Date: Wed, 13 Sep 1995 23:56:35 CST From: "jim blair" BCc: Subject: CO2 & Global Warming: S/N or "Compared to What?" CO2 & Global Warming: S/N or "Compared to What?" Green house gases: the real issues. This post is largely in response to recent articles about global warming that have appeared in The Economist, April 1-7 (Global Warming and Cooling Enthusiasm p33, and Reading the Patterns p65) and in National Review, May 1 (Hot Air in Berlin p18). These articles were topical because of the United Nations Climate Conference in Berlin last month. The first Economist article is mostly about the international politics of the debate: OPEC nations strongly oppose any action to reduce emissions since "greenhouse gases" means mostly CO2 which comes from burning petroleum. Low islands and countries with low sea coast regions are more interested in doing something. Poor countries don't want their energy options limited before the can industrialize--unless they are compensated. The rich energy efficient nations of Europe made promises to reduce emissions, but now, faced with KEEPING them, are losing enthusiasm. But my concern here is with the science: Will current practice alter the climate of the earth? WHAT GAS? Every object emits energy depending on its temperature:("black body" radiation). The hotter the object the shorter the wavelength. For very hot objects the radiation can be seen, as in "red hot", or if even hotter, "white hot". For cooler objects, you can't see the energy, but it is still there as infrared (IR) which you may feel as heat, or microwave which you can't feel. A sidewinder snake can find a mouse in the dark by detecting the heat the mouse emits. The earth emits in the long IR. Even the black empty space of the universe emits 7.35 cm radio energy, corresponding to 3 degrees K, heat left over from the Big Bang. Polyatomic gas molecules absorb long IR and microwave energy when they tumble. CO2, with 3 atoms per molecule does this. So does methane (CH4) and water vapor (H2O). These gases in the air absorb IR energy that the earth would otherwise radiate into space. They act like a blanket. INSERT COMMENT--- >Greenhouse gases do not "absorb" heat. They make the atmosphere less >transparent to the infrared. Hi, I think it perfectly acceptable to say that CO2 "absorbs heat". Infrared radiation that would otherwise pass through an atmosphere goes in one side (here the bottom) and does not come out the top. It has been "absorbed". The energy of the IR is transferred to the CO2 molecules causing them to tumble faster, and this transfers some of the energy formerly in the IR radiation to the other gases in the atmosphere by the collisions. They then move faster. This is commonly called being "warmer". If anyone thinks that the transfer of IR energy (commonly called "heat") into the earth's atmosphere will not result in ANY change, they should offer some explanation as to just what they think happens to that extra energy. And besides MORE energy there is also a change in the energy distribution of the atmosphere. More heat absorbed in the lower atmosphere would mean less made it to the upper atmosphere: the lower would be warmer, but the upper would be cooler. So to measure this effect, it is important just which part of the atmosphere is examined. END OF INSERT--- WHO, US? Human activity releases CO2 from the fossil fuels that we burn, especially since the industrial revolution. The CO2 level in the air has been monitored since the 1950's and is increasing. Besides a natural annual change (it drops each spring as plants grow and rises each fall as leaves decay), there has been a steady background rise of about 20% in the past 100 years. This is caused by humans. And it should cause the earth to get warmer. Nearly 100 years ago the Swedish chemist Svante Arrhenius and the American geologist Thomas C. Chamberlin independently advanced the hypothesis that changes in the abundance of carbon dioxide in the atmosphere would affect the surface temperature of the earth. Arrhenius estimated that a doubling of the concentration would cause a global warming of about nine degrees C. In 1939 G. S. Callendar suggested that the global warming observed over the previous 60 years might have been caused by an increase in atmospheric carbon dioxide from the burning of fossil fuels. Gilbert N. Plass argued along similar lines in the early 1950's. Anthropogenic Global Warming does have some critics: see the link to A Skeptical View on my web page When coal burns it also releases small particles and SO2 which forms small droplets: these reflect incoming sunlight and cool the earth. This offsets the warming effect of CO2, but the relative balance is in dispute. Some claim that from a climate perspective, "dirty coal" is better than "clean coal". Also there is a "law of diminishing returns" here. Maybe CO2 levels are already high enough that more does not make much more difference. THE REAL ISSUE: COMPARED TO WHAT? The other two articles cited both view the problem as a "signal-to-noise ratio" problem, and so do most who discuss it. Is the earth actually warming? Can the warming "signal" be measured against the natural variations in temperature "noise level"? But they misunderstand the nature of the problem: it is actually a "compared-to-what" problem. What is the basis of the comparison? That is, is the earth warmer than WHAT? Humans have been raising the CO2 level for several hundred years. The earth was warning up as expected until about 1940, but has not warmed up as much as predicted since then. The implied comparison is to a "flat" baseline of constant temperature. There is no "control earth" without a build up of CO2 to compare to. But the proper comparison is to the EXPECTED temperature. I am surprised no one else seems to understand this because I thought it was common knowledge that history has been characterized by warm and cold cycles of 50 to 100 year duration, for example, ice skating and winter fairs on the Thames river in London during the "little ice age" of the 17th century. WHERE DID the LITTLE ICE AGE GO? GLOBAL WARMING ATE IT! Studies of the ice cores drilled in the Greenland glacier suggest a pattern of cold spells based on the superposition of two cycles: 80 years and 180 years. The causes of this complex pattern is not known (but there is some C-14 evidence that the 180 cycle may be due to changes in the sun). At any rate this pattern fits all the cold spells since 1200 A.D.--except that we should NOW be in a cold period that SHOULD HAVE STARTED about 1950 and continue until about 2000 A.D. These results were published in the 1970's. The cycles are associated with Willy Dansgaard, and are discussed in the chapter on the history of climate in the text book GEOLOGY TODAY from CRM. See Figure 1 for the past record of warm and cold spells since 1200 AD, and the predicted "little Ice Age of 1970-2000 AD. At about the same time, the proponents of the greenhouse effect were predicting a global warming, but they did not consider the natural climate cycle. Since neither the predicted warming nor the predicted cold spell has happened, the conventual wisdom is that both ideas are wrong. I think it is at least as likely that BOTH are CORRECT: but since 1950 the two have been canceling each other out. Just when the natural cool period was beginning to weaken, the eruption of Mt. Pinatubo produced a few years of extended cooling. Now that effect is wearing off, and the natural cold cycle will give way to a warm cycle which will ADD to the greenhouse warming rather than subtract from it. Things should warm up in the next decade. See Figure 2 for how the expected cold spell is greatly reduced by the effect of the CO2 increase. The TWISTED POLITICS of ENERGY There is a strange political component to what should be a technical- scientific question. The Left believes in the green-house effect and the Right doubts it. But the Left opposes nuclear power while the Right supports it. When the dangers of CO2 are understood, the greenhouse effect is a compelling argument for shutting down coal and gas power plants, and only nuclear ones can replace them - at least in the short run. Solar or wind is not yet capable of replacing the coal plants. Steam turbine natural gas (ie methane) has been proposed as an alternative, but although methane releases less CO2 per kilowatt of electricity generated, it still burns to CO2. And the more it is used, the more will leak or spill into the atmosphere, where it is much more effective as a greenhouse gas than CO2. Until the collapse of the Soviet Union, the three major objections to the use of nuclear reactors to generate electric power were the mining of uranium, the safety of the reactor operation, and the disposal of the reactor waste products. No one seems to realize that it is a different world today. The former Soviet Republics have about 28,000 nuclear warheads, and the US about as many. They contain enough uranium and plutonium to supply the worlds electricity, probably until solar or fusion becomes practical. Whatever the risk of a state-of-the-art nuclear power plant, it is certainly safer than a nuclear warhead. And reactor waste presents less of a disposal problem than weapons grade uranium or plutonium. See my post on GREENHOUSE GAS & the ECONOMY for my plan to deal with these problems. . To: W.M. Connolley Hi, I came across the sci.environment resources web page and your article "Was a new Ice Age predicted in the '70's?" You claim "No". But it was. And, strangely enough, the failure to acknowledge this has given much support to those who deny the effect of CO2 and "global warming" today. Just after I saw your article, I read an item in our local paper with the title "Global Warming and other Myths" by B. Fred Singer, professor of environmental science at the University of Virginia and former director of the U.S. Weather Satellite Service. He repeats a claim I have heard before: there can't be much to the idea of global warming from human generated CO2, since the earth warmed more during the period from 1880 to 1950 (when humans released less CO2) than during the period 1950 to present (when we released more CO2). A UW professor of economics made a similar claim in our local paper in 1993. I wrote a letter in rebuttal, which was printed and evolved into my web page-post " CO2 and Global Warming" (environmental section). The textbook I used when teaching geology clearly predicted an "ice age", either a BIG one and/or a LITTLE one. The text is GEOLOGY TODAY, published by CRM (a division of Ziff-Davis Publishing Company). The "author" is a panel (committee?) of 23 Contributing Consultants, all with advanced degrees and from recognized universities or institutes. The Library of Congress number is 72-93822, and it has a Standard Book Number 87665-151-1. My copy is 1973, and chapter 17 is HISTORY of CLIMATE. If you want to have a BIG ice age predicted, just look at Figure 17.14 for the pattern of loess and grassland/forest soils. We are in an interglacial period now and have been for about 10,000 years. Past interglacial periods have lasted just over that length, and the obvious inference is that if the pattern continues, another ice age is due "soon". But without considering the "long range" forecast, but only the "near future", Figure 17.5 predicts a "little ice age" from 1970 to about 2000 (AD). This is from the work of Willy Dansgaard, based on the O16/O18 ratios in the Camp Century ice cores. As my post notes, prediction of the future based on the pattern of the past and without consideration of human activity did predict a cold spell that did not materialize. The "global warming" predictions made at about the same time did not take the expectations from historic patterns as their baseline. The failure of a "Little Ice Age" to materialize since 1970 is the most obvious effect of Global Warming. PS I have a link to the sci.resources page on my web page. ,,,,,,, ____________________ooo__(_O O_)__ooo_________________________ (_) Jim Blair (jeblair@facstaff.wisc.edu) University of Wisconsin, Madison (USA). For a good time, call http://www.execpc.com/~jeblair/ From: JSCHLOER@rzmain.rz.uni-ulm.de (Jan Schloerer) Newsgroups: sci.environment Subject: Re: Ice Age Predictions Date: 24 Oct 1996 17:28:23 GMTOrganization: University of Ulm, Germany jim blair included: > As for the Daansgard Cycles, see the article by Wallace Broecker > in Science 189 p 461, 1975. He tries to combine the cold spell > expected from the historic pattern with the CO2 effect to predict > the resulting actual temperature. Gribbin's claim is that the > 1990 Panel on Climate Change just ignored the historic pattern > when making their predictions. Yes, looking for the true natural climatic baseline makes sense,it's unlikely to be flat. There may well be decades-to-centuries long regional oscillations. Sadly, these are hard to track down [1]. Broecker based his 1975 hunch on the Camp Century ice core [2]. Meanwhile it turned out that the stories told by other Greenlandice cores differ from what Camp Century says. Stable oxygen isotopes aren't that good at recording small (decadal-to-century scale) temperature changes; some confounders are local temperature variations, changes of seasonal patterns of precipitation, or shifts in atmospheric circulation (e.g., storm tracks) [3]. The notion of oscillations or fluctuations involving the North Atlantic is still around [4]. Again, these are hard to pin down, given the dearth of sufficiently long and detailed records.By the way, don't just stare at the North Atlantic. The recent climatic history of much of the Pacific or of Antarctica, for instance, aren't too well known and may hold surprises. Minor nit: Dansgaard-Oeschger cycles usually means millennial-scale oscillations during the last glaciation. These _are_ real :) [1] William James Burroughs, Weather Cycles: Real or Imaginary ? Cambridge University Press 1992 [2] S.J.Johnsen, W.Dansgaard, H.B.Clausen, C.C.Langway, Climatic oscillations 1200-2000 AD. Nature 227 (1970), 482-483 Wallace S. Broecker, Climatic change: are we on the brink of a pronounced global warming ? Science 189 (1975), 460-463 [3] Wallace S. Broecker, Global warming on trial. Natural History 101, 4 (April 1992), 6-14 [tells, among others, how Broecker's beautiful theory built on the Camp Century core was slain by ugly facts. Nice, if a little dated: no tropospheric aerosols yet, e.g.] [4] Michael E. Schlesinger & Navin Ramankutty, An oscillation in the global climate system of period 65-70 years. Nature 367 (1994), 723-726 Jan Schloererjschloer@rzmain.rz.uni-ulm.de Hi, The oxygen isotope data is not critical to establishing the history of climate. There many ways to know that the climate has gone through extended (50-100 year) periods of relatively warm or relatively cold weather: everything from written records to the times of grape harvests. And looking at the general pattern, I think it likely that we were due for a "cold spell" starting about 1950-70, to last until around 2000. But it did not happen. In July 1997, Steve Conover, Sr. wrote: > Or one could ask which way the temperature is supposed to go when > the climate "changes." Twenty years ago, climatologist and > eco-doomster Stephen Schneider warned of a global cooling > catastrophe. Now he warns of a global warming catastrophe. My > how quickly things can change in 0.00000001 eons. > > (Check out Ronald Bailey's book, _Eco Scam: The False Prophets of > Ecological Apocalypse_.) > > --Steve. Hi, Glad to see a reference to the idea that 20 years ago cooling was predicted. I have claimed this, but could not convince some people. See also Science Dec 10,1976, Science Digest Feb 1973, Christian Science Monitor Aug 27, 1974, Newsweek April 28, 1975 and New York Times Sept 14, 1975 and May 21, 1975. Projections of the past history of climate made in the 1970's indicated that the earth was due for a cool period until about the year 2000. But it hasn't happened. Why not? Well it was offset by the warming effect of the CO2 is my suggestion. But this is not something to take comfort in (so to speak): see my web page files on CO2 (and the figures!)in the Environment section of my web page. -- ,,,,,,, _______________ooo___( O O )___ooo_______________ (_) jim blair (jeblair@facstaff.wisc.edu) For a good time call http://www.geocities.com/capitolhill/4834 This from tobis@scram.ssec.wisc.edu (Michael Tobis): No, sorry, it's basic, well-understood physics. : Equilibrium is never reached if : CO2 and other GHGs are continually introduced. Equilibrium only exists : in the models not in the real world. Energy is conserved. The thermal time constant of the atmosphere is a few weeks. The time constant of the forcing is of the order of a few decades. It's perfectly reasonable to treat the atmosphere as equilibrated. The rate of change of the composition of the atmosphere is not a significant term in the radiative balance. Grumbine's description clearly describes the basic radiative physics of the atmosphere. While Hales is absurdly off-base in saying that Grumbine's description is wrong, he still could be seen to have a real point. There is a first order problem in ignoring the heat capacity of the ocean. Some part of the radiative balance may be going to overcome the much larger thermal inertia of the ocean. If the ocean is treated as part of the climate system it indeed may not have caught up yet. To the extent that this is true, there is a lag between the forcing and the system response. This is very important in practice as it means that we are already committed to climate change that has not yet occurred. Even if accumulation stopped, the ocean would continue to warm up for some decades, gradually reducing that term in the radiative balance, and in turn causing further heating in the lower atmosphere to restore equilibrium. In other words, the level of climate change we see now is roughly equivalent to that we already committed to some twenty years ago. In summary, the atmosphere is fairly treated as in equilibrium, and in exactly the way Grumbine described it, but the atmosphere-ocean system is not. ..... mt Steven Hales wrote: This is where you are absolutely wrong. Equilibrium is never reached if > CO2 and other GHGs are continually introduced. Equilibrium only exists > in the models not in the real world.. Hi, I would like to introduce the term "steady state". It is a system not exactly "at equilibrium", but changing in a way that most of the subsystems within it are in (or near) equilibrium with the (changing) conditions of the moment. I think the earth is never at equilibrium, but is moving towards equilibrium in a steady state. We will not be "in equilibrium" until "the end of time". -- ,,,,,,, _______________ooo___( O O )___ooo_______________ (_) jim blair (jeblair@facstaff.wisc.edu) For a good time call http://www.geocities.com/capitolhill/4834 Steven Hales wrote: : > The problem with the climate debate today is that it has become : > politicized. ... : Hi, : Yes it has. But I am confused about the politics of it. : Generally the Right/Conservaitves deny global climate change, but they : support nuclear power. Generally the Left/liberals recognize global : climate change, but they oppose nuclear power. : But if the need to reduce CO2 emission is recognized, nuclear power will : get a BIG boost: today, there is really no alternative to nuclear : electric power if CO2 is to drastically reduced. What is going on here? ---jeb From: tobis@scram.ssec.wisc.edu (Michael Tobis)21 Jul 1997 Organization: Atmospheric Oceanic and Space Sciences It's even wierder. Nuclear power means centralization and strong effective regulation, typically acceptable to the left and anathema to the right. On the other hand, solar, wind and small hydro are rugged individualist solutions that defeat centralization. It really does seem that both sides have this one backwards! I conclude that most people are more concerned with style than with substance. mt