of course it is possible we are looking at an extreme sci-fi scenario with global cities and Mad Max, but who cares. Nearly every participant on this blog will be dead if and when that eventuates.

    The threat we face long before that is the loss of a substantial proportion of the human (and other species) population of this planet, the likes of which have not been experienced since the Black Death in Europe when a third or more of the population died. It may be less serious, but it could also be far worse than that.

    This is something we can foresee as a realistic possibility. It is something those with foresight and the power to act (the “wise” men of Machiavelli) should be pulling out all stops to avoid. Living through a global calamity of this scale will not be pleasant. It is unlikely to doom humanity or reduce us to a breading pair in the arctic (a la Lovelock). But I personally do not wish to risk the possibility of myself, my family and my friends being among the hundreds of millions or billions of lives lost when the proverbial hits the fan.

    ps Happy New Year from Sydney, it’s just gone 12:00.

  8. 108
    Bruce Tabor says:

    S. Molnar @ 1 and 85,
    For what it’s worth I agree that the report has a Washington DC-centric worldview. I agree with your sentiments about its description of Latin American governments.

    The report is useful none-the-less.

  9. 109
    Ray Ladbury says:

    Steve Reynolds, Complacency is never indicative of wisdom. Timely action in the face of a threat–even if that action only buys additional time–is often necessary to avoid having action dictated by passion down the road. I think that it is telling that those who are most complacent are those who least understand the science.

  10. 110

    Thank you David for doing the heavy lifting, and to Hank for the detective work.
    The Executive Summary points out accurately that undeveloped countries will have less resources to adapt to climate change, and with the world being politically, and socially divided and volatile, lagely as a result
    of the gap between poor and developed nations, adaptation,which is being promoted by some in the current administration, is an idea worth reconsideration.

  11. 111

    Susan K.: as Barton writes (correctly) and I neglected to mention, also variations in temperature and salinity, as well as currents (and wind pile-up and air pressure variations, the s.c. inverse barometer effect), may affect sea level, and if the changes are secular in nature, turn up in the measurements as (local) sea level rise.

    As an example, the Gulf Stream is slightly tilted in the W-E direction due to the interaction of the flow velocity with the rotation of the Earth, the Coriolis effect. You could imagine that, if the Gulf Stream were to change course or strength, sea level as measured in many places would change, and this might produce a sea level rise signature.

    Actually the picture is complex. We describe the gravity field of the Earth by a surface called the geoid, which is a surface of constant energy that sea water would align with in the absence of currents, salinity gradients, etc. This geoid surface is somewhat irregular, deviating up to +/- 100 m from the regular, geocentric ellipsoid of revolution. Internal mass redistributions (like melting ice sheets) will change this geoid surface, and thus sea level, the small effect I was referring to.

    But also true sea level deviates from the geoid by up to a meter, due to the physical effects mentioned (currents etc.). The permanent part of this is called the sea surface topography, and its secular change will indeed show up in sea level measurements.

    But as said, the largest and obvious cause of sea level rise varying from point to point is failure to refer the measurement to the geocenter rather than the local Earth’s crust.

  12. 112

    RE #92, I’m not an archaeologist, so I don’t know how many civilizations have failed, but I remember reading that the ancient civilization in what is now Iraq failed due to land degradation due to increasing population pressures, and that the farmers knew what was happening (as we know GW portends to destroy our global civ), but they were caught up in having to continue degrading their land.

    I also have read that state-level societies (civilizations) — the newcomers on the block, only been around for some 5,000 years — are inherently unstable, compared to band and tribal level societies, due to political reasons, aside from environmental problems. Of course in our present destruction of our home (oikos), we’re not leaving much of a viable home even for tribal peoples.

    RE Danny’s polar cities & my mention of arks….I did start a futuristic novel some 15 years ago about the year 2085 (didn’t get past chapter 2). Many people were living in “hives” — these were mound complexes of six-plex homes in a circle, with a vegetable garden and fish pond in the center. The complex was covered with earth in a mound form, except for the center solarium garden. The idea was that with increasing heat, wild-fires, and tornadoes, this would offer better protection. There was also an underground pedway for when the weather was bad, linking mounds and the town for pedestrians, cycles, small EVs, also shops along the way (with water-tight submarine doors). This doubled as a flood control channel for the great floods. But this was no utopia, since the Federated States of America (capital in Kansas) could not keep renegade Floridians and people from other states cut off as hopeless areas (due to hurricanes, sea rise, etc) from crossing the border and wreaking revenge on the FSA people. And everyone hated our generations — calling us “doomers.”

    RE apocalyptic thinking (#84) — I take no pleasure in it (though my husband has accused me of doing so). I’m sincerely hoping the worst won’t happen, and despite our sinful behavior that may deserve punishment, I’m sincerely hoping we’ll get a reprieve. And I’m hoping those in power will have a change of heart and do the needful to avert this disaster…and also get a reprieve and avoid going to that place that’s a lot hotter than a globally warmed world.

  13. 113
    Susan K says:

    Martin and Barton, thank you!
    So, are these first island’s sealevel changes enough “warm water caused” to be attributable to climate disruption? Or is it mostly slowmoving underlying crust changes, and therefore part of the background unrelated to global warming?
    Or: would you attribute these early examples MORE to climate change? Or not till Wall Street looks like Venice…?

  14. 114
    Susan K says:


    I wish you’d finish that novel! Or even better, a screenplay. I am surprised that the movie industry has not seen its way to telling this horror story that will befall us all.

    Surely it is THE story for our species, (and all those other ones too).

  15. 115
    Aaron Lewis says:

    The IPCC does not model ice dynamics and therefore does not properly account for sea level changes. Since much of our economic infrastructure is at sea level, a proper accounting of sea level changes is essential to understanding the impact of global warming on society.

    The following seems jumbled because I am not taking the space to develop and relate the concepts.

    Consider the oil industry. At a sea level change of less than a meter per century, their oil production and refining facilities have substantial residual value. At some higher rate of sea level rise, those capital structures lose value and must be written off. The end of cheap oil could come when the oil industry realizes that they really will have to abandon current refinery, petrochemical, and production facilities near sea level. This decision may be purely a matter of the psychology of the managers and their accountants, which may, or may not be tied, to any particular physical event.

    The end of cheap oil will dramatically affect our agricultural industry. Currently, it is common to use 30 or 50 calories of petroleum energy to produce and deliver one calorie of human food energy. That will change.

    With expensive oil, “globalization” is less attractive as an economic buzz word. Even at the smallest scale, human settlements must be energy efficient. Diffuse settlements (suburbia) will become very costly. In short, expensive oil brings about a cascade of unpleasant social effects.

    There are actual physical events stemming from global warming that are not fully addressed either. The authors do not seem to have an appreciation of the complexity and fragility of the agricultural-industrial complex that provides food for most of the world’s population. A fault tree analysis of agricultural systems suggests a cascade of failures as weather events exceed the original design conditions of modern engineered agricultural systems.

    Time was, after a flood you could replant as soon as things dried out enough to work the soil. However, with modern drained/irrigated/engineered fields, they must rebuild infrastructure after a flood and before they plant another crop. Moreover, anything that disrupts very complex supply and maintenance chains put agricultural systems in jeopardy. Finally, the current agricultural system is hugely subsidized by cheap oil. Anything that disrupts cheap oil, disrupts our supplies of cheap food. Our oil supply infrastructure was engineered for a particular climate. If climate changes fast enough, the oil system will fail. Think about what happens every time a hurricane goes through the Gulf of Mexico. This year for the first time, we had two category 5 hurricanes in the Gulf of Mexico (and the first typhoon in the Gulf of Oman in recent times.)

    Do the fault tree analysis for sea level change. Current agriculture needs cheap oil. Oil refining is mostly at sea level. Any significant change in sea level requires the refineries be “jacked-up”. However, the plants that make the steel pipe for refinery repair are also at sea level. So are the plants that make some the required plastics. Any significant change in sea level means a disruption in refining capacity. An extended disruption in refining capacity means cheap oil is at an end. Moving a refinery is a big deal.

    How suddenly could we move from cheap oil to oil that included the cost of new refineries, petrochemical plants and production facilities? All it would take is one big ice flow that produced a measurable change in sea level and scared an oil executive. Global grain stock carryovers have been declining for the last decade. We are one crop failure away from real food shortage. Drought in Australia or the US would be a problem. We have very fragile world food supply. There is no excess capacity to cushion the impact of a season of poor crop production anywhere in the world. Expensive oil makes it less likely that land will be planted, and thus more likely for a single crop failure to have an impact on the global economy.

    I live in California. Just looked out of my office and saw pear trees blooming – 4 months early. (That was yesterday. The buds froze last night. That is agricultural infrastructure that was damaged by global warming – yesterday! I guess I can write off my 2008 pear crop.)

    Welcome to the reality of global warming. That reality is not reflected in the subject report.

    I am not all doom and gloom. There are solutions, but this report does not even hint at how vital it is to take action now.

  16. 116
    Ray Ladbury says:

    Barton and Nick, Re: Malthus, I really am not trying to be perverse. However, I hear from many quarters that population is a non-issue, that all we have to do is a)make everybody prosperous, b)educate/empower all the women, c)get everybody to exercise “moral restraint, d)end marriage, e)end male hegemony, f)make birth control freely available… Interestingly, the solution often bears a strong resemblance to the political agenda of the speaker. Now, with the exception of ending marriage, I favor most of these ends as well, but I am a little reluctant to draw conclusions while 1)we have less than a generation’s worth of data on countries’ birth rates dropping down to replacement, 2)Global population is still increasing, 3)we are depleting Earth’s resources faster than ever. This makes me a little reluctant to say, “Malthus was wrong,” and declare victory. Hell, Darwin was wrong, too, about some things. I’m just afraid I don’t find a great deal of room for optimism when people are still debating whether a physical system with nearly unknown positive feedbacks might pose a stability concern.

  17. 117
    Chuck Booth says:

    Re # 40 Phil McCracken

    While your colleagues at work may not take AGW seriously, the governors of the New England states and Premiers of the Eastern Canadian provinces have been quite proactive in setting goals for reducing the emission of GHGs (to 1990 levels by 2010; to 10% below 1990 levels by 2020; and a long-term reduction of 75-85% from current emission levels).
    Climate Change Roadmap for New England and Eastern Canada – Summary Recommendations. Environment Northeast,

    That’s not to say the states and provinces are making good progress towards those goals, but at least their governments are taking it seriously, even if some citizens are not.

  18. 118
    JCH says:

    Are these claims a mistake?

    Expert: Global warming fueling ‘mega-fires’ –

    Sea levels may rise 5 feet by 2100 –

  19. 119
    Philippe Chantreau says:

    I tend to agree with Ray. Malthus may have been wrong only in the sense that he did not foresee how well we could manage to extract resources from our world.

    Looking for instance at Indonesia, I find it hard to believe that the country will fare well if its population keeps increasing at the rate it has, and it continues managing its resources and people the way it has. There are many like examples.

    And it is not because western countries have taken a certain route at a point in their history/development, that all other countries will go similar ways.

    The question is, what are the true manifestations of hitting the limits for a population in a a specific set of circumstances, involving all natural factors (resources, climate etc…) and other aspects such as technology, culture and so forth. There is no assurance that anything catastrophic will happen to reveal the blaring truth. Signs may be more subtle, yet lead to a similar end. We unfortunately tend to focus on the spectacular stuff, on this subject as much as on climate change. However, this is an extremely complex question, way beyond the insight of a single person, would that be Malthus or anyone else. That does not mean that his insight was entirely wrong, perhaps just too simplistic.

  20. 120
    Jim Galasyn says:

    Speaking of Malthus:

    No Connection Between Environmental Crises And Armed Conflict, New Study Argues

    … Of course people fight over resources, that’s not our argument. We believe, rather, that we have a strong scientific case against the Neomalthusian model, says Binningsbø. …

  21. 121

    Ray —

    I agree that Malthus wasn’t wrong. My last post on the subject was a little incoherent because it got mixed up with parts of the post I was responding to. My only point there was that Malthus didn’t say starvation was inevitable.

  22. 122
    rick says:

    Re #40
    I live in Upstate NY and I haven’t experienced a bitterly cold March or April in my lifetime. Snow, yes. But no bitter cold. Since the 70’s we rarely see temps. below 0 F!

  23. 123
    Nick Gotts says:

    Re #106 (Barton Paul Levenson)

    “Contrary to popular belief, Malthus did not say people had to starve. He advocated practicing “moral restraint,” which he defined as couples not having sex after having had two children. Neither alters the facts that Malthus was wrong, that we know how to go about decreasing birth rates, and that in many countries, these are now below replacement level. A lot of misconceptions about Malthus can be laid aside by actually reading Malthus. Why are you so determined to deny or ignore these facts, and to be pessimistic about this?”

    Barton, I’m not sure what point you were trying to make, particularly in your last sentence. I quoted from Malthus (1798) “An Essay on the Principle of Population, as it Affects the Future Improvement of Society with Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers.”, and pointed out where he went wrong in this work, which is the one modern “Malthusians” such as Ray Ladbury seem to base their views on. In his 1798 work, Malthus gives no sign of believing that “moral restraint” is capable of counteracting the tendency of population to increase geometrically. I am aware he modified these views in his 1803 revision “An Essay on the Principle of Population; or a View of its past and present Effects on Human Happiness; with an Inquiry into our Prospects respecting the Removal or Mitigation of the Evils which it occasions”, although it is quite clear he was not in favour of contraception, at any period.

  24. 124
    Jim Galasyn says:

    Re the Malthus discussion, shouldn’t we be discussing the more modern idea of carrying capacity, and whether it’s appropriately applied to humans? Presumably, the only reason it wouldn’t apply to humans is due to human ingenuity.

    Maybe the question should be: Is human ingenuity sufficient to overcome the biological constraints that apply to every other organism on Earth?

  25. 125
    Jim Galasyn says:

    Re JCH’s question about megafires in 118, I watched that 60 Minutes story — there was some amazing footage of land transforming from forest to savannah: thousands of black, dead tree skeletons rising from new desert floor.

    As the topics expand and desertification accelerates, it seems inevitable that megafires and deforestation will result.

  26. 126
    P Lenihan says:

    1. There is accurate polar bear population data. They are increasing in number throughout the Arctic.

    2. What is the best case scenario regarding CO2 accumulation if we continue the status quo approach, that is supporting Kyoto, but increasing emissions everywhere? You have already informed us about the worst case scenario.

  27. 127

    Re #113 Susan K: I would be very reluctant to draw any hard conclusions concerning global warming / eustatic sea level rise from individual island sites, or even several such sites. The key is careful reduction and realistic error analysis on data sets of global validity and appropriate time base. (I have done some tide gauge analysis in a previous life.)

    There is no royal road to insight :-(

  28. 128
    pbview says:

    My question is: How many times in the last 50,000 years of the Polar bear has their enviorment changed? Have they adapted?

  29. 129
    Nick Gotts says:

    Re #122 (Jim Galasyn) “Maybe the question should be: Is human ingenuity sufficient to overcome the biological constraints that apply to every other organism on Earth?”

    I think all those of us who accept the reality of AGW would probably agree that the answer is “no”: at least so long as Malthus’ first proposition “That population cannot increase without the means of subsistence”, holds. I suppose if we were all “uploaded” as the Singularitarians suggest, we would have overcome those constraints, but would no longer be human, at least in a biological sense.

  30. 130
    Nick Gotts says:

    Re #126 (P. Lenihan) “There is accurate polar bear population data. They are increasing in number throughout the Arctic.”

    Where do you get this information? The most recent relevant peer-reviewed paper I found in a brief search (Research and Practice in Social Sciences Dowsley, M Vol. 2, No. 2 (Feb. 2007) 53-74
    “Inuit Perspectives on Polar Bears (Ursus maritimus) and Climate
    Change in Baffin Bay, Nunavut, Canada”) does not support the claim, and several sources suggest data simply is not good enough to make any definite statement about their numbers increasing or decreasing.

  31. 131
    Jim Galasyn says:

    IUCN Polar Bear population estimates.

    Btw, I had to trim most of this post away, due to the thrice-damned WordPress spam filter, which won’t tell me which words it considers to be spam.

  32. 132
    Nick Gotts says:

    Re #116 (Ray Ladbury) “Nick, Re: Malthus, I really am not trying to be perverse. However, I hear from many quarters that population is a non-issue”
    From what quarters? Be specific please. What I hear much more frequently are complaints that “population is increasing exponentially” (it isn’t) – e.g. from Barton Paul Levenson and others on this site not long ago; and that “population is a taboo subject” (it isn’t) e.g. from
    – and almost invariably, these claims are from people who have not bothered to find out what is actually happening to population at present, and thought likely to happen over the next few decades. Population growth rates have declined markedly in almost every country since the global peak in the late 1960s – globally they have roughly halved, and absolute population growth (annual surplus of births over deaths) has almost certainly been falling since around 2000. Urban populations everywhere have lower growth rates than the nearby rural populations, and people are moving to urban areas. We should not be complacent, we should oppose restrictions on contraception and abortion, we should oppose “pro-natalist” policies, including in countries where populations are declining (or would without immigration), above all we should educate and empower girls and women. However, we should also recognise that the bleats of “population is the real problem”, “population is a taboo subject” etc. provide a handy way of blaming the poor for the problems which we, the rich, have largely caused – and that sometimes (I am certainly not accusing anyone posting here) “there are too many people” is a coded way of saying “there are too many black/brown/yellow people”.

  33. 133
    ChrisC says:


    As others have stated already, there are many factors that affect sea level. Subsidence or ascent of land mass affects RELATIVE sea level rise (ie, the sea level at a certain coastal location) and may indirectly affect absolute sea level in certain locations by displacement (ie. clogging up an inlet or something similar). Local variations in sea level are caused by changes in salinity, atmospheric pressure, ocean and atmospheric temperature and wind.

    One of my favourite examples in the equatorial pacific. Trade wind flow (regular east/south-easterly winds across the tropics) pushes on the water, causing it to “build up” on the western side of the Pacific basin near Australia. The fact that to sea level is higher at one side of the pacific than the other drives a “sub-surface counter current” that we can measure.

    Large scale atmospheric phenomena, like Hurricanes can also significantly affect sea level. Check out this cool site to see how sea-level is changing on a short term basis:

    With regards to your second question, it’s very diffucult to attribute the relative sea-level rise at any one site to any one cause. Depending on the island, it could be induced by land rise/subsidence, erosion, thermal expansion of ocean water ect… However, what we do know is that as the oceans warm, the water is expected to expand, leading to a rise in sea level. Carefull measurements made over decades by satellites and tide gauges over a number of sites have detected an increasing trend that is close to what we would expect (actually a little bit more), which lends evidence to this idea.

    However, in climte, it is very difficult to ever nail down an phenomena to a single cause. However, the evidence so far suggests that warming of the oceans is contributing to sea level rise.

  34. 134
    Philippe Chantreau says:

    Re 124: that is truly the right qestion. Ingenuity will push away the constraints but up to a certain point only. Then, quality of life will decrease, obviously starting with the most vulnerable (poor). They are likely to bear the blunt of that decrease for a while, but past a certain point, more and more will see their quality of life decrease. However, the exact ways and rates at which this will all manifest is really hard to foresee.

    Stabilizing total population close enough to its current level, or even up to 8-9 billions is not necessarily so bad (if a good bunch of it is urban), as long as we can manage the energy problem and the climate does not make food production too much of a problem, and the ecosystems remain functional, and most places adopt adequate environmental regulations (lots of ifs).

  35. 135
    EricL says:

    Nick, thanks for your efforts on this re Malthus. The Malthusian meme is interesting in so far as it seems reasonable at first glance but collapses totally when Malthus’ original arguments are actually examined in context and put to the test of the evidence. I gather the same goes for Hardin’s tragedy of the commons, which again looks like a great idea but apparently doesn’t match most cases of actual commons management by human beings. But these two ideas are now central doctrine in terms of pop ecology and most people cannot be disabused of them. (I mean this generally: no slur on Ray Ladbury!)

  36. 136
    James says:

    Re #132: [What I hear much more frequently are complaints that “population is increasing exponentially” (it isn’t)…]

    Could you perhaps offer some evidence to back up that claim? I certainly don’t see any evidence that they’re not, even if the exponential factor may have changed. Population growth rates may have declined, but they’re still growth rates. As with CO2 increase, as long as the rate’s positive, the problem is still there.

    As for knowing how to deal with the problem, yes, we know several ways, but none that is likely to work without (at the very least) a totalitarian government willing and able to impose it by force, as with China’s one child per family program.

  37. 137
    Danny Bloom says:

    For John Mashey, Post 99 above, Lynn, David, Hank, and others who have looked at my polar cities blog and read some of my posts here, there’s a new interview with me on a radio station in Vancouver, Canada, here, just ten minutes long, in the middle, from minute 22:40 seconds to minute 32 or so, and people have told me that the radio interview explains what I am doing much better than my print comments. So if time allows, take a listen:

    May 2008 be an important year in our understanding of just what it is we face in terms of climate change. The momentum is building in most Western countries, but I fear the rest of the world could care less. They want what the West has, or what they see on TV and Hollywood movies. They even want blue eyes and blond hair. Sigh. So sad. Globalization has gone a bit too far, I fear. Anyways, this is an important blog and I appreciate the mods letting me participate from time to time…

  38. 138
    Philippe Chantreau says:

    Eric L, I would like to know better what you are referring to with the Tragedy of the Commons idea. From my own obervation and research, it appears that, at least for preservations of areas where ecosystems proceed with minimum human disturbance (natural parks, reserves, etc…), public works somewhat better than private (esp. large areas). Some try to include the oceans in this commons idea and I think it is a pretty bad example, kind of like the atmosphere as a whole, although technically they are the ultimate commons. People’s perceptions are what matter and they are not yet ready to perceive some things as areas of responsibility. A large chunk of land (with a map for it) can be worked in the public’s psyche. The air or the ocean, in general, can’t, yet.

  39. 139
    Ray Ladbury says:

    Nick Gotts, Latest estimate has global population growing at 1.167%–still exponential, with a doubling time of ~59 years. Yes, that is much lower than the ’60s. It is still not sustainable. I’m a bit reluctant to risk civilization’s future on extrapolation of a 30 year trend. And you rightly point out that it is not just population, but growth of consumption that is the problem–and since increased resources will be essential to the very forces you say are behind falling population growth rates, will they be sustained in the future? It may well be that we are already beyond the carrying capacity of the planet. Certainly we are doing serious harm to the ecosystems thereof. Malthus may have already proven right wrt the human species. And even if he is not right yet, he is not wrong until humans actually find a way to live in a sustainable manner–in terms of population, resource consumption and even social support systems.
    I really don’t think that this will “just happen” as a result of some fortunate confluence of trends or of our humanity. Perhaps “moral restraint” is not the key to avoiding a Malthusian collapse, but certainly it will take some form of restraint.

  40. 140
    Bruce Tabor says:

    Re 136 James,
    Try this US Census Bureau site:
    I think one thing we would all agree on is that if population was increasing approximately exponentially then the change (increase) from year to year would also increase. If the change from year to year was constant then growth would be linear. The largest increase was nearly 88 million in 1989. Since then the annual increase has been steadily declining and is now (2007) about 77 million. This is not even a linear growth rate. I’ve tried to reproduce the table for 1989 to 2007. The site projects out to 2050, by which time world population is projected to be 9.4 billion with an annual growth of about 46 million.

    Year Population (%) Increase
    1989 5,185,743,040 1.68 87,671,844
    1990 5,273,414,884 1.58 83,805,575
    1991 5,357,220,459 1.54 83,275,568
    1992 5,440,496,027 1.47 80,816,729
    1993 5,521,312,756 1.43 79,720,422
    1994 5,601,033,178 1.43 80,645,018
    1995 5,681,678,196 1.40 79,930,775
    1996 5,761,608,971 1.36 78,965,934
    1997 5,840,574,905 1.33 78,141,183
    1998 5,918,716,088 1.29 76,883,801
    1999 5,995,599,889 1.26 76,111,007
    2000 6,071,710,896 1.24 75,825,101
    2001 6,147,535,997 1.21 75,015,718
    2002 6,222,551,715 1.20 74,894,185
    2003 6,297,445,900 1.19 75,483,901
    2004 6,372,929,801 1.19 76,207,322
    2005 6,449,137,123 1.18 76,422,087
    2006 6,525,559,210 1.17 76,715,602
    2007 6,602,274,812 1.16 77,257,452

  41. 141
    Bruce Tabor says:

    Re Aaron @ 115 , Jim @ 124, Phillipe @ 134 and others:
    There are at least two schools of thought that suggest that the very complexity and energy required to maintain our civilisation carries the seeds of its ultimate collapse. We have overcome (temporarily) the Malthusian environmental constraints fundamentally by using enormous amounts of fossil fuel energy, but that carries with it a high cost in the complexity (and lack of resilience) of the infrastructure required to maintain modern farming.

    Joseph Tainter maintains that these increasing investments in social complexity reach a point of diminishing marginal returns. At some point additional investment in complexity creates zero return and collapse is a natural result.

    The field of Complex Adaptive Systems (especially the John H. Holland view) also posits cycles of emergence, growth, increasing complexity combined with eventually declining resilience, perturbation and collapse, folowed by re-emergence. These are natural and somewhat inevitable processes in such systems.

    I find these ideas enticing and seductive, but ultimately only useful retrospectively when used to describe human societies. It is difficult to work out how to even measure the variables in these systems let alone use them to make predictions about human societies. Maybe someone will set me right.

    In the words of our discussion host, I’m a techie not a touchie.

  42. 142
    Ark says:

    @Bruce Tabor (140). Your own table shows that the “steady decline” in increases stopped in 2002. After that the yearly increase grew again from 74.9 million in 2002 to 77.3 million in 2007. Luckily the percentage growth is still decreasing.

  43. 143
    dhogaza says:

    Btw, I had to trim most of this post away, due to the thrice-damned WordPress spam filter, which won’t tell me which words it considers to be spam.

    Of course it won’t. If it did, the spammers would simply avoid those words …

  44. 144
    dhogaza says:

    The world’s leading polar bear scientists reported that of the 19 subpopulations of polar bears, five were declining, five were stable, two were increasing, and seven had insufficient data to make a determination.

    This does not support your contention that numbers are increasing “throughout the Artic”.

    I tried to post more, but that post was flagged as spam, so don’t feel too bad about yours having been flagged.

  45. 145

    James writes:

    [[As for knowing how to deal with the problem, yes, we know several ways, but none that is likely to work without (at the very least) a totalitarian government willing and able to impose it by force, as with China’s one child per family program.]]

    Actually, voluntary programs have made great strides in many countries. Bangladesh, once dismissed as a basket case, has managed to lower its lifetime fertility rate from seven children per woman to three. That’s not replacement level yet, but it’s getting there. When I was born (1960) population was rising at about 2.0% per year; now it’s down to 1.3%. You’re right that it should decline further, but we probably won’t need totalitarian control of the Chinese variety.

  46. 146
    Nick Gotts says:

    Re #136 (James), 139 (Ray Ladbury) “Latest estimate has global population growing at 1.167%–still exponential, with a doubling time of ~59 years.” Ray, I would have expected you at least to know what exponential growth means: that the proportional rate of change remains the same. It is not doing so; it is falling, and has been doing so fairly steadily for 40 years. As Bruce points out – I’d be cautious about the accuracy of the figures he uses to show sublinear growth, as counting people is non-trivial – but that growth has been subexponential for several decades is really not in doubt. Malthus’s (1798) contention that population would invariably grow if sustenance was available has been proved wrong by the experience of Japan. These are matters of fact, not opinion. Once people stop pretending otherwise, we might have a sensible discussion about population. Incidentally, Ray, I notice you don’t actually give any specific sources for claims that population is not a problem.

    Re #135 (EricL) Eric, yes, I’d agree completely about Hardin: what he should have called the phenomenon is “The Tragedy of the Open-Access Regime”. Real, historical commons were/are governed by complex rules and mutual surveillance. George Monbiot wrote a Scientific American essay “The Tragedy of Enclosure” on this (jan 1994). He says Hardin’s sound-bite has been used to justify nationalising (and subsequently, in most cases, privatizing) commons in many countries, impoverishing those who had rights of use in them.

    I wrote a review of a large sample of the multi-disciplinary literature on “social dilemmas” which some people may be able to get hold of:
    Gotts, N.M., Polhill, J.G. and Law, A.N.R. (2003) “Agent-based social simulation in the study of social dilemmas” Artificial Intelligence Review, 19 (1):3-92. It’s more general than the title might suggest.

  47. 147
    Lawrence Coleman says:

    I also read a report from Utrecht university which explained the chain of events in the Paleocene-Eocene thermal maximum (PETM), 55 million years ago which caused the temp of the artic regions to exceed 24C in a runaway greenhouse effect condition. Increased volcanic activity pushed the level of CO2 beyond the tipping point which raised the global temp sufficiently to release vast quantities of methane stored under the oceans as hydrates to excape into the atmosphere thus compounding the temp rise. One also assumes that the methane stored in the tundra would have aslo been released. Tropical algae flourished at the north pole. So that little example shows what happened when mother nature is pushed to beyong breaking point. By all highest level accounts we are reaching that level now. I am currently reading The age of consequences…very thorough report I must say! It’s great ammunition in the fight to get our respective governments to take IMMEDIATE action.

  48. 148
    Ray Ladbury says:

    Nick Gotts, Eric L., Jim Glasslyn et al., Keep in mind that Malthus was writing in 1798. Surely it is not reasonable to hold him to a higher standard than that to which we hold, for example, Darwin or J. C. Maxwell. Yes, elements of his treatise were incorrect. However, it was a vast improvement over the panglossian vision of Condorcet, and I would contend that the basic tenet–that population cannot expand indefinitely without outstripping its food supply, etc.–is correct.
    Yes, birth rates are falling. That’s good. However, some countries are trying to counter that trend (e.g. Russia and Germany). Also, when you look at the reasons people give for having future children, the expense of raising children figures heavily. Doesn’t this reflect a tightening of availability of resources for survival. And in response, how are they having fewer children? Contraception is a big factor–actually mentioned by Malthus (called a vice).
    Given the rather precarious state we have put our environment in while attempting to feed 6 billion people, I think it is a bit premature to declare victory over Malthus–particularly if we extend to him the liberality of interpretation we extend to other scientists of the 18th and 19th century.

  49. 149
    Nick Gotts says:

    Re #148 (Ray Ladbury) Good: you agree that Malthus (1798) (for whom I have great respect as a pioneer of social science) was wrong on the key point that population must rise if sustenance is available, and you agree that population is not growing exponentially – at least, that’s how I interpret your post. Now a productive discussion is possible. As I’ve made clear repeatedly, I don’t say population growth is not a problem, so we’re agreed there.

    “when you look at the reasons people give for having future children, the expense of raising children figures heavily. Doesn’t this reflect a tightening of availability of resources for survival.”

    No, if you’re talking about rich countries, particularly those with a decent welfare state, where children do not starve unless their parents or parent-substitutes starve them.(Malthus, wrongly, thought that a welfare state, which is more or less what Condorcet advocated, would lead to a sharp rise in birth-rates.) It may do so in the former USSR, where the transition from statism to kleptocracy has impoverished most people; but a collapse in morale, resulting in increased alcoholism among men and hence a perception by many women that they cannot be relied on for any help, is probably also important. In rich countries it may sometimes reflect a tightening of availability of resources to keep yourself and prospective children in the manner you aspire to. More generally, whether to have children, and how many, is mainly a “lifestyle choice” in urban societies – they are one “luxury” among many available. From this point of view, the need is to ensure that people can live enjoyable and satisfying lives both without children and while cutting their GHG production; to minimise social pressures, particularly on women, to reproduce; and to make it as easy as possible for those who want to, to have sex without risking having children. Here again Condorcet, a contraceptive pioneer, scores over Malthus, who, as you say, regarded contraception as “vice”.

  50. 150
    Phil McCracken says:

    So, can I be on the committee that decides who lives and who, er, takes one for the team?