|Chapter 26||Table of Contents||Chapter 28|
Eco 550 — Geoengineering, November 29, 2055
When I was a student, it was not unusual to hear that virtual glasses were going to revolutionize education. Veegees, as they came to be called, were internet connected computers that used the spectacle lens to project information directly into the user-wearer’s eyes. The ‘virtual’ came from the fact the glasses allowed the wearer to manipulate objects only they could see.
What do you tell someone who has the internet group mind mediated by supercomputer playing in their eyes, was the implicit question. The difference between information and knowledge quickly rose to the fore. That is allegedly where the scientific method comes in — and teaching.
By the time I was teaching, veegees were ancient history. Ilens were the latest thing, but too expensive for most. Theoretically CCU was media neutral. In practice, we used anything that worked. The trick in that opennness was that not everybody could afford the latest toys. Some students still used paper.
I walked into my Ecology 550 class that morning with a stack of photocopies of the McNamara preprint. It was a small room that used to be an office. Twenty three students — if they all showed up. The class was more intimate than magisterial.
“You’ll have to excuse me if I am a little abrupt today. I didn’t get much sleep. Doctor Yablonski is in hospital and his wife called me in the middle of the night. I know according to the schedule you’re scheduled to discuss island populations and territory, but something has come up. Something that will affect us all. Those of you who are wired, please take a look at this paper.” I projected the URL on a small screen. “Any of you who are offline or who prefer paper, can take one of these.” I gestured at the stack on the desk beside me.
“We will resume in 15 minutes.”
A few people came forward and took a preprint, some read on a padd, but most of the class got that glassy-eyed look of people surfing with vglasses. One of the students complained that he had stayed up late last night reading up on population dynamics.
“Just read the paper,” I said and started rereading the study myself.
Fifteen minutes later, I stood again and asked, “Are there any questions?”
A young woman in the front row put up her hand. “How could this have happened?” she asked in a plaintive voice.
“You might want to review your notes on the PETM. Look for references to the ‘methane burp,'” I answered.
The woman shook her head. “No, I understand the feedback principle,” she said. “I meant how could humans let this happen?”
I was struck by her earnest innocence. She really didn’t know what had been done. “The major studies, such as James and Johannsen’s ‘The Denial of Climate Disruption in Turn of the Millenium Electronic Media’, amply demonstrate the machinations of corporate interests. If you prefer something more accessible, the autobiography of James Hansen is a fascinating read. Or ‘Carbon War’ by Jeremy Leggett, if you want something from the early days of international negotiations.”
I could see she was not happy with a merely academic answer, so I shifted gears. “Consider the human use of energy over the last one thousand years. We went from a solar economy, driven by manpower and horsepower to a technological civilization driven primarily by external energy sources — steam, electrification, fossil fuels. As far as business was concerned, there was money to be made selling fossil fuels and somebody else could deal with the side effects. Well as it turned out, we all have to deal with the side effects, what an economist would call the externalities.”
I looked directly at the questioning woman. “Besides the texts I mentioned, you might want to take a look at the popular histories of the denier show trials after Hurricane Jacy. ‘Fools, Liars and Fall Guys’ by Ridgeway will give you a good idea of what was happening and it has references to many of the other popularizations.”
I raised my eyes to the whole class. “It is easy to criticize past generations for their profligate ways, the ways which have put us in this ecological trap. It is also useless. I am deeply suspicious of the human tendency to scapegoat. After the West Antarctic Ice Sheet collapsed, the denier trials put a few hundred people in jail, but did nothing for the climate. And don’t forget. We aren’t all that different.”
One of my brighter students in the front row, put up his hand and, without waiting, asked, “What does the McNamara paper tell us that we didn’t know before?”
“Well, two things. First, it has the on site methane readings both in the ocean and in the atmosphere. And second, it surveys the available literature. McNamara et al. authoritatively integrate data from human emissions, satellite observation studies, and field sampling studies to generate an unmistakable conclusion. Large scale feedbacks have kicked in and the climate is now well beyond mitigation policies.”
“So what do we do?”
I was annoyed the guy was asking questions like he was the only person in the room, but it was the right question. “That is what we are going to be focussing on next.”
I looked up to include everyone. “So, today we are going to talk about geoengineering. I will give you a quick outline of the basic concepts, then I would like to get your feedback. It has not been announced yet, but I have been appointed to the United Nations Geo-Engineering TaskForce [UNGETF] charged with investigating our options. I am therefore looking for new ideas and for problems with the old ones.”
“Now, you may think that humanity has no business trying to change the climate, trying to terraform the world as some have put it, but you should realize that in fact we have been changing the climate since at least the beginning of agriculture. It’s just that we have been largely unconscious of the results of our widespread and uncoordinated actions.”
“However, in light of the McNamara paper, I don’t think we now have any choice. If we allow the 12 or 15 degree rise in average global temperatures these massive releases of methane could cause, there would be wholesale disruption of human civilization, possibly extinction.
“Secondly, I would direct your attention to the conclusion of the McNamara paper.” I put it up on the large wall screen at the front of the room:
“Since the establishment of the IPCC in 1987, for a variety of reasons mitigation and adaptation have been the preferred responses to the prospect of dangerous climate change. These policies have failed. The evidence we present in this paper demonstrates that now, the countries of the world have no option but to move to full-fledged large-scale geoengineering, preferably cooperatively.”
“Does anybody have any questions?” I looked around the room and again there was silence. I think the students were mostly in a state of shock.
“Okay. As a first approximation, consider the Earth-Sun system on an astronomical scale, in particular the energy balance.
I don’t want to get too deeply into the climate machine — for that you should take a course in climatology — but a consideration of the energy exchanges may be worthwhile.
Personally, I like setting out the actual numbers involved so that one can have a sense of scale.”
“How much energy does the sun produce?”
It was a rhetorical question and I did not expect or look for an answer. “You can find this data at the NASA/JPL site. The sun converts 4.26*10^9 kg of hydrogen nuclei to helium per second producing 3.83*10^26 watts of energy. That may seem like a lot of matter to be transmuting, but remember the mass of the sun is of the order of 10^30 kg, so it can go on for a long time.”
“The next question is, how much of the sun’s energy strikes the earth?”
Again it was a rhetorical question.
“The earth receives approximately 1.7*10^17 watts of energy continuously. Since the middle of the twentieth century satellites have measured the sun’s energy received at the top of the atmosphere. The term to follow up here is ‘solar constant’. It has remained about 1365 watts/m^2 plus or minus solar cycle wiggle in all that time. Note that there is a slight variation in wavelengths over the solar cycle.”
“The amounts of energy received from tidal forces and from the interior heat of the earth are miniscule compared to the solar component and we will ignore them here.”
“Now what happens to that energy when it strikes the earth?”
“Off the top, approximately 30% is reflected directly back into space. The term to follow up here is ‘albedo’. The rest impinges on the earth where it is converted into heat which drives the climate system — evaporation and precipitation, wind and wave, currents and convection — or is captured by plants in photosynthesis.”
“I would ask you to recall the concept of a black body curve from first year physics. The terms to follow up here are Kirchhoff’s Law and the Stefan-Boltzmann Law. For our purposes, the essential fact is that the Sun’s energy radiates to space in a 6,000 degrees Centrigrade black body curve, while the Earth energy radiates to space in a 14 degrees Centrigrade black body curve. This effective wavelength shift is the underpinning of the greenhouse effect.”
“So how do we change the energy balance?”
Another rhetorical question.
“At a glance, several options are available.”
“First, we could stop some of the sun’s radiation from striking the earth. This is commonly called Solar Radiation Management or SRM. Various methods to achieve this have been proposed.”
“Secondly, we could increase the amount of shortwave radiation that is reflected directly back into space ie. increase the albedo. A variety of methods for doing this have also been proposed.”
“The third geoengineering technique involves managing greenhouse gases, thereby reducing the greenhouse effect. This is commonly called Carbon Dioxide Reduction or CDR.”
“These are the basic options geoengineers have considered. Does anyone see other options?”
It was not a rhetorical question. There was dead silence, at first. Then at the back of the room, a young man put up his hand.
“We could move the earth further away from the sun.”
There were titters throughout the room.
I smiled. “Yes, that would work. I’ll let you devise a way to do that.”
A girl in the front row put up her hand and waited.
I nodded at her.
“Could we lower the temperature of the sun?”
I smiled again. “I’m not sure that would work. How much would you reduce it?”
I put up a black body diagram for the sun.
“I think what we need to do is lower the amplitude of the energy, not slide the curve,
That’s ignoring the little detail that I have no idea how to pull such a trick. Do you?”
She shook her head.
“Okay it is getting close to the hour. For next class, I would like you to do a search for every geoengineering idea you can find. We will put together a catalog. There is a new database on the Eco550 home page where you can add journal article and book references. For now we will skip the popular press. If you are lucky, they may reference the paper they are reporting. For next week, come prepared to do a two minute presentation of one proposal you find interesting.”
I looked around, but there were no questions. “I’ll see you on Friday.”
Excerpted from _The Bottleneck Years_ by H.E. Taylor
For further information see:
A Gentle Introduction.
Last modified February 12, 2013