A Basic Primer on Greenhouse Gasses and Comparisons

I would say that we are a community based on objective analysis. In the case of greenhouse gasses we are talking about looking at the science. It's not scary really, and I promise to not whip out any formulas or my slide rule.

The Earth is a free body in space, which means that it is not physically attached to any thing else. It seeks equilibrium in all things, motion and thermodynamics. In order for the Earth to have a constant average temperature, thermal energy gain from the sun must be balanced by thermal energy radiation into space. Unless we can find a giant source or sink of thermal energy on the planet then this is the only mechanism.

First important factor: In order for the Earth to have a constant average temperature, thermal energy gain from the sun must be balanced by thermal energy radiation into space.

Thermal energy is radiated as long wavelength light, infra-red from the surface of the planet. Believe it or not, this must be the at same rate of energy overall as we get from the sun. This might not seem right intuitively, since we know how hot sunlight is, about a kilowatt per square meter and we can't see the radiation from the planet into space, but trust me (but verify) this is correct. If we did not have an atmosphere this transfer of thermal energy onto the planet and off of the planet would be represented by very simple equations and the Earth would be considered a "black body".

On the real planet this transfer in and out of thermal energy has to pass through the atmosphere. There are considerable factors to consider to model this, clouds, reflectivity of the surface, etc. but for this essay I'm going to limit it to thermal energy radiated back into space as that's where the primary problem lies.

Second important factor: The rate of average energy radiation into space is dependent of the average temperature of the surface of the planet. A hotter planet radiates more thermal energy.

Now let's look at what happens as the infra red radiation tries to go to Apha Centauri. It runs into the atmosphere. Poor Mr. Photon! The atmosphere is composed of many gaseous molecules. Some of these molecules are very efficient at absorbing this radiated energy. The molecules heat up as they get bombarded by Mother Earth's radiant personality. Now here's the fun part. They then will re-radiate this energy in all directions. Half of it continues to outer space the other half is radiated back to planet Earth. Now you know how GHGs work and now you are dangerous (I hope).

To get a sense of how the various molecular components of the atmosphere contribute to this effect you need to know lots of things. 1- How effective is a particular gas in absorbing infrared radiation? 2- How many gigatons of this particular gas are in the atmosphere, and 3- what is the natural disposition of that particular gas.

The greatest GHG effect is from water vapor. It's very good at absorbing and there is a lot of it. Water vapor is in a constant state of equillibrium as part of the water cycle on the planet. It's been stable for a long time and keeps our planet hospitable. Now we turn to the class of Climate Crisis molecules, the ones that are increasing due to mankind's activities.

The standard by which we assign potency to GHGS is CO2. It's a moderate absorber, but there is a lot of in the atmosphere as measured in Gigatons. It is very long lived as there is no process that breaks it down while it is a gas in the atmosphere. It's hard to get estimated, but they range from 100s to 1000s of years. There are other CO2 exchange mechanisms on the planet that complicate this. It's generally acknowledged that CO2 is going to be the civilzation killer eventually if we don't control it.

Nitrous oxide is a very potent GHG, about 289 times a potent as CO2. Fortunately there is relatively a small amount in the atmosphere, but we are adding to it.

Methane, CH4, is also a potent absorber. Here's where the fun technical stuff comes in. Methane is broken down in the atmosphere and eventually becomes CO2. The rate of this chemical process is expressed in half-lives. That is the time for one-half of the molecules to be removed. For CH4 this number is 7 years. That means that in 7 years the CH4 concentration from a single release will be one-half. In 14 years it will be one-quarter. In 21 years it will be one-eighth. This complicates expressing its potency relative to CO2, so usually a time period is specified, but it is much better to understand this mechanism. CH4 is about 100 times as potent as CO2 when initially released. That's what you need to know. Each release then decreases in potency over time. Its overall effect is 72 times a potent as an equivalent release of CO2 over a 20 year period and 25 times as potent in overall forcing of warming over a 100 year period. Don't confuse this with its instantaneous effect of 100X initially and about .02X of the warming effect of CO2 in 100 years (12.5 half-lives). Some scientists (I love that phrase..it really means that I don't have the time to re-find them on the web right now) feel that CH4 is not the problem in the long run, that it should be looked at as more of an accellerant for burning earth, but it's the CO2 that will keep the fire going.

Where are we headed? It's not good as you all know. From the First and Second important factors we know that the Earth's average temperature must go up as greenhouse gases impede the flow of thermal energy into space. Right now we are out of balance. There is more energy, in kWH striking the surface of the planet then is being radiated into space. That means that if we suddenly and miraculously stop all GHG emissions tomorrow the planet will continue to heat up until it reaches thermal equilibrium. But, and this is the real problem, we continue to emit more GHGs. As an engineer I look at the graphs, for instance CO2 ppm, and I have a hard time believing that we are going to slow down the rate of emissions of CO2, that is flatten the slope of the line until it is horizontal in anything less than multiple human lifetimes. But the reality is that we have only a few decades to do this.

Hopefully you have followed all of this. I'll check tomorrow and try to answer any questions. Please feel free to add or correct any of this essay, I trust you folks.

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Bluesee's picture

I wonder what prescription there is to flatten that curve today. There is ultimately a schism in the offing, as the effects continue.

Al Gore, the Druid
Jimmy Carter the Energy Nut

These prophets could have saved us, if we had listened to them instead of mocked them, If we just didn't elect Nixon, Reagan, and both Bushes, perhaps.

Your encapsulation of the Science was awesome, it reminded me of college, haha, re-radiation! Fun stuff. sigma T to tha fourth power! and beyond!

I remember in college is was associate to prof and I had them analyze why "Plants in Space" is a very hard problem, for kinda the same reason. I taught them "back of the envelope" engineering. Good times!

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Bernie is a win-win.

WoodsDweller's picture

The IPCC calls this "Global Warming Potential". From wikipedia:

https://en.wikipedia.org/wiki/Global_warming_potential
referencing 2013 IPCC AR5 p714

CH4 lifetime (half-life) 12.4 years, GWP (20 years) 86 (100 years) 34
For some reason the press keeps mis-reporting 34 as 25.

OTOH, this article, also referencing 2013 IPCC AR5
https://en.wikipedia.org/wiki/Atmospheric_methane
reports it as 29 and "and 32 times the effect when accounted for aerosol interactions"

The half-life is accurate in normal circumstances, but is governed by the availability of hydroxyl radicals in the upper atmosphere. In the Arctic, in particular, those radicals can become depleted in winter when there is no sun creating them. One could also envision a large methane event overwhelming hydroxyl production, which is a function of water vapor concentrations and incident UV, it does not conveniently scale to our needs.

The thing is, methane concentrations in the atmosphere are increasing - they've more than doubled since pre-industrial times - so using the decaying value of a particular sample seems wrong. If you want to assess the impact of 1800 ppb CH4 you should use the base value, which I think is 120, not the declining value (unless levels actually begin to decline). That gives you a CH4 equivalent of 220 ppm CO2 (overall CO2 equivalent of 630 ppm or so), rather than the 60 or so equivalent you get with the declining value (480 ppm equivalent frequently reported).

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"The greatest shortcoming of the human race is our inability to understand the exponential function." -- Albert Bartlett
"A species that is hurtling toward extinction has no business promoting slow incremental change." -- Caitlin Johnstone

I found in researching GHGs that each article seems to have their own set of numbers on half-life of CH4 and warming equivalency. There is a good article in MIT news http://news.mit.edu/2014/how-count-methane-emissions-0425 about CH4 equivalency and it references work just published in the journal Nature Climate Change.

As reported in a paper published today in the journal Nature Climate Change, authored by MIT assistant professor of engineering systems Jessika Trancik and doctoral student Morgan Edwards, this conversion factor (called the global warming potential, or GWP) may significantly misvalue methane. Getting this conversion factor right is challenging because methane’s initial impact is much greater than that of CO2 — by about 100 times. But methane only stays in the atmosphere for a matter of decades, while CO2 sticks around for centuries. The result: After six or seven decades, the impact of the two gases is about equal, and from then on methane’s relative role continues to decline.

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Capitalism has always been the rule of the people by the oligarchs. You only have two choices, eliminate them or restrict their power.

The release of methane sequestered in the permafrost regions of the northern hemisphere can be reduced by methane eating bacteria if the temperature of the substrate is between 2C and 5C. Below 2C, the bacteria are inactive and above 5C the amount of methane released overwhelms the bacteria available to metabolize it. There is a terrific amount of methane in the permafrost regions and its sudden release can raise the earth's temperature so quickly that the ice caps melt, changing the currents in the oceans.

There is even more methane sequestered in the oceans which is in danger of being released.

In the contiguous 48 states, one-third of all methane released into the atmosphere come from domestic cattle.

I will be glad to be corrected but this is what I have read.

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"The justness of individual land right is not justifiable to those to whom the land by right of first claim collectively belonged"

Lookout's picture

Also called albedo is one way energy is reflected back into space.
http://www.eoearth.org/view/article/149954/
Recent models show the effect of cloud albedo was overestimated. As ice melts albedo is also reduced. We're cooked!

As far as methane release, cows are a source, but leaks at fracked wells like the one in California are thought to be a major source also. The scariest (to me) is the methane release from the arctic because it has a positive feedback loop...release->warming->more release....

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“Until justice rolls down like water and righteousness like a mighty stream.”

NCTim's picture

Climate Change: US Landfill Methane Emissions Grossly Underestimated, Finds New Study

Landfills are the United States’ third-largest source of methane -- a potent greenhouse gas nearly 30 times more effective than carbon dioxide in trapping heat and spurring global warming. However, as a new study shows, this number might be much higher, as Americans are dumping more than twice as much trash in landfills as the U.S. Environmental Protection Agency (EPA) has estimated.

The Yale University study, which calculated the waste volume in more than 1,200 municipal landfills, revealed that in 2012, 262 million tons of solid waste was disposed of in the country -- a 115 percent increase over the EPA’s estimate of 122 million tons for the same year.

===================================
http://www.ghgonline.org/methanelandfill.htm

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The individual has always had to struggle to keep from being overwhelmed by the tribe. If you try it, you will be lonely often, and sometimes frightened. But no price is too high to pay for the privilege of owning yourself. - Friedrich Nietzsche -

utilization that have to be considered "low hanging fruit".

Land fills, waste water treatment facilities and large animal confines. The "waste" responsible for methane emissions in these arenas is concentrated and therefore easier to convert to usable energy (as opposed to following a herd of cattle across range land and scooping up cow pies).

Some mitigation has already happened in all 3, but are "tip of the iceberg" or "for show" projects. Or worse, projects paid for by the antagonists and designed to fail.

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21st Century America: The distracted, superficail perception of a virtual reality.

I think you bring up two excellent points: The methane released because of oil and gas extraction; and the fact that methane released in the arctic regions will create a positive feedback loop.

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"The justness of individual land right is not justifiable to those to whom the land by right of first claim collectively belonged"

Harper's Index, May 2016

Percentage of US science teachers who "emphasize" that global warming is likely due to natural causes : 30

How is we gonna save our chillren if we ain't teachin' 'em proper?

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21st Century America: The distracted, superficail perception of a virtual reality.

Lookout's picture

I started teaching about global warming in the 80's. This is about the time Exxon started denying it.
http://insideclimatenews.org/news/15092015/Exxons-own-research-confirmed...

Then toward the end of the 1980s, Exxon curtailed its carbon dioxide research. In the decades that followed, Exxon worked instead at the forefront of climate denial. It put its muscle behind efforts to manufacture doubt about the reality of global warming its own scientists had once confirmed. It lobbied to block federal and international action to control greenhouse gas emissions. It helped to erect a vast edifice of misinformation that stands to this day.

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“Until justice rolls down like water and righteousness like a mighty stream.”

Hawkfish's picture

For those who want to dig into the research a bit more, you can find about 10 years of articles on this topic written by the researchers themselves over at RealClimate.org. They also talk about the communication issues around science and public policy.

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We can’t save the world by playing by the rules, because the rules have to be changed.
- Greta Thunberg

How do you, any of you, deal with the despair that knowing this information brings? I had, at one point, held the hope that decreasing methane would buy us some time in converting over to renewable energy. Since the large methane leak in California and methane leaking from the permafrost, I've no bright spot to look to. My husband is a climate activist. My son teaches environmental justice at the university level. My daughter was one of Naomi Klein's researchers for This Changes Everything. I have felt that we could make no progress with Citizens United in place. Spreading fracking globally has helped Chevron, one of the companies that gave generously to the Clinton Foundation. I don't know what I'm supposed to do at this point and sometimes I can't get beyond despair.

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Haikukitty's picture

My only relief is that we chose not to have kids. It ends with us so although I'm still in despair, I am relieved of that worse despair of worrying for my children and grandchildren.

I don't know how to deal with it. I find myself avoiding the information, because I know its bad and I don't know how to think about it without panicking. I don't know how to prepare for it.

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I have no idea how to prepare for a potential(likely?) global catastrophe when powerful storms and deadly heatwaves will strike almost at random.

I think the best thing to do is to fight for a political/economic system that promotes sustainability and has the courage to say "Enough" to mindless consumerism. It's also important to make the effort to live in a manner so that whatever portion of the earth you exercise some control over, plenty will be left for the next generation.

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"The justness of individual land right is not justifiable to those to whom the land by right of first claim collectively belonged"

featheredsprite's picture

Climate change is here. I believe we have passed the tipping point and there's nothing we can do to stop it now. We just have to deal with the consequences.

I'm suggesting that you redirect your very logical despair towards helping victims of climate change, humans and other animals. It might not change reality much but it could help you to feel better.

We tried. We failed. [[hug]]

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Life is strong. I'm weak, but Life is strong.

You can't give up. You have to go forward and act morally. You have to know that you cared and did what you could do to save civilization.
You can support candidates with a donation who understand the nature of this crisis. You can demonstrate. Noam Chomski believes that we can only get change by public demonstration. At some point we will be able to turn out millions of people in DC and in the big cities to demonstrate against the fossil fuel industry and a political establishment that doesn't seem to give a damn.
I'm hoping that Bernie and Jill get together. If there were a permanent large third party that could at least swing elections, we might get somewhere.
No politician is scared shitless of the sustainability movement. We need to change that.
Bernie's Run has changed everything. We need to funnel that energy and cash flow into fighting the establishment and promoting Climate Crisis to front-stage.

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Capitalism has always been the rule of the people by the oligarchs. You only have two choices, eliminate them or restrict their power.

I agree. I had thought that when there was a march planned here in Baltimore to show support for Bernie, that the climate groups should have been contacted and asked to organize for that. It is a natural alliance, and climate groups have been forming for years.

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Pluto's Republic's picture

Thanks for taking the time to write it. The tone of the information is, itself, an arena for satisfying learning.

I do have a question: Which planets in this solar system do not have energy transfer equilibrium, or is that a balance that occurs on planets when and if they have the potential to host life?

Your image of atmospheric particles/gases reflecting the heat trying to escape the planet, back onto the planet, is clear and enlightening. It's happened before (as a result of a planetary catastrophe that polluted the atmosphere) — which ironically created the fossil fuels that are at the heart of the today's dynamic environmental fail. In this case, the catastrophe is too-early technology development, exacerbated by grotesque overpopulation of the under-evolved dominate species.

Such a circular extinction event kinda makes you think that the entire purpose of life may be to create fossil fuel dumps — gas stations for intersteller travelers from a more evolved universe. That was the conclusion Kirk Vonnegut reached, in one of his better books. Maybe he was onto something….

Again, thanks for a fine essay that leaves room for for the audience to explore.

Yr friend,

Pluto

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____________________

The political system is what it is because the People are who they are. — Plato