RealClimate logo


Technical Note: Sorry for any recent performance issues. We are working on it.

Hit the brakes hard

Filed under: — group @ 29 April 2009 - (Español)

There is a climate splash in Nature this week, including a cover showing a tera-tonne weight, presumably meant to be made of carbon (could it be graphite?), dangling by a thread over the planet, and containing two new articles (Allen et al and Meinshausen et al), a “News & Views” piece written by two of us, and a couple commentaries urging us to “prepare to adapt to at least 4° C” and to think about what the worst case scenario (at 1000 ppm CO2) might look like.

At the heart of it are the two papers which calculate the odds of exceeding a predefined threshold of 2°C as a function of CO2 emissions. Both find that the most directly relevant quantity is the total amount of CO2 ultimately released, rather than a target atmospheric CO2 concentration or emission rate. This is an extremely useful result, giving us a clear statement of how our policy goals should be framed. We have a total emission quota; if we keep going now, we will have to cut back more quickly later.

There is uncertainty in the climate sensitivity of the Earth and in the response of the carbon cycle, and the papers are extremely useful in the way that they propagate these uncertainties to the probabilities of different amounts of warming. Just looking at the median model results, many people conclude that a moderately optimistic but not terribly aggressive scenario such as IPCC B1 would avoid 2°C warming relative to pre-industrial. But when you take into account the uncertainty, you find that there is a disturbingly high likelihood (roughly even odds) that it won’t.

Schmidt and Archer N and V figureBoth papers come to the same broad conclusion, summarized in our figure, that unless humankind puts on the brakes very quickly and aggressively (i.e. global reductions of 80% by 2050), we face a high probability of driving climate beyond a 2°C threshold taken by both studies as a “danger limit”. Comparing the two papers is obscured by the different units; mass of carbon versus mass of CO2 (moles, anyone? Is there a chemist in the house?). But chugging through the math, we find the papers to be broadly consistent. Both papers conclude that humankind is already about half-way toward releasing enough carbon to probably reach 2°C, and that most of the fossil fuel carbon (the coal, in particular) will have to remain in the ground.

We feel compelled to note that even a “moderate” warming of 2°C stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations. Global warming of 2°C would leave the Earth warmer than it has been in millions of years, a disruption of climate conditions that have been stable for longer than the history of human agriculture. Given the drought that already afflicts Australia, the crumbling of the sea ice in the Arctic, and the increasing storm damage after only 0.8°C of warming so far, calling 2°C a danger limit seems to us pretty cavalier.

Also, there are dangers to CO2 emission other than the peak, such as the long tail of the CO2 perturbation which will dominate the ultimate sea level response, and the acidification of the ocean. A building may be safe from earthquakes but if it is susceptible to fires it is still considered unsafe.

The sorts of emission cuts that are required are technologically feasible, if we were to build wind farms instead of coal plants, an integrated regional or global electrical power grid, and undertake a crash program in energy efficiency. But getting everybody to agree to this is the discouraging part. The commentary by Parry et al advises us to prepare to adapt to climate changes of at least 4°C, even though they recognize that it may not be possible to buy our way out of most of the damage (to natural systems, for example, including the irreversible loss of many plant and animal species). Anyway, how does one “adapt” to a train wreck? There is also the fairness issue, in that the beneficiaries of fossil energy (rich countries today) are not the ones who pay the costs (less-rich countries decades from now). We wonder why we were not advised to prepare to adapt to crash curtailing CO2 emissions, which sounds to us considerably less frightening.

p.s. For our German-speaking readers: Stefan’s commentary on the KlimaLounge blog.


604 Responses to “Hit the brakes hard”

  1. 151
    Doug Bostrom says:

    #131 Jim:
    “Anne van der Bom, you provided a forthright analysis of the cost of wind power so I do not have to look further. It is $0.08 over market expectations. Oh well, that is for Denmark which might be a more orderly place to get things like this done.

    We all have our idea of what is politically possible. In the USA I think this would be difficult at best. ”

    I run a telecomms network out in Hawaii. This gives me an interesting perspective on affordability of electricity; perhaps I may even say doing business where we are located gives us a glimpse of the future in other places.

    Where most of our gear is located electricity for residential use is presently $0.30/kWh. Our expectations about costs are stretched, let’s say.

    But guess what? We still use electricity, businesses find it possible to make money, lights burn in homes when needed, in fact all sorts of things prove possible in spite of the dour predictions of Cassandras in other places more amenable to needless consumption. Not so remarkably we’re much more likely to notice parasitic drains, wasteful lighting schemes and other things that seem rather stupid once they come to one’s attention. I work from the mainland and when my colleagues from the Islands visit it is rare not to hear wry remarks on the waste they see here.

    It seems the price of vital products such as electricity turns out to be highly inelastic. Recently costs in Hawaii spiked to $0.40/kWh. Guess what? Life was still easily possible, though some of us were prodded to notice and eliminate even more waste. Meanwhile many other enterprises still seemed to have money and presumably profit available to sacrifice so we still saw parking lots illuminated throughout the night long after customers have gone home, etc. There’s obviously room for improved habits even with Hawaii’s astronomically high rates, leaving us to conclude that tolerance for even higher rates is also available.

    I’d say Hawaiian electrical consumers make a nice lab population to help identify and then dismiss fearmongering about economic collapse due to the possibility we may be forced to fully account for our energy habits.

  2. 152
    Peter Williams says:

    P.S. Thanks for the post. I realize I was a bit cranky-pants this AM and last PM. Keep it up. Great work and – whew! – do we have a mountain of more work ahead of us if we want to survive the century….

  3. 153
    David B. Benson says:

    Wilmot McCutchen (141) — Anaeobic digestion of any biomass produces biogas which can easily be separated into methane and acid gas. The methane, with a little effort, can be of sufficiently high quality to introduce into the natural gas pipelines; this is being done at several locations in Europe and even the U.S.

    Pyrolysis of any dry biomass produces pyrolysis oil, similar to #2 heating oil, and biochar. Biochar can be made as low grade as bituminous coal, but easily can be as high as 96% carbon, 4% ash.

    An increasingly used method is torrefication (a form of slow pyrolysis) of woody biomass; in some localities the result is marketed (to utility companies) under the name of “biocoal”. Another inceasingly used method is simply to co-fire dry biomass with fossil coal but there is now a Southern Company project to refit two coal reactors into forestry waste reactors. There are other, purpose-built projects producing building heat or electricity from forestry wastes; some as CHP.

    Biodiesel from Jatropha is the preferred route in South Asia and some countries in Southeast Asia. The largest project I know of is a million hectare plantation in one state of India. Brazilians meet much of their motor fuel needs with ethanol from sugarcane; on a smaller scale also in India.

    Checking
    http://www.icis.com/blogs/biofuels/
    once or twice a week enables one to keep up with the fast developments in biofuels.

  4. 154
    Shauna says:

    #56: As an addition to your list of the non-positives of nuclear energy, it is my understanding that the CO2 generated through the enrichment processes of uranium (and mining and transportation) is roughly equivalent to the CO2 released by burning coal.

    #145: Thank you for bringing up geothermal and thin film PV. In terms of cradle to grave, geothermal has a similar footprint and payback as wind or water power, and similar ecological impacts, depending on the method, the installation, and the decommissioning (long life span though, with appropriate upkeep!). Thin film has certainly boosted panel efficiency and decreased the production “costs,” in terms of sustainability. Imagine if we’d have focused R&D on solar panel technologies since its inception in the 1880′s?

    Undoubtedly, solar is a direction we have to go with energy. Small-scale solar, which can essentially be done anywhere at mid and lower latitudes, has fairly limited effects on ecological habitats (though I’d like to see better resource extraction for silicon, copper, etc), concentrates resource needs to a local level, harnesses an “unlimited” resource, is a great compliment to other renewables, and once operational has no emission footprint. Since I am not involved in the energy market, I’ll keep my fingers crossed for a renewable economy.

  5. 155
    Phil Scadden says:

    #64 Anne. The book does the comparisons for “moderately affluent” but also states the average figure (24kWh/p/d). He also notes the difference between his “moderate affluent” 195kWh/p/d and the average which is 125kWh/p/d. The energy plans are on the basis of actual energy use. And electrical car efficiency was one place he noted that you can make big gains. The point of “affluent” I assume was to show where to make a BIG difference.

    And yes, I have studied the numbers VERY closely. I have done the numbers for New Zealand but on basis of the average NZer not the moderately affluent and used actual studies of potential where available. I have put the whole document up on http://www.inference.phy.cam.ac.uk/wiki/sustainable/en/index.php/NZ (MacKay’s wiki for country calculations). NZ is renewable rich but numbers are still cause for a big swallow. 50% of our consumer energy is from oil – we have to banish the nimbys to get off oil.

  6. 156

    In all this discussion, I’d like to explore one data point.

    Question: When/if the polar ice caps completely melt, how much higher will the oceans be?

    Paul Blanchen and three other researchers did an analysis of Xcerat Park in Mexico. The report (and an abstract and a short interview with Blanchen) are in NATURE, pages 803 and 881, V458 (4/16/09).

    Their focus was the sea rise change circa 121,000 years ago. They measured that change (presumably when all polar ice had melted) at about 7 feet.

    Elsewhere on this site I’ve seen statements that the rise might be as much as 35 feet. 7 feet MIGHT be sustainable; 35 feet clearly is not.

    Does 7 feet seem reasonably accurate, or will it be more (assuming the polar ice completely melts)?

  7. 157

    On another part of the puzzle. John Holdren is quoted in the same issue of NATURE (on page 819) as saying a $100 tax on carbon will cause the price of gas to rise by 30c. That sounds affordable.

  8. 158
    Phil Scadden says:

    Bird deaths from wind turbines. Also from MacKay’s book.
    30,000 bird deaths in Denmark from windmills. Hmm – except that traffic kills 1 million in Denmark and cats in UK kill 55 million. A little perspective needed I think

  9. 159
    Larry says:

    I would like to take this discussion back to the themes in the title of this blog article and its final sentence:

    “Hit the brakes hard”

    … and …

    “We wonder why we were not advised to prepare to adapt to crash curtailing CO2 emissions which sounds to us considerably less frightening” (than the “train wreck” of 4oC warming).”

    Unfortunately, the only description of the meaning of hitting the brakes hard is a conclusion drawn from the Meinshausen et al. and Allen et al. papers that “put(ting) on the brakes very quickly and aggressively” means a reduction in global CO2 emissions of 80% by 2050. To me that seems to be not quick or aggressive, but a soft foot on the pedal. Especially so when a peak in emissions as late as 2020 is what many now advocate and is so far the best (but I think inadequate) policy being visibly advocated to go along with a 2050 reduction target.

    I am grateful that this article identifies the perils of even a 2oC global increase, calling it “a danger limit (that) seems to us pretty cavalier” and raising the predicament of the “the long tail of CO2 perturbation.” But these observations contradict the belief that an 80% reduction by 2050 is truly “put(ting) on the brakes quickly and aggressively.” I wish that this contradiction had been explored in the article.

    My belief is that “hitting the brakes hard” should mean an interim global cap at the present rate of fossil fuel production, as soon after conclusion of the December Copenhagen conference that national ratifications can be secured. End further growth in emissions from those sources, pronto. Why not a peak in emissions in 2010 if at all possible and 2012 at the latest, ten or eight years ahead of what is presently contemplated? Developed nations take an immediate small cut in imports, to allow developing ones some increased use. And from that point begin a steep annual reduction of fossil fuel production, year by year. That is hitting the brakes hard. That is quick and aggressive action. And I believe it is vital. Why not advocate this? Even if it may not ultimately be achieved politically, it would help change the political dynamic.

    In their commentary (“The Exit Strategy”) in the current Nature edition, Allen et al. (collectively most of the authors of both the above Allen et al. and Meinshausen et al. papers) say:

    ” … if total emission are limited, and we are not sure exactly what the limit is (but evidence suggests it may not be too far away), then there is a good chance we will find out too late that we have exceeded it.”

    We must take a pass on that so-called “good chance” at all costs, I believe.

    Finally, a question for David and Gavin: McNeil & Matear (2008, PNAS 2Dec08, “Southern Ocean acidification: A tipping at 450-ppm atmospheric CO2″) suggest that by 2030 and no later than 2038 seasonal aragonite undersaturation is likely to disrupt the Southern Ocean ecosystem, due to key forms of zooplankton being unable to form shells. These zooplankton are also a significant carbon sink. Has this possibility been taken into account in models generally, and the ones in the above paper in particular?

  10. 160

    #150 Doug Bostrom,

    I hear you and completely agree that we can and should dramatically reduce our consumption. (I also lived on an island, that being Bermuda, for two years. The only water we had was collected on our own roof, mostly in the winter. For a family from the USA, that changed things like you would never believe. Electric power was generated by using imported fuel, so it was also used very carefully. Yes it can be done.)

    But I think the right policy needs to include price pressure that would help balance the choices away from coal, where we would honestly admit that this cost would go to the public, not some imaginary evil coal guy. It must also include making available to the public the means to cut use of fossil fuel. I mean cut it dramatically, like 60% to 70%. My mix of cuts would focus on personal transportation, freight transportation, and power generation and it would meet more than half way the efforts of people that are trying to reduce waste.

    As I recall from visits to Hawaii, wasteful life practices are much reduced compared to the USA, and this is because fuel has always been a costly thing there.

  11. 161
    James says:

    (Sigh) Seems that even here, scientific ignorance & innumeracy are rife. Just a few comments:

    Jim Bullis, Miastrada Co. Says (30 April 2009 at 1:30 PM):

    “There is no such thing as an electric motor that is not coupled to a heat engine.”

    Photovoltaic cells are not heat engines. The turbines in a hydroelectric plant are not heat engines. I suppose wind turbines might be, in the sense that the whole atmosphere is a heat engine, but Carnot efficiency is not very relevant to them. There are people who live off-the-grid, yet run appliances having electric motors with no heat engine connected.

    Mark Cunnington Says (30 April 2009 at 1:45 PM):

    “Unless, through incentives, it becomes economical to install solar panels on your roof; then you’d have instantly opened up a workforce of 100 million homeowners who would each take care of installing solar panels on their own roof. Of course, you’d need contractors to do the work, and these could be the currently unemployed construction workers. Then you wouldn’t have to worry about all the hassles of opening up vast ares of deserts to make solar farms. The only tricky part would be supplying that many solar panels.”

    A bit of sloppy thinking there: 100 million homeowners to do the work, but it has to be done by contractors? Does not compute :-)

    Beyond that, where are all those solar panels going to come from? Fallacies of scale again. PV panels are currently around $2/watt (you can look this stuff up, you know). Price is the same whether they’re put on roofs, or some central power plant. How are those panels going to be made? Right now there’s a certain production capacity: so many watts per year. Ramping that up significantly requires years of lead time to build factories & equipment… I’ve never seen a study that didn’t betray an obvious bias, but it doesn’t seem unreasonable to think that the time & cost to do all this, and get say 100 GWatts of solar panels out there generating power, is going to be much different from that needed to build 100 nuclear plants. And again, my position is that we ought to start doing both right now.

    ccpo Says (30 April 2009 at 2:00 PM):

    “To my knowledge, not one privately funded nuclear plant currently in operation on the planet.”

    Huh? About 100 of them in the US alone.

    “Cost estimates rising towards 12 billion each, or 4.8 trillion for the US alone (assuming only 400 needed.”

    Whose cost estimates are those? The ones the anti-nuclear folks come up with, every time someone does a cost estimate on solar/wind power? It was only a few months ago that people were quoting $5 billion/plant – then I pointed out that equivalent solar would run at least $6 billion…

    “Time frame: decades. (I.e., too late.)”

    Why? Get rid of the legal road blocks, and the actual construction time is much less, especially since (as pointed out elsewhere) we happen to have a bunch of unemployed construction workers around.

    “$5,000 for every household in the US to retrofit and/or add solar and/or heat pumps and/or wind turbines in a community-based program using local materials…”

    Look, just go to Google, do a search on home solar power systems, and tell me you can find one for that price that generates close to what the average house uses. Here’s prices from a local to me dealer: http://www.nevadasolar.com/catalog.htm Double that $5000, and then some, for even a small 2KW system.

    SecularAnimist Says (30 April 2009 at 2:05 PM):

    “The same is true of the materials needed to build nuclear power plants.

    But Mark was talking about mining uranium.”

    I don’t quite see the point. Isn’t all mining pretty much the same, in terms of cost & environmental effects, regardless of what’s being mined? It’s the mass of ore that needs to be dug (and whether it’s surface or underground) that’s the major factor. The uranium needed to power the plant is going to be a small fraction of the mass of the plant, or the equivalent solar/wind equipment.

  12. 162
    James says:

    Doug Bostrom Says (30 April 2009 at 4:07 PM):

    “I run a telecomms network out in Hawaii. This gives me an interesting perspective on affordability of electricity; perhaps I may even say doing business where we are located gives us a glimpse of the future in other places.”

    In that case, perhaps you could answer a couple of somewhat off-topic questions. First, there’s a geothermal plant just up the road from me that’s been cranking out 100 MWatts or so for years, from one not remarkably large geothermal area (haven’t been any active volcanos in the immediate neighborhood for 100K years at least), and selling it fairly competitively – certainly much less than your 30-40 cents per KWhr. So why in the world isn’t Hawai’i getting all of its electric power from geothermal?

    Second, why not electric cars (once you get the geothermal working), since there really aren’t may places where you can actually drive 100 miles at a stretch?

  13. 163
    David B. Benson says:

    John Burgeson (154) — Ice caps, such as
    http://en.wikipedia.org/wiki/Penny_Ice_Cap
    are too small for appreciable concern. It is the ice sheets, in particular
    http://en.wikipedia.org/wiki/Greenland_ice_sheet
    and
    http://en.wikipedia.org/wiki/West_Antarctic_Ice_Sheet
    which are at risk. During the previous interglacial, the Eemian, temperatures were about 2 K warmer than now and the sea highstand was 4–6 meters higher than the current level, depending upon location measured. The water is thought to be melt from both GIS and WAIS.

  14. 164
    David B. Benson says:

    “Catastrophic Climate Future: Are We That Stupid?”:
    http://www.livescience.com/environment/090429-total-carbon.html
    is another take on this story, one with several quotations from Gavin Schmidt.

  15. 165
    Walt Bennett says:

    I’ve gained access to the current issue of Nature and I will be studying the relevant articles in detail.

    I am encouraged to note that there is robust R&D currently underway which has already yielded practical methods of removing CO2 from the atmosphere. At present, these methods output CO2 which must then be stored, but there is obviously reason to expect that the eventual outputs can be used again as fuels, for example, or perhaps turned into materials which will be easier to store. I envision a day when carbon rich liquid is used to fill in the holes from which oil was once extracted, for example, and of course for the foreseeable future there will be applications (air travel) where fossil fuels are the only viable option.

    So I say it’s quite foreseeable that we will learn how to manage atmospheric CO2 levels, perhaps within the next couple of generations.

    I think we are all agreed that the next 40 years will determine the arc of AGW as concerns the maintainability of the current ecosystem. By any measure we will need a broad array of solutions to get there.

    I am quite encouraged by what I am reading. We are looking at all options, and finding promising ideas worth pursuing.

  16. 166
    EL says:

    63 Hopkins – “Sceptics say that computer models tell us nothing.”

    Mathematical models have been used in decision making for a very long time. If I was to be very technical, even physical theories can be referred to as mathematical models. Biology is also becoming very mathematical and uses models frequently. When skeptics refer to models as silly, they are going against mathematics itself. They could argue that their model is mathematically incorrect, but they would have to show the errors mathematically. They could also argue that the models are not in relation to what is being observed. When a skeptic attacks modeling itself as some do, he or she is going against mathematical knowledge.

    Mark – “Incorrect. Global warming is not a result of over population.”

    Do you actually read these post or use the force? I personally think you just like to argue and “find” reasons to do it. So fine, one could argue that over population of humans increases the effect of global warming. There is more demand on resources that come from forests, and there is more demand for fossil fuel technology.

  17. 167
    Ray Ladbury says:

    Burgie, look here:

    http://pubs.usgs.gov/fs/fs2-00/

  18. 168
    MikeN says:

    An 80% reduction of CO2 emissions takes things back to the level of 1900 or so, when things were much dirtier. This doesn’t sound practical.

    [Response: Or relevant. - gavin]

    On top of that you have other countries increasing their emissions, and they are not going to stop.

    Under your different model scenarios, is there even one that has China not emitting more than the ‘danger limit’?

    On top of that, it looks like based on the IPCC assessment, the A1F1 warmest scenario is the best one.

    http://goklany.org/library/Richer-but-warmer%20RV.pdf

    [Response: How shall it profit a man to gain the whole world, but lose Florida, Bangladesh, the Netherlands, Shanghai, London, Venice, New York....? - gavin]

  19. 169
    co2isnotevil says:

    John,

    Re 154#

    The average temp of the south pole (bottom 15 degrees of latitude) is about -36C and the average for the next 15 degrees is -13C. The corresponding averages for the N pole are about -13C and -6C. The idea that all the ice can melt is preposterous because no amount of warming, natural or otherwise, will drop the average temperatures by enough to completely melt the poles. This is largely because they get little to no sunlight for half of the year. The poles will always freeze in the winter. Minimum ice is when the N pole ice mostly melts at the peak of the summer (about where we have been for thousands of years). BTW, the N pole average at the peak of summer is close to 0C, while the S pole summer average is closer to -20C. The temperature data can be found on the isccp,giss.nasa.gov site. Note how the temperature data is indicative of the asymmetric response of the Earth to energy.

    The reflectivity data is equally revealing. This shows how that even though at perihelion, the Sun is close enough that the average temperature should be about 4C warmer than at aphelion, it’s 4C colder instead. This is a result of dynamic N hemisphere reflectivity from fallen snow. In the S hemisphere, snow falls mostly on the water and doesn’t accumulate to reflect energy. The S polar region is intrinsically colder because the ice is over land and can not be melted from the bottom, thus is always reflecting energy. Note that if the N hemisphere snow becomes a permanent ice pack, the extra reflectivity provides all the ‘amplification’ needed to explain the ice core records, as forced from incident solar energy.

  20. 170
    Jim Bouldin says:

    So I say it’s quite foreseeable that we will learn how to manage atmospheric CO2 levels, perhaps within the next couple of generations.

    We already know how to do that Walt–by not burning fossil fuels. It’s not a question of knowledge. It’s a question of human behavior, economics and politics.

    I am quite encouraged by what I am reading. We are looking at all options, and finding promising ideas worth pursuing.

    I’m not. In fact I’m quite disturbed by it. I see a bunch of people who’d rather pursue technological hail-mary passes than do the hard work of energy conservation, forest conservation, alternative energy development, and general lifestyle changes.

    Particularly disturbing is the commentary piece on the direct sequestration of CO2 from the atmosphere. Supposing that ever gets implemented, what do you think that will do to the incentive to maximize terrestrial ecosystem carbon storage, with it’s many ancillary benefits, or to slowing the burning of fossil fuels? Not to mention the cost of the entire process, or that we have no idea on how to store the stuff.

    I’m starting to see a lot of copping out on the whole issue. Not that it should surprise me, because when push comes to shove, that’s what humans often tend to do when overwhelmed.

  21. 171
    dhogaza says:

    30,000 bird deaths in Denmark from windmills. Hmm – except that traffic kills 1 million in Denmark and cats in UK kill 55 million. A little perspective needed I think

    I hate the spam filter here, it ate my detailed response.

    I’ll try a shorter one.

    This argument is no different than arguing that since we kill millions of rats with poison each year, the shrinking arctic ice cap can’t endanger polar bears. After all, at most it will only kill a few tens of thousands of them if it disappears completely.

    Wind farms do impact sensitive species, such as the lesser prairie chicken. A recent paper in BioScience gave a very glum assessment of this impact on an already extremely endangered bird species. We don’t have 55 million lesser prairie chickens, the fact that cats in the UK kill 55 million house sparrows and starlings doesn’t mean that wind farms can’t harm lesser prairie chickens, ferruginous hawks, and other sensitive species.

    I am not arguing against wind power per se. I am arguing against naive arguments such as the one quoted above, which wind power advocates have been using since the early 1990s when they were bitterly opposing site species inventory and mortality monitoring requirements being proposed as part of the site licensing process.

  22. 172
    Doug Bostrom says:

    #158 Jim:

    Totally agree w/price pressure. What’s sort of perverse where I live (mainland) is that we can (and do) opt in to a billing feature for our electricity that allows us to pay –more– to “green up” our electrical consumption. How about flipping the equation and having customers deriving energy from coal pay more instead? Admittedly there’d have to be some sort of contorted redistribution of money to make that work but the point of course is to bring so-called external costs into view.

    #160 James:

    What I’ve heard is that environmentally sensitive persons have caused such friction on permitting that further development of geothermal has been massively delayed. Better to burn heavy oil for electricity than clear a few acres and poke some holes in the ground, right? What’s really odd about that attitude is the area in question sports little indigenous vegetation, having been previously devastated by the hand of man so it’s hard to make an honest despoliation argument. NIMBY is what’s going on there. It’s true the plant is audible if you’re downwind. I guess the recent and hopefully temporary demise of the interisland ferry is only the latest example of short-circuited reasoning. Thanks, kayakers, let’s keep those jets flying in their very most inefficient mode. I’m sure ExxonMobile thanks you, not to mention automakers who get to duplicate cars on every island. Rant-rant.

    Regarding EV range, seems to me this is largely a perfectionism problem, compounded by dreams of riches by folks with proprietary energy storage technologies. If we’d abandon our perfectionist tendencies and ditch the business plans of visionary technofinanciers, a very large fraction of us could stay in our cars if we insist and commute to work without touching gasoline. Have a commute of under 100 miles? Then why– especially if you have a second car that runs on gas for rare but more demanding trips– do you need an EV with 200+ mile range? On days when I commute via car my round trip distance is about 24 miles. I’m sure I’m hardly alone. Why can’t I buy an EV with a 50 mile range? Why do I have to wait until perfectionists at EPA and elsewhere get their dream car with horrendously expensive and exotic energy storage systems (read as “patented, w/rich royalties”) when I could be quite content with highly recyclable lead-acid batteries, unsexy and boring as they are?

    I’m really not sanguine about our chances of fixing this CO2 thing. CO2 is just being added to an existing atmosphere of unbounded avarice, habitual sloth, dogmatic ideology, intellectual laziness. Why must we be so –human–?

  23. 173
    Hank Roberts says:

    Just for the fun of it:

    > I am encouraged to note
    > robust
    > already yielded practical method
    > there is obviously reason to expect
    > eventual
    > I envision a day
    > of course for the foreseeable future
    > the only viable option.
    > So I say it’s quite foreseeabl
    > perhaps within the next couple of generations.
    > I think we are all agreed
    > as concerns the maintainability
    > the current ecosystem.
    > By any measure
    > a broad array
    > I am quite encouraged
    > looking at all options
    > finding promising ideas worth pursuing.
    ____________________
    “reform waddled”

  24. 174
    Brian Dodge says:

    from DOE pricing for utility sized electric generating plants http://www.eia.doe.gov/oiaf/aeo/assumption/pdf/electricity.pdf#page=3

    costs……………….overnight……….variable…….fixed
    …………………….construction………O&M……….O&M
    ……………………..$/kW…………….$/kWh…….$/kW
    wind…………………1,923.00……….0.00………30.30
    Coal.New+CCS………….3,221.11……….6.17………35.28
    Advanced.nuclear………3,318.00……….0.49………90.02
    IGCC-CCS……………..3,496.00……….4.44………46.12

    solar.thermal…………5,021.00……….0.00………56.78
    photovoltaic………….6,038.00……….0.00………11.68

    Given that Kimberlina(solar thermal) cost about $3000 per kW, and Nanosolar and First Solar claim $1,000 per kW(for the panels), I think that their estimates for these rapidly changing technologies are inflated.
    According to http://www.greentechmedia.com/articles/first-solar-panels-big-with-solarcity-customers-6053.html, Solarcity, “which claimed to be the largest residential installer in the country last year”installs a typical 5kW residential system (panels, controls, etc; no economies of scale) for about $30,000 retail.
    DOE also claims 6 years lead time for nuclear; at a round table discussion with utility CEOs (from a business site I didn’t bookmark and cant find), one of them said jestingly that a new nuclear plant takes 15 years – 5 for design & permitting, 5 for litigation, and 5 for construction.

    “At $1 per million BTU for coal, that is the choice.” Paying only $1/MBTU for coal is sorta like buying your house with an interest only ARM; looks good, but only if you’re pretty nearsighted.

    Obama has discovered steering the ship of state is like steering an ocean liner – things respond slowly but inexorably, and require a long view. Wait ’til he tries correcting our course on the environment.

  25. 175
    Ray Ladbury says:

    Jim Bouldin says in response to Walt: “I see a bunch of people who’d rather pursue technological hail-mary passes than do the hard work of energy conservation, forest conservation, alternative energy development, and general lifestyle changes.”

    It’s not either-or. We’re playing catch-up, and after 2 decades of very effective denialist propaganda, we’re deep in a hole. So, we’ll need to make a Hail Mary or two, and we’ll need to conserve like hell to steal back some of that time we’ve lost. I suspect that our best options are no longer options, and all of us are going to have to agree to unpalatable remedies. But, what choice is there? It is quite literally do or die.

  26. 176

    #160
    Ah sigh, my ignorance is deep and wide, but the atmosphere and indeed the sun are heat engines. The turbine and the PV are just part of the machinery. How do you think the EM waves get kicked off the sun? But really, you are right, who cares?

    My ignorance is that I let this academic point get in the way of the real point which is that every real electric motor when turned on or off will have the effect of causing coal to be burned or not burned.

    If a person owns his own solar array and uses power from it to directly charge his own batteries, there might be a case otherwise, though even here the atmosphere might be better off if the solar power was sold to the utility and the electric car was not purchased. If that person took subsidies or relies on the grid for the storage of daytime power for night time use, it is certain that person’s use of an electric motor ultimately connects to coal use.

    Perhaps I should clarify that in no way would that person continue to drive a conventional car. A well designed hybrid is the baseline assumption.

    One of the tricks of the misleaders is to ask, “Is the electric car is better than the conventional car?” That is the trick question. The straightforward question would be, “How does the electric car compare with the hybrid?” In other words, just stop with the hybrid and sell your solar power. That will be the superior action.

    There is a more superior action however, and that is to build the car to use very little energy. Electric methods can be very helpful in that endeavor. Now the plug-in is redeemable for credits in, uh well, lets just call it self satisfaction.

  27. 177
    Will Denayer says:

    What about this?
    http://www.truthout.org/043009EA
    What do you people think? How important are HFC’s? Shouldn’t we concentrate on CO2? Is this good or bad news?

  28. 178

    Wilmot, way back at the top, you asked about 2C difference, and got some useful paleoclimate links.

    Another perspective, a bit more mundane, that I recently figured out in response to a slightly different question:

    For an arbitrary location (Rome, GA) there are currently 72 days yearly for which a minimum temperature below freezing is normal. A 3.5C increase will eliminate all of them. To a farmer, that’s definitely a very big deal.

    (Of course, not all days are “average,” so it will still freeze there from time to time–just a lot less than in the past.)

  29. 179
    steve says:

    Walt I agree the NIMBY syndrome is an obstacle that is going to be difficult to overcome. As far as long term solutions go I agree with Pete and see the utilization of wave and current energy as a very promising field. The wind may stop blowing and the clouds may hide the sun but the waves just keep going in and out.

  30. 180
    Hank Roberts says:

    Will, that’s hardly even news any longer.
    http://www.epa.gov/ozone/title6/phaseout/hcfc.html
    http://ozone.unep.org/Meeting_Documents/mop/19mop/

    There’s a clearly understood problem — China figured out they could claim carbon credits by building large new HCFC plants and destroying one of the byproducts, and selling the HCFCs for cheap third world air conditioners, and got away with that for some years. They’re busted.

    “Mr. McFarland. Yes. I would like to separate two things.
    One is under the current clean development mechanism, projects,
    HCFC-22 plants that were in operation as of January 1, 2001,
    are allowed to participate under CDM. The current debate is
    about HCFC-22 plants that have come online since then. There is
    a significant issue there. Because of the value of those carbon
    credits, it is possible that the HFC-23 destruction CDM project
    could become the product and the HCFC-22 could become the by-
    product, because the 23 credits would be worth more than the 22
    production.
    So there is a significant issue there, and it is currently
    being debated under the framework convention on climate change
    and how to manage it there, but it is also here is the
    opportunity under the Montreal Protocol to begin to deal with
    the issue by accelerating the phase-out of HCFCs in developing
    countries….

    … Mr. Thornton. Well, there is no law being broken, and that
    is the problem, because there is a disconnect between the
    Montreal Protocol regulating HCFC and the Kyoto regulating HFC,
    and what we are trying to do is to marry the two policies of
    the two treaties together to fast-track HCFC phase-out, at the
    same time cap, reduce, and stop the HFC.”
    http://fdsys.gpo.gov/fdsys/pkg/CHRG-110hhrg11044428/html/CHRG-110hhrg11044428.htm

    No one except, well, a senator and representative or two, are suggesting “global policeman” stuff will happen. Oh, and perhaps agreement from one “rouge” AI
    _________________
    “bring naval” says ReCaptcha

  31. 181
    dhogaza says:

    It’s not either-or. We’re playing catch-up, and after 2 decades of very effective denialist propaganda, we’re deep in a hole. So, we’ll need to make a Hail Mary or two, and we’ll need to conserve like hell to steal back some of that time we’ve lost. I suspect that our best options are no longer options, and all of us are going to have to agree to unpalatable remedies. But, what choice is there? It is quite literally do or die.

    This is key, and ties in to what I’ve said about wind power above.

    One myth that seems to be propagated is that there are energy-generating options that are benign.

    It’s just not true. We have to look the problem in the eye and make educated decisions as to which is less destructive, rather than put forward pablum like “coal is evil, and wind farms don’t do any damage”.

    Wind farms *do* do damage, and indeed a proliferation of them is very likely to lead to the extinction of several species of bird here in the US.

    Maybe that’s a trade-off that’s worthwhile, but lying about the cost is not the right basis for making a decision (attention: Mark). All facts on the table, that’s what we need …

    Energy conservation is still the lowest hanging fruit when we look at the big picture … but it’s probably not enough.

    Anyone arguing for simplistic black-and-whiteness simply isn’t paying attention.

  32. 182

    100 Mark: France recycles nuclear fuel. We recycled nuclear fuel until it was stolen and taken to Israel. I almost took a job designing a nuclear battery for a heart pacemaker using spent fuel as a heat source in 1968. The workers never glowed. The heart pacemaker patients never glowed.

    Did you know that you are radioactive? How do you suppose we can use radioactive carbon to date egyptian mummies? The average natural background radiation in the US is 350 millirems per year. In some places in the US, the natural background radiation is 600 millirems per year. Did you know that coal contains uranium?

  33. 183

    100 Mark: Power plants make the wrong isotope of plutonium for bombs. If you try to make a bomb out of the wrong isotope of plutonium, it doesn’t go boom. It won’t do anything. It takes a very specialized breeder reactor to make bomb plutonium. We are not going to discuss that kind of reactor.

    Yes, there are a lot of politicians who do not have degrees in either physics or nuclear engineering. But their irrational nuclear policies are probably driven by “campaign contributions” from the coal industry.

  34. 184
    Phil Scadden says:

    Okay, so the bird argument is a bit naive, but there is always something for NIMBYs. I’m not saying give a blanket okay to every wind mill and hydro, regardless of bioversity cost, but want to consider the biodiversity losses if we DONT get off fossil fuels? You have to have alternative strategy with mixture of conservation and alternative generation that adds up. Just changing to CFL wont do it. Solar on roof tops wont deliver enough to drive your electric car. By all means give me a strategy for saving Prairie chickens but make sure it isnt at the cost of many others unable to adapt to climate changing this fast.

  35. 185
    co2isnotevil says:

    Doug,

    Re #172

    The whole point of Obama’s carbon tax regime is to “make them go bankrupt” (his quote) referring to those dependent on coal. The first step in this is to make electricity from coal much more expensive because the utilities will need to generate the money to pay the carbon tax (or offsets or whatever you want to call them). This cost will be passed on to the consumer, so those who purchase coal generated electricity will definitely be paying more. Of course, so will those whose electricity comes from natural gas or oil.

    Relative to coal, what we need to address is cleaning it up to minimize acid rain and to minimize real pollutants. Obsessing about CO2 is counter productive, especially since modifying the climate via carbon regulation will surely fail to have any effect on the climate. We can only hope that the worlds economies can handle another multi trillion dollar hit.

  36. 186

    105 Mark: We have nuclear fuel for 5000 years. We can get uranium from the coal ashes. Coal mining requires 100 MILLION times the amount because uranium contains 100 Million times as much energy for a given amount. Nuclear power is 30% CHEAPER than coal. Nuclear is the cheapest and safest way to get electricity. Mark, do you work for the coal industry? I DO NOT work for the nuclear industry.
    See:
    http://www.hyperionpowergeneration.com/why.html

  37. 187
    Steve Reynolds says:

    Jim Bullis: “…but the atmosphere and indeed the sun are heat engines.”

    One totally non heat engine energy source is tidal.

  38. 188
    Thermodynamics Researcher says:

    168. First you say the world was much dirtier in 1900 than it is today, then you say the worst case scenario is the most likely. Now these are mutually contradictory statements. There was no interstate highway system in the United States in 1900, this by itself, would mean that it was a cleaner world back then. Most American’s worked on farms in 1900, there were no petrochemical based fertilizers or pesticides, which only create mountains of soil run-off and mutated insects, to produce the same amount of crop yield. Or actually diminishing crop yields, cropland productivity, as measured by kilograms of cereals per capita year, peaked in 1976, according to Lester R. Brown of the Worldwatch Institute. There was no Sears Building, one building that uses more energy than entire cities, how will “wind farms” meet that demand? Maybe if you gave all the land surface of Australia over to wind farms it would work, otherwise not.

    According to economist Herman Daly:

    “If it requires roughly one-third of the world’s annual production of mineral resources to support that 6% of the world’s population residing in the U.S. at the standard of consumption to which it is thought that the rest of world aspires, then it follows that present resource flows would allow the extension of the U.S. standard to at most 18% of the world’s population, with nothing left over for the other 82%. Without the services of the poor 82%, the “rich” 18% could not possibly maintain their wealth. A considerable share of world resources must be devoted to maintaining the poor 82% at at least subsistence. Consequently even the 18% figure is an overestimate.”

    In fact resource scarcity makes it impossible for even the U.S. to maintain its present level of energy flow.

  39. 189

    “Where do you plan on putting those wind farms? A quick SWAG puts the land area of wind farms to replace the current coal facilities at something like 50,000 square miles.”

    I know others have responded to this, but there are parts of this country with plenty of wind energy that aren’t fragile eco-systems or out in the middle of the ocean. Texas has 268,000 square miles according to an earlier poster. Peak demand is about 60,000 MW, or 223KW per square mile. I live on 0.08 acres and make 1.9KW AC peak. That’s 15,200KW per square mile — and that’s just the residential roofs in a square mile with solar.

  40. 190
    Hank Roberts says:

    Edward, re your “wrong isotope” claim — what’s your source for that?

    I looked, but everything I turned up says the mixture of isotopes gives unpredictable results, so isn’t favored for mass production because it won’t turn out consistent, standard yield, reliable bombs.

    Your home craftsman, though, doesn’t worry so much about this kind of predictability and economy of scale; one-offs work:

    http://www.google.com/search?hl=en&q=plutonium+from+civil+reactors+could+be+used+to+make+bombs

    I’d be delighted to be convinced otherwise, but I have to ask sources.

  41. 191

    154 Shauna: WRONG! Nuclear fission produces LESS CO2 that ANY other source. Nuclear produces LESS CO2 than wind or solar.
    Reference: “Power to Save the World; The Truth About Nuclear Energy” by Gwyneth Cravens, 2007 Finally a truthful book about nuclear power. Gwyneth Cravens is a former anti-nuclear activist.

  42. 192
    David Murray says:

    David MacKay has written a very valuable book on how we should do the calculations to work out what might happen if we hit the brakes hard. He seems to conclude that Britain will have to rely on renewables plus nuclear and or/imported renewables. For the world and North America I think he concludes that renewables alone could keep the system going after we have removed coal from the energy mix. Anne van der Bom, Phill Scadden, Douglas Wise, Jim Bullis and Mike F all comment above directly on MacKay’s results. Some weeks ago I conducted a similar conversation with inter alia Neil Howes and Barry Brook on bravenewclimate at:
    http://bravenewclimate.com/2009/04/11/climbing-mount-improbable/

    Anne writes of MacKay’s treatment of electric cars: ‘Total result is a 12 fold overestimate of the electric energy required to drive Britain’s cars’. That was my conclusion as well (details are at #42 in the bnc discussion for details for Mike F.).

    The treatment of wind energy in the MacKay analysis also caused some concern. Most of MacKay’s conclusions are based on average wind speeds of 6m/s and a consequential on shore wind farm output of 2W/square meter. Using the more realistic wind speeds available the most suitable wind sites changes his results very significantly (because energy output is a function of wind speed cubed). As an example of the results I suggest that with a wind speed of 12 m/s on 3% of the UK surface area there is twice as much wind power available in the UK as calculated using MacKay’s 6m/s over the bulk of the UK land area. (Again there is a more detailed discussion of this issue at #42 in the bnc discussion).

    Uranium resources seem to be understated by MacKay. His calculations are based on known uranium reserves mineable at under $130/ton. As uranium is a very small part of the cost of running a nuclear reactor uranium at much higher prices is still economically usable. With other nuclear technologies and materials there is a very very large potential supply of energy from this source. (Again see #36, in the bnc discussion).

    Based purely on the physics of renewable resources it seems that MacKay’s method shows there is little reason to worry about hitting the brakes hard. The real problem in the MacKay analysis is NIMBYs and Naysayers. He sees them (chapter 18, figure 18.7) reducing potential energy from renewables by about ninety per cent. With that reduction the conclusion that Britain will have to rely on imported renewables and nuclear if it eliminates fossil fuels follows cannot be escaped. That does not mean it cannot hit the brakes – only that it will have to rely on international trade to eliminate fossil fuels from the energy mix.

  43. 193
    Doug Bostrom says:

    #182 Edward:

    Tangentially related to what James asked about geothermal power generation, you forgot to mention that radioactive decay is the source of most geothermal energy, something like 30 terawatts of flux these days according to my Google expertise.

    All the same, unless nuclear plants can be vastly simplified or the quality of assembly and operation enormously improved it’s only a matter of time until we have the next nuclear power generation PR fiasco emerge.

    Why do I say this? Read available incident reports on the relatively few current nuclear plant operating samples. Industry records show that our abilities are highly strained by the complex engineering and fastidious attention required for safe nuclear generating plant construction and operation. A reasonable conclusion from this record is that the way they’re built and run now is unlikely to scale without more big embarrassments.

    Developed nations are –just barely– able to build and maintain these devices with an acceptable (assuming the complete destruction of reactor units at Three Mile Island and Chernoybl are ok) level of catastrophic accidents using the quality of human resources available in the U.S. and Russia, two relatively advanced nations. In point of fact these human resources are lamentably fallible, as industry reports and conspicuous public mistakes indicate.

    To approximate our current coal generation capacity would require increasing the global complement of nuclear plants from some 500 to at least 4,000 units. Could we find a large enough cadre of sufficiently skilled builders and operators to do this? With 500 plants we’ve not quite achieved that feat; what evidence leads us to think we’ll do better with the next 3500 plants than we did with the first 500?

    Worse, global replacement of coal generation with nuclear power will require expanding the geographic range of nuclear power generation to places where human factors can be expected to lead to lower safety levels than we find in the current installation context, where empirical data shows we’re already at or even slightly beyond the limit of what we can expect in terms of consistent quality of construction and operation.

    While inevitably lowering the overall quality level of reactor installations and their operational conditions we will simultaneously expand their number rather enormously. Given the data we have on incident frequency the nearly inescapable conclusions is that we’re going to see more big messes.

    Please do also observe that operators at the time of these incidents large and small are always perfectly confident in their assertions of complete safety and reliability. Let’s not make the mistake of thinking we’re entering some entirely novel, accident-and-incompetence-free permanent era of history– technology may advance but human nature does not seem to follow so quickly, if at all. Based on the results of the utmost skill and dedication we can muster devoted to the first 500 plants, another 3,500 would mean something like 16 additional roughly TMI/Chernoybl-scale problems over the lifespan of those hypothetical plants. Probably even more, given the installation context of many of the imaginary nuclear plants.

    I think a comprehensive (and honest) assessment of alternatives to coal generation will include not only the hypothetical scaling issues of wind and direct solar generation but also will address what we know of the operating record of nuclear plants and what we can expect as we attempt to further scale nuclear power.

    Mind you, I’m not saying I’m against nuclear power. I do however think that many nuclear power proponents have a habit of glossing over the complex and demanding nature of the technology. It’s likely we’ll find many places where reactor-based nuclear power generation is simply not feasible to deploy. Those places are going to require some other solutions.

    Which leads us back to the 30 terawatts of geothermal flux wafting past us right now. How about tapping into some of that? Everybody could enjoy nuclear power and waste disposal is already taken care of…

  44. 194
    Doug Bostrom says:

    The price of brakes: Nobel laureate Paul Krugman writes about the costs of cap-and-trade in the NY Times. His conclusion is that it would be affordable and stimulative, though of course it would add to our cost for electricity. As we’ve seen in Hawaii, people still waste juice even when it’s $0.40/kWh so let’s get started:

    http://www.nytimes.com/2009/05/01/opinion/01krugman.html?_r=1

  45. 195
    John Bartlett says:

    Hi, Someone made the comment above that it is very difficult to convince people of a problem in a world wide system. I think there is a bigger problem here. The philosopher Ken Wilber has suggested that different people have minds developed to different levels. It is only if on’s mind is developed to close to the top of our society that the problem of climate change can even be appreciated. For anyone below that level they just have to be told what to do. How do we get around that?

    There is a case in point – in New Zealand last year there was much interest in government in moving forward with schemes to start dealing with climate change. With the general election last year (2008), the government changed and one of the parties in the new coalition is at too low a level to appreciate the problem and so it has been agreed that the issue with be placed with a committee for the details to be further analysed yet again.

  46. 196
    Ricki (Australia) says:

    Comment 81…..

    Response: I think these, what they would call carbon cycle feedbacks, are a major source of uncertainty. The CO2 slugs they’re talking about are the ones from human emissions only. David

    This is a serious oversight. It is clear to me that the impacts of these feedbacks have a very significant affect on the worst case outcome. If you scientists wish to influence the policy makers you MUST include at least an assessment of these impacts (perhaps as a second layer of information with the usual caveats). The policy makers will actually be expecting this information to be included.

    It seems to me that you are too tied up in what you can substantiate instead of what is a best educated estimate. As an engineer, I would have to include the possibility that a boat may strike the pylon of a bridge, even though it is an unlikely possibility (of course there are some things I would not design for, but I still have to think about them).

    For a bridge, the design philosophy has to be based on the likely worst case outcome tempered with practical economics. For our planet, it should be more conservative, we only have this one at present!

    If these feedbacks are included, what happens to the 1 terratonnes limit? Does this become the recipe for 4C-6C? If so, the worlds governments and the PUBLIC need to know this to make an informed decision about the degree of hardship to take on board now in order to avoid later disaster.

    [Response: These feedbacks are included! as are their uncertainties - gavin]

  47. 197
    Steve Missal says:

    Just a minor request…could some of the overwhelming number of acronyms be fleshed out occasionally for those of us who don’t necessarily know what they stand for…NIMBY,MBTU,HCFC etc etc…although familiar to many who post, I would like to remind all that we are trying to educate a larger readership, and ultimately influence public policy. By a kind of wink/wink insider lingo, we might just do the opposite, looking a bit elitist or worse. Thanks…I otherwise am totally grateful for the contribution RealClimate and the many thoughtful people who post here to the tough job of educating on global warming and climatology in general.

  48. 198
    MikeN says:

    >How shall it profit a man to gain the whole world, but lose Florida, Bangladesh, the Netherlands, Shanghai, London, Venice, New York….?

    From the people who want to save the whole world, but lose large cars, spacious houses, comfortable living…

    [Response: No. Just carbon emissions. You can have as big a solar-powered house as you want. - gavin]

  49. 199
    EL says:

    RE-175

    I do not believe climate change is a do or die state of affairs. The impacts of global warming are certainly undesirable, but most solutions on the table can have undesirable impacts. Some people’s judgment is being clouded with fear, and they do not see the peril of these proposed solutions. When something is created in hurriedness, it bares the resemblance of low quality and ineffective utility; Therefore, we need to take our time to ensure that a proper solution is found and implemented.

    If the justification of fighting global warming is for the sake of humankind, the burden on the underprivileged should be considered before a solution is proclaimed. The concept of a solution, which disregards the impoverished, is completely unethical. Until a solution is found that can work harmoniously with all socio-economic classes, we should continue to research for a solution.

  50. 200
    Gian says:

    Considering the possible risks of 5C rise, the proposed measures seem pretty feeble.
    We must take severe measures if the risk is so great.
    1) Rollback of private vehicular driving and flights (even by the leaders of nations)
    2) Reduction in heated or cooled living space per person.
    3) Reduction in the electricity usage eg vending machines that vend cold drinks, advertising lights, washing machines, computers
    4) Rollback of mechanized agriculture with monocultures of both plants and animals. Mixed farming using human and animal labor is superior and would emit less carbon among other advantages.


Switch to our mobile site