Greenhouse Molecules Laid Bare

The Earth is a bit like the human body; its temperature is very finely balanced, and when it gets slightly out of whack, big things can happen. In the case of our home planet, gases in the atmosphere play a vital role in maintaining this delicate equilibrium, by balancing the absorption and emission of all the electromagnetic radiation (microwaves, infrared waves, ultraviolet light and visible light, for example) reaching the surface of the Earth.

As reported recently, the Earth is getting warmer. Scientists believe the main driver behind this warming trend is rising levels of man-made greenhouse gases. These gases, which we pump out into the air, act to trap heat radiation near the surface of the Earth that would otherwise be sent back out into space. Carbon dioxide (CO2) is the Paris Hilton of greenhouse gases, and gets a lot of face time because its concentration in the atmosphere has increased relatively rapidly since the Industrial Revolution. But methane, nitrous oxide, hydrofluorocarbons (HFCs), chlorofluorocarbons (CFCs) and perfluorocarbons (PFCs) are also important agents of global warming. Some of them are actually much more potent than CO2 and they stick around for hundreds to thousands of years longer. This has some scientists concerned that these B-listers could actually impact global temperatures significantly more than CO2.

greenhouse warming cartoon

In a new paper, Partha Bera and colleagues at NASA’s Ames Research Center and Purdue University put these gases under the microscope to find out exactly why they are such powerful heat trappers. They focus on CFCs, HFCs and PFCs — all chemicals containing fluorine or chlorine — that are used in medicine, fridges, and as solvents, among other things. By probing the molecular structure of these compounds, they have found that molecules containing several fluorine atoms are especially strong greenhouse gases, for two reasons. First, unlike many other atmospheric molecules, they can absorb radiation that makes it through our atmosphere from space. Second, they absorb the radiation (and trap the heat) very efficiently, because of the nature of the fluorine bonds inside them. (In technical terms, fluorine atoms create a larger separation of electric charge within the molecule, and this helps the molecular bonds absorb electromagnetic radiation more effectively.) HFCs and other fluorine-based gases have been called “the worst greenhouse gases you’ve never heard of.” Now we know why.

Until now, scientists had not looked in detail at the underlying physical or chemical causes that make some molecules better global warmers than others. Bera and colleagues say that their work should help improve our “understanding [of] the physical characteristics of greenhouse gases, and specifically what makes an efficient greenhouse gas on a molecular level.” They hope their findings will be used by industry to develop more environmentally-friendly materials.

Amber Jenkins, NASA’s Global Climate Change team 

6 thoughts on “Greenhouse Molecules Laid Bare”

  1. I think the first step is to prevent the release of these compounds. The second step is to find a way to reverse what has already been done, “cleaning” the air. But how. I believe that the most efficient strategy is the strategy of the pool. When the pool is dirty is used flocculation and sedimentation. With the chemicals harmful to the atmosphere makes up combinations with other molecules to see is one that makes flakes and / or settle. It has to do many combinations to find (pray the good God) a combination. I do not know which elements are used in the cleanup of a pool, I do not own one, but it is a good start. The issue is finding a compound that combines or reacts with these others and make them settle. You can use a glass case sealed and study what happens with different mixtures: air, (with or without steam) CO2, CFCs, HFCs, PFCs, etc.. I believe that soon you will find a solution. I’m hoping.

  2. I agree with Victor that the first step would be to prevent release of the offending compounds. But I think this is a difficult thing to do. As I type this, I am using electricity to power manufactured goods. The computer I type on took quite a bit of energy to produce, and I use power to use it. I am surrounded by manufactured things. I worked for a small manufacturing plant a while back. We made well screens used in oil and water production. The electric bill there was about the same as the total of all the employees’ electric bills. Takes lots of welders and heat treating ovens to manufacture those screens and those use lots of power. And pumps, lifts and lights…The list of things made and bought and used is longer than I can type. And all the people breathing air not making use of nitrogen but consuming oxygen then releasing carbon dioxide. People like air conditioning and fire extinguishers. People like to keep their houses warm in winter and cool in summer. We can make things more efficient, and we have. To change things to the way things were before 1950 might be difficult, and even if we did, some might want to look at how hazardous waste was disposed of then. We could take it back a bit farther. How long has the Northwest end of the Adriatic Sea been flooded with human waste? Humans have been messing up the environment for quite a while. Use solar collectors, you make shade on the ground. Use wind, you slow down the breeze and some say disrupt birds. Nuclear power? Where does the waste go? And any power supply used still has to be manufactured. Communicate on the internet or by smoke signals? Both make smoke. Not as much manufactured equipment needed to make smoke signals though.

    Cleaning the atmosphere is an interesting proposition. I don’t currently own or take care of a swimming pool, but years ago I did. Clarification was done with filters. Water was moved by pumps. Killing bacteria was accomplished by using calcium hypochlorite. Ph was maintained by using hydrochloric acid. The filters were made more effective with alum, hydrated aluminum potassium sulfate. People like to swim in a safe environment. Clear water free of bacteria and don’t like their eyes to hurt. So the levels were monitored hourly by a lifegaurd(me)who also had to watch for actual emrgencies. No one drowned in the clean pool I ran. No one got sick either. But lots of manufactured goods and chemicals were used. Keeping the swimming pool clean and safe was a big important job for me. It is hard for me to imagine cleaning the atmosphere on a large scale. Spray some stuff to make bad molecules precipate to the ground seems impossible. Planet Earth is mostly covered with water. Is making the new compounds fall on dirt better than making them fall in the ocean? How will the miracle molecules be applied to the atmosphere? Crop dusters can’t fly to a hundred thousand feet, and even if they did and that were high enough, how many fuel burning crop dusters would it take? And how many miracle molecules would have to be manufactured?

    Ride a bamboo bicycle to work. Don’t eat things that make you fart. Maybe the best thing to reduce global warming would be to induce global cooling by using heat from within the Earth to power the things we like to use. But be wary. That might bring on an ice age, make Earth an icy comet. If humans are to survive in the long run, eventually we’ll need to get off this planet. That means human space flight. I see only two other possibilities. Reduce consumption or reduce population. Neither is probable, the trends support the opposite.

    Now I’m going to watch some NASA TV…Wally

  3. Pretty cool post. I just stumbled upon your blog and wanted to say that I have really liked reading your blog posts.Thanks a lot for sharing.keep up the good works.

  4. I'm really fascinated by this article. I think the author has done a great job. Thumbs up

  5. These gases, which we pump out into the air, act to trap heat radiation near the surface of the Earth that would otherwise be sent back out into space. Carbon dioxide (CO2) is the Paris Hilton of greenhouse gases, and gets a lot of face time because its concentration in the atmosphere has increased relatively rapidly since the Industrial Revolution.NASA TV…goood

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