WC Archive

One of the earliest public discussions of abrupt climate change (also called "whiplash ice ages") came from Dr. William Calvin's 1998 article in the Atlantic Monthly, "The Great Climate Flip-Flop." Calvin, a neurophysiologist who specializes in the evolution of the human brain, spent years studying the relationship between global climate and neural evolution. His article spelled out in clear detail the mechanism of global warming leading to a rapid-onset ice age.

He also discussed how to prevent it:

We are near the end of a warm period in any event; ice ages return even without human influences on climate. The last warm period abruptly terminated 13,000 years after the abrupt warming that initiated it, and we've already gone 15,000 years from a similar starting point. But we may be able to do something to delay an abrupt cooling.

Do something? This tends to stagger the imagination, immediately conjuring up visions of terraforming on a science-fiction scale — and so we shake our heads and say, "Better to fight global warming by consuming less," and so forth.

Surprisingly, it may prove possible to prevent flip-flops in the climate — even by means of low-tech schemes. Keeping the present climate from falling back into the low state will in any case be a lot easier than trying to reverse such a change after it has occurred. Were fjord floods causing flushing to fail, because the downwelling sites were fairly close to the fjords, it is obvious that we could solve the problem. All we would need to do is open a channel through the ice dam with explosives before dangerous levels of water built up.

Timing could be everything, given the delayed effects from inch-per-second circulation patterns, but that, too, potentially has a low-tech solution: build dams across the major fjord systems and hold back the meltwater at critical times. Or divert eastern-Greenland meltwater to the less sensitive north and west coasts.

Fortunately, big parallel computers have proved useful for both global climate modeling and detailed modeling of ocean circulation. They even show the flips. Computer models might not yet be able to predict what will happen if we tamper with downwelling sites, but this problem doesn't seem insoluble. We need more well-trained people, bigger computers, more coring of the ocean floor and silted-up lakes, more ships to drag instrument packages through the depths, more instrumented buoys to study critical sites in detail, more satellites measuring regional variations in the sea surface, and perhaps some small-scale trial runs of interventions.

It would be especially nice to see another dozen major groups of scientists doing climate simulations, discovering the intervention mistakes as quickly as possible and learning from them. Medieval cathedral builders learned from their design mistakes over the centuries, and their undertakings were a far larger drain on the economic resources and people power of their day than anything yet discussed for stabilizing the climate in the twenty-first century. We may not have centuries to spare, but any economy in which two percent of the population produces all the food, as is the case in the United States today, has lots of resources and many options for reordering priorities.

Calvin does not underplay the seriousness of such an endeavor. He's talking about geophysical system engineering on a scale never before consciously done, and with an understanding of the staggering complexity of Earth's environment that is growing but still crude. But if we come to believe that an abrupt climate change scenario is not just plausible, but highly likely, what other choices do we have?

Is it better to take the cautious approach if you know that it won't be enough to stave off disaster, or to take the reckless approach that may stop the immediate threat but may well lead to unknown (and potentially greater) problems down the road?

This question comes up again and again. WorldChanging ally Arthur P. Smith, editor of the terrific web resource SciScoop.com, sent us a provocative essay for inclusion on WorldChanging. In it, he looks at what our options are if we need to reduce greenhouse gasses quickly and effectively with current (or near-term available) technologies. We're sure that some readers will disagree with a few of Arthur's proposals (Alex, for example, strongly disputes the utility of nuclear breeder reactors), but the essay is well-worth reading and thinking about.

How much is a blue sky worth?

Arthur P. Smith

Human-caused global warming is real, and the problem is getting more urgent. Recently at sciscoop I provided a detailed review of an important book covering basically all the potential solutions to the greenhouse gas problem: Innovative Energy Strategies for CO2 Stabilization. Two basic conclusions: 1. this is a huge problem, bigger than anything we've ever tackled collectively before. 2. there's hope, in the form of technical and policy strategies that have some chance of working.

Read the review (or the book itself) if you want details; what follows is a summary of the possible solutions, and why they might work.

The most interesting and possibly least expensive strategy to mitigate the effects of warming is based on recognizing that our effect on the climate is something we can control through deliberately messing with the atmosphere. In particular, small particles (aerosols) in the upper atmosphere reflect back sunlight before it has a chance to be trapped by CO2. There seem to be a number of practical ways to do this, and even some experiments along these lines.

Unfortunately, this would turn the daytime sky white, and there may be other side-effects.

Similar "macro-engineering" concepts were recently discussed at the widely mocked climate change management conference in Cambridge, England. Solutions discussed there included underground burying of liquefied carbon dioxide; disposal in the sea; fertilising its absorption by marine algae; reflecting the sun's rays in the atmosphere; and stabilizing sea-level rise.

These "mitigation strategies" could at least delay the onset of severe world climate change, but they don't address the fundamental problem: the world's ever-increasing energy needs, and continued reliance on fossil fuels. Which is what the rest of the "Innovative Strategies" book was about.

First, the solutions that don't work, or won't be able to do enough by 2050 to make much difference:

• Energy efficiency - a delaying tactic. It doesn't address the fundemantal need to replace coal and oil. Efficiency could reduce by a factor of two or three the ultimate scale of renewable resources needed, but it can't be the main solution.
• Wind and ground solar: intermittency and geographic dependence of the resource requires energy storage and long-distance transmission, if these are to provide a substantial base-load level of power. They also require a lot of land (or ocean) surface. Costs for storage, transmission, and land may dwarf the already high costs for the generating components; costs for wind are better than for solar right now, but wind is not expandable to meet even the lowest estimates of world energy needs.
• Hydro: it can expand somewhat, but expensively, and not enough to meet more than a few percent of needs.
• Once-through fission: expensive with current safety reviews; Uranium fuel is limited; weapons concerns and waste disposal need to be addressed (weapons concerns are even more of an issue with breeders though).
• Fusion: it won't be ready for large-scale use by 2050. But "early in the third millenium" it should be available.

Yes all of the above are factors that will help, but even all together, they're not sufficient to solve the problem of replacing fossil fuels to the degree expected necessary by 2050.

So what is there that can work on a large enough scale, and has the potential of making a serious dent in the energy supply problem by 2050?

• Bio-fuels. Wood and waste burning already supplies as much energy to the world as hydro power; since CO2 released during burning of bio-fuels is equal to what the plants absorbed from the atmosphere in the first place, this can help mitigate CO2 buildup. Aside from the soot and other chemicals from incomplete burning that may have nasty side-effects, one problem with this is the vast tracts of land that will have to be devoted to energy production; millions of square miles, worldwide. But the potential scale is there for this to work.

• Nuclear breeder reactors. Fuel reprocessing makes thousands of times more energy available than the once-through cycle would, and can actually reduce the final nuclear waste levels. Diversion of reprocessed plutonium is a major security hazard though, particularly if we are building thousands of new reactors to meet world energy demand.

• Solar power collected in space and beamed to the ground. This avoids the transmission and storage problems for ground solar, and can make better use of the capital investment in photovoltaics (a factor of 5-8 times as much solar energy received by each panel every year). Launch costs and space component and construction costs for a system on this scale are largely unknown; there are at least no physical obstacles, and this is by far the most scalable of all
  energy options.
  

Repeating the summary from the sciscoop article:

(1) Human-generated CO2 and the associated global warming is a big problem for the coming century, although there are some engineering strategies that could (with other side-effects) mitigate it.

(2) We're going to be running out of fossil fuels anyway in the next few centuries; without alternatives, global economic prosperity will be endangered much sooner than that.

(3) Depending on how far efficiency improvements can get us, the mid-century energy requirement from non-fossil sources is between 9 and 30 TW(thermal), or 3 - 10 TW (electric), year-round.

(4) No current renewable technology can provide that power level for less than about $10 trillion in capital investment.

(5) The best plan seems to be an adaptive one: introduce a carbon tax and technology incentives of all sorts for the renewable options, and then adjust both taxes and incentives in response to changing assessments of CO2 damage and non-fossil technological promise.

(6) Wind may be ready for large scale installation; however investments are needed in energy storage and transmission technologies to make it really practical. Biofuels are already in large-scale use: R&D investments to improve their efficiencies, perhaps including genetically engineered crops, should be supported. Solar is a little further away, but R&D there should be strengthened because of the huge potential.

(7) Nuclear fission will be around - we need to decide whether to try to make it a big part, or a small part, of our energy future (i.e. choosing between once-through and breeder fuel cycles).

(8) Fusion likely won't help by mid-century. But the long-term payoff may be large; we should continue to invest moderately in the technology.

(9) Space solar power, whether or not on the Moon, has enormous theoretical potential. Technology incentives to prove its capabilities seem warranted - investments and demonstration projects at least for photovoltaic capabilities, light-weight space construction, space launch, and wireless power transmission. all seem well justified by this and spinoff applications.

Massive threats. Massive challenges. Massive solutions. Difficult choices.