Basic Science For Global Warming


In order to understand discussions of global warming, you need a few basic scientific facts. I’m stripping them down so they’re easy to remember.

Thermodynamics is an imposing word that means “movement of heat.” Thermodynamics fundamentally establishes boundaries on what chemical reactions can take place and what other kinds of work can be done. Facts derived from thermodynamics cannot be bent or gotten around. Heat is a type of energy, so I’ll use the two words interchangeably here.

Fact #1: Carbon dioxide and water result from the production of energy by burning fossil fuels. In order to make them into something else, energy must be supplied. Not only that, but more energy must be supplied than was produced by burning, sometimes a lot more.

Any claim that a process can turn carbon dioxide back into fuels, or that water can supply hydrogen as a fuel, should be met with the question “Where does the energy come from?” If the answer is non-carbon power, the claim may be worth pursuing. If the claim says nothing about energy sources, more information is needed.

Fact #2: Separating something from a mixture requires energy. The lower the concentration, the more energy is required.

Carbon dioxide is about 400 parts per million in the atmosphere, or 0.04%. That is a very low concentration. Any claim of taking carbon dioxide out of the atmosphere should be met with that same question, “Where does the energy come from?”

Windmills get their energy from wind, solar cells from sunlight, and plants and algae from sunlight. Some of the schemes involving them may seem to counter Facts #1 and #2, but careful energy tracing will show that they do not.

Electricity and hydrogen, while clean in their immediate area, are only as clean as their sources. They are energy carriers rather than energy sources – they put a source of energy, say a nuclear reactor, into a form you can tuck into your car or home.

That’s all the thermodynamics you need to understand most of global warming.


Video from National Geographic.


52 replies
  1. 1

    […] at Balloon Juice, I’ve promised to write more about global warming. It’s the most important problem […]

  2. 2
    RepubAnon says:

    The Frat Boy laws of thermodynamics:

    1) You can’t win (Conservation of mass/energy)

    2) You can’t break even (Entropy increases in a closed system)

    3) You can’t get out of the game (the Universe is a closed system.)

    Anyone saying they can create energy by extracting hydrogen from water is getting more energy out than they put in… this violates the laws of thermodynamics.

  3. 3

    @RepubAnon: I knew someone would come up with this. But I wanted to apply thermodynamics more closely to the kinds of articles that appear on global warming. There are all too many GEE WHIZ articles on how carbon dioxide will be made into fuel or how hydrogen will solve all our problems. I want to give Juicers the tools to understand and criticize those articles. And yes, I know we’ve got a significant number of scientists here, but I’ve had some questions from scientists that could be clarified by applying Facts #1 and #2.

  4. 4

    Yes. Thanks for the list.

    Worth remembering that nuclear power is non-fossil energy. Not terribly happy about that solution, but we are desperate.

    @RepubAnon: That version is widely credited to CP Snow.

  5. 5

    Oh, related. Some science (SCIENCE!)

    Here’s an expert introduction to the scientific basis of our understanding of climate change, along with some approaches to solutions:

    Here is physicist Dr. Amory Lovins on alternative energy solutions:

  6. 6
    cmorenc says:

    …and plant photosynthetic processes, as well as marine limestone formation from accumulation of the exoskeletons of dead sea creatures, both as an end-product lock atmospheric carbon dioxide into solid forms, are ultimately driven by solar energy as the “extra” input source above thermodynamic loss in the processes themselves.

  7. 7
    p.a. says:

    Ask any scoffer where they’re hiding the money: if they’ve proved CO2 isn’t an atmospheric insulator, the must have the Nobel for chemistry, maybe physics also. Human population 1900 ~ 1.8 billion. 2018 ~ 7.5 b.

  8. 8
    Xboxershorts says:

    I’d like to offer up this shout out to Svante Arhenius, who did the heavy math involved in understanding energy transfer and storage in a closed atmospheric system with relevance of heat storing gasses back in 1890…without Svante we would never understand the ~400ppm threshold.

    At the same time, we’d known of the IR Energy storage capabilities of CO2 since the 1850s.

    Arhenius’ equation is real! The science is incredibly well established too!

  9. 9
    chris says:

    Thank you, Cheryl, concise and well done.

  10. 10

    @Raven Onthill: I haven’t paid much attention to Amory Lovins lately, but in the past he’s tended to oversell his solutions.

  11. 11
    Mike in NC says:

    Fat Bastard had a tremendous uncle who was a professor at MIT decades ago, ergo, that makes Fat Bastard an expert on all matters related to science.

  12. 12
    Chris T. says:

    @Raven Onthill: The nice thing about solar power is, it’s run via a giant nuclear plant about 93 million miles away where the atmosphere protects us from the particularly deadly parts of the radiation and all the radioactive byproducts are also 93 million miles away.

    (It’s a fusion reactor, rather than fission, but the point is, it’s tucked safely 93 million miles away.)

  13. 13
    NotMax says:

    Solar, hydro, wind, tidal generation. What do these have in common? The skip the step of boiling water to generate steam. Moving away from a steam-centric power structure is key. Switching to natural gas and bagasse is an intermediate step in that direction but by no means ought to be viewed as a solution.

    Elementary but bears mentioning.

  14. 14
    dmsilev says:

    @NotMax: There’s a form of solar power which doesn’t skip that step, solar thermal. The idea is to use a whole bunch of mirrors to concentrate sunlight on one point, where you heat up some working fluid (often water to steam, but sometimes other materials that serve the same purpose), which is then used to drive turbines and hence generators.

    It’s only viable in large-scale installations, and with the massive decreases in the price of photovoltaics is less competitive these days, but people are still building them for certain applications (for instance, if you choose the right working fluid, you get a lot of thermal mass that serves to spread out the power generated over a fair amount of nighttime, obviating the need to back up your solar cells with masses of batteries).

  15. 15
    🌎 🇺🇸 Goku (aka Amerikan Baka) 🗳 🌷 says:


    That sort of rationale flew maybe the first 10 or 12 times. No more.

    Well, I don’t know what to tell you. You need to understand the difference between fantasizing and laying out a worst-case scenario, which, by the way, I don’t think is likely to happen anyway (knock on wood) given the premise I was discussing in that thread: GOP vote rigging being so widespread and perfect to deny the Dems winning anything as the NYT headline hyperbolically wondered. I wasn’t being explicit either.

  16. 16
    JimV says:

    Great post. Thanks. I think we’ve reached the point where just about every post, comment, and conversation has to to bring up climate change and what we’re going to do about it. There are a lot of other problems, but if we don’t solve or adapt to climate change our civilization is over. I’m thinking of making (more of) a nuisance of myself on other blogs which I comment at to keep bringing it up at least once a day. I consider it strongly linked to over-population, over-consumption.

    Does he want a tax on children and a tax on consumption? Yeah, that and/or rationing. We had rationing during WWII and survived it. This problem is just as serious as WWII, probably more. (What did you do during the great war against global warning, grandpa?) (Nothing, honey, like most people. That’s why we lost.)

  17. 17
    Sneaux says:

    I am a big bag of ignorance, but what about dams built for hydro-electric also using the sequestered water for electrolysis to release hydrogen? Would that be carbon neutral hydrogen production for use in vehicles or other any other use?

  18. 18
    chris says:

    Andrew Gillum on climate change. Really want this guy to win.

    Getting crushed by @AndrewGillum – DeSantis looks like he just ate gas station sushi #FLGovDebate— laney (@misslaneym) 22 October 2018

    (Video attached)

  19. 19
    Amir Khalid says:

    Getting hold of the water is not the problem, as I understand it. The problem is finding an industrial process for stripping the oxygen from the water that uses less energy than you can get from the resulting hydrogen.

  20. 20
    Viva BrisVegas says:

    I would like to thank Donald Trump for making sure that Global Warming is not the number one problem facing humanity right now.

    He’s brought “Nuclear Armageddon” back to number one!


  21. 21
    Another Scott says:

    @Amir Khalid: As we are reminded above, we can’t break even. But more efficiency is always a worthy goal.

    There are teams of scientists working on new materials to efficiently “crack” water into hydrogen + oxygen just using sunlight. But to scale it up to an industrial scale to be useful, one has to separate the hydrogen and oxygen so that they don’t just recombine into water again. Once one adds in the cost and complexity of doing that, the “silver bullet” doesn’t seem to be so silvery. In other words, why not just buy a bunch of efficient solar cells, some efficient electrodes, and add some plumbing and tubes of water and do that souped-up version of what we did in high school science classes…

    They can already reach 30% system efficiency using PV to hydrogen.

    Research is great and very important, but sometimes having something that’s “good enough” is good enough to get started. Is 30% “good enough”? Dunno. But it’s better than nothing!


  22. 22
    Kent says:

    Also the scientific concensus around climate change is not remotely controversal or new. Here’s a clip from the Bell Telephone Science Hour in 1958. Your basic corporate-funded science broadcast to schools around the country 60 years ago

  23. 23
    trollhattan says:

    The “hockey stick” CO2/temp graph lines represent a game–hockey–played on ice!” How do you answer that hippies? QED and such.

  24. 24
    Mandalay says:

    @chris: From today’s editorial in the Miami Herald “Andrew Gillum will be a governor for all Floridians“, which endorsed Andrew Gillum over the vile Ron DeSantis:

    Gillum understands the urgency of addressing sea-level rise and other environmental challenges. And it’s heartening to see DeSantis oppose fracking and support building a reservoir south of Lake Okeechobee. This, and his decision to reject sugar-industry donations, helped win him the Everglades Trust’s endorsement. But he is less resolute about banning offshore drilling and his votes in Congress belie his status as a “green” candidate. He co-sponsored a bill that would block federal oversight of waterways and supported slashing both funding and projects that were under the Environmental Protection Agency’s authority.

  25. 25

    @Sneaux: To take my question from the top post, where do you get the energy for electrolysis? Are you thinking from the hydroelectric installation? Certainly possible, depending on the prices for electricity and hydrogen.

    @Amir Khalid: You have violated Fact #1! No such industrial process can exist. It depends on the overall economics.

  26. 26
    Viva BrisVegas says:


    Hockey is played on grass. Ice hockey is played on ice.

    /Pedant mode off

  27. 27
    Ruckus says:

    Don’t you have to have ice to play that on?

    Which means that it can’t be too warm or you have to use some energy to remove heat and make the water harder.
    But you knew that.

  28. 28
    Sneaux says:

    Yes, electricity from the dam, water from the reservoir combined to release hydrogen for storage of energy when not needed for the grid. Or serial dams to generate power to be used for hydrogen production to burn in lieu of hydrocarbons. I am from Missouri and we have nice lakes for recreation that also have hydroelectric generation like Lake of the Ozarks and the White River lakes in the south west.

  29. 29
    tobie says:

    I spent 12 hours driving this weekend. (Don’t ask why…families are so complicated.) I was listening to one show on a public radio station that mentioned that the spent nuclear rods buried 1/4 mile in the earth were emitting so much heat that evidently they were causing the rock beneath them to crumble and could end up releasing radiation that way. Cheryl, I don’t know if you’re still following this thread but have you heard anything about this? Dog knows what other geological effects the spent rods may be having.

  30. 30
    Ruckus says:

    Nothing is free. Most things cost money, most things cost energy. Like printing money. Electric cars sound great. Low emissions, except for mining and working with the elements needed for the batteries. To have enough batteries for everyone that needs a car to have one, is there enough of the elements that go into the batteries? What harm does that do to the environment? Hydrogen. Abundant, but attached other elements that require energy to separate. Could we make enough fuel cells even if we had the energy to separate it? What about the copper to wind the motors to use in the electric cars, no matter how we get the electrons moving. Petroleum. Has worked for 120 yrs as a fuel, which is about the only good thing to say about it. Except what do we do for trucks, ships, construction equipment? Trains. A lot of them are already electric, and without the internal combustion generator. How do you put supply wires and pendulums on airplanes?
    That’s just transportation.
    The world sure is going to look different in the next 50 yrs.

  31. 31
    🌎 🇺🇸 Goku (aka Amerikan Baka) 🗳 🌷 says:


    It’s sad that we knew in 1958 the basics of global warming and still did nothing. Just imagine if we had tried cap and trade then and the overall reduction of greenhouse gases. Granted, it would have been difficult convincing the Soviets to do anything considering their own poor environmental track record and distrust of the West, but it might be better today.

  32. 32
    joel hanes says:

    @Amir Khalid:

    an industrial process for stripping the oxygen from the water that uses less energy than you can get from the resulting hydrogen

    The Second Law of Thermodynamics assures me that no such process exists or can exist; in fact, it guarantees that we will never get back even as much energy as we put in. That doesn’t mean that it’s definitely not worth doing; we need transportation fuels. But hydrogen poses some handling and distribution problems.

    Ethanol from perennial-species biomass, like switchgrass, might be better.

  33. 33
    Ken Shabby says:

    @Chris T.:

    The nice thing about solar power is, it’s run via a giant nuclear plant about 93 million miles away where the atmosphere protects us from the particularly deadly parts of the radiation and all the radioactive byproducts are also 93 million miles away.

    (It’s a fusion reactor, rather than fission, but the point is, it’s tucked safely 93 million miles away.)

    Love this. It also ‘runs’ the wind, another source of energy, through windmills.

    I keep wondering if 50 years from now, people will ask why we burnt an irreplaceable lubricant and key component so many symnthetic materials derive from. It will seem criminally ludicrous.

  34. 34
    joel hanes says:


    Sounds like a frightened uninformed layman discussing sequestered reactor waste.
    Yah, “radiation could be released”, a quarter-mile underground. And it might get into any water trickling through the repository, and in the course of hundreds or thousands of years, make it into the biosphere — by which time it is likely much less radioactive.
    You want to ask those people “How much?”
    Dose rate is everything.
    The Rocky Mountains and the Sierra Nevada “release radiation”, all the time, as do virtually all granite formations.
    Every time you take a commercial flight, or go above 7000 feet altitude, you get mildly irradiated.

  35. 35
    joel hanes says:


    Our quandary would be much less fraught if, decades ago, we’d been wise enough to make inexpensive, confidential, effective contraception as widely available as possible.

    Because 2 or 4 billion people are much easier to provide for than 10 billion.

  36. 36
    Villago Delenda Est says:

    That’s all the thermodynamics you need to understand most of global warming.

    That’s more than your average Rethuglican can grok, though.

  37. 37
    Ruckus says:

    @joel hanes:
    I was irradiated every day for 9 weeks. On purpose. Of course it was a different type of radiation and it was for a rational purpose.

  38. 38
    Amir Khalid says:

    @joel hanes:
    Were that correct, the fossil-fuel industry would not be viable. In fact it uses less energy extracting and refining and shipping product than we get in usable form from that product, and yet the second law of thermodynamics remains intact.

  39. 39
    Ruckus says:

    @joel hanes:
    This is very true, fucking is obviously not good for the environment.
    We do it anyway. Often with smiles.
    But China is a valuable example, their one child per couple dictate seems to have failed, and rather badly. You encourage large families for centuries, to help with the food production and then all of a sudden realize that it’s not only no longer necessary, but counter productive (like how I snuck that in?) and try to change centuries of learned behavior………

  40. 40
    Pete Mack says:

    There is a bit more thermodynamics you need for this. Most significantly:
    1. The Maxwell-Boltzmann equation, which determines temperature as a function of energy output as blackbody radiation–and vice versa. (Technically statistical mechanics, rather than classical thermo.)

  41. 41
    joel hanes says:

    @Amir Khalid:

    You really should stop commenting about science.

    I’ll try to make it obvious.
    Hydrocarbons such as oil are unburnt fuel. Their hydrogen and carbon bonds contain stored energy captured from sunlight in an earlier age of the world. Those hydrogen and carbon atoms would love to assume a lower-energy state by combining with oxygen instead of with each other, to make CO2 and water, and releasing the stored energy in the process.

    Water is the ash of already-burned hydrogen. It has no available stored chemical energy in its bonds; it’s a low-energy state. To get free hydrogen that can be re-burned, you must put enough energy into the water molecules to break the hydrogen-oxygen bond and separate the atoms. When you re-burn that hydrogen, by re-combining it with oxygen, the maximum energy produced is guaranteed by the second law of thermodynamics to be somewhat less than the energy you put into separating the hydrogen and oxygen in the first place.

  42. 42
    Amir Khalid says:

    @joel hanes:
    Okay, got it.

  43. 43
    Robert Sneddon says:

    @Ken Shabby: The Sun is also responsible for millions of cases of melanoma each year since there’s no shielding or structural protection from its dangerous emissions. There’s also heatstroke which injures and kills people around the world.

  44. 44
    low-tech cyclist says:

    @Raven Onthill:

    Worth remembering that nuclear power is non-fossil energy. Not terribly happy about that solution, but we are desperate.

    Neither am I, especially because we’ve never really solved the problem of what to do with the nuclear waste.

    But messing up a handful of sites with nuclear waste that has a half-life measured in millennia, as bad as that would be, would be far less damaging to our environment than cooking the whole damn planet. So if nuclear power can be part of the solution, then so be it.

    (Lord, I hate to say that. But there’s no way around it anymore.)

  45. 45
    Fair Economist says:

    Nuclear is already looking like not part of the solution because plants have a 30-50 year life and it looks like we can be all renewable before that. The economics are bad.

  46. 46
    Robert Sneddon says:

    @Fair Economist: Economics say CO2-emitting fossil gas is a good replacement for fossil coal for electricity generation and the effects of climate change don’t cause problems with the next quarter’s financial results. Economics drive a fervent desire for cheap energy at all costs and that means atmospheric CO2 levels will continue to rise for at least the next thirty years and probably after that too. We (the global We) really need to stand Economics up against a wall and shoot it, along with all the fossil fuel executives and their workforces.

    Renewables are the energy source of the future, and always will be. France effectively decarbonised their electricity generation in a period of fifteen years or so starting in the 1970s by turning out nuclear reactors like jelly babies. Germany has spent more money over a similar period on renewables and still emits similar amounts of CO2 per capita than it did when it started while they plan to import even more Russian gas to keep their lights on (the Nord Stream 2 pipeline expansion). The Green Germans also have the effrontery to charge their population twice the price per kWh of nuclear France next door while actually generating most of their electricity from cheap lignite and Russian gas.

  47. 47
    Fair Economist says:

    Nuclear can replace coal, but coal plant construction is dropping off a cliff for the same basic reason – you can’t justify baseline power plants with a long life anymore. Nuclear can’t replace gas because gas is peaking power and nuclear is slow to change power production.

    The only plausible use for nuclear I can think of is ocean transport.

  48. 48
    Robert Sneddon says:

    @Fair Economist: Nuclear runs balls-out almost all of the time anyway. The fuel cost is trivial so there’s no financial benefit to dialling the power output back. I don’t think there’s a nation or grid that has so much nuclear capacity that would require that capability. In reality modern nuclear plants can be swung down and back up again in an hour or so due to better design and experience in operations. It almost never happens for the reasons I mentioned. Reactor downtimes are usually scheduled for periods of the year when demand is lower — the UK is currently carrying out mandatory inspections on a number of its reactors but they will be back in operation for the high-demand period through the winter.

    As for gas being “peaking”, in the UK where I live gas is effectively a baseload generator now since we ditched almost all of our coal plants. We have about 35GW of gas capacity, all modern combined-cycle gas turbine (CCGT) plant and it’s a rare day we don’t have at least 15GW of it turning and burning. Last winter I saw one day when we had 25GW of gas-generated electricity being added to the grid as the wind had died down at night so the renewable input was negligible. Our 7GW of nuclear installation was running full-tilt at the time too, of course. (Quick check, an internet reporting page says right now we’re producing 14GW of gas, 5.5GW of nuclear and 6.5GW of wind along with power from biomass imported from the US, a spot of solar and hydro and a few GW from the French nuclear and Dutch gas generators to meet a total demand of about 37GW).

  49. 49
    billcinsd says:

    @cmorenc: Also, some chemical reactions can occur spontaneously without any heat input at all. Heck, some give off heat while this happens.

  50. 50

    @tobie: I would need some specifics to check up on this. I haven’t heard any such thing. NPR sometimes gets nuclear stuff wrong.

  51. 51

    @Pete Mack: Not for the average citizen.

  52. 52
    G.R.L. Cowan says:

    @tobie: No spent fuel rods have been buried, anywhere, that I know of. They are all in water pools or — if old and cool enough — dry casks. Some dry casks are in a photo I used at

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