Organic Gardeners Rejoice! Methane From Compost is OK

By June 24, 2012 November 14th, 2012 What we can do

Methane: so much news.  First, methane from the decomposition of recently grown organic stuff is not really a problem. How ’bout that. It’s fossil methane that’s a problem.  Recently grown organic material cycles through the growth/decay process rapidly relative to climate change’s semi-geologic timescale. So it’s factored in to the equation. Burning fossil fuels releases fossil methane that has been stored for hundreds of millions of years and is considered a 100 percent addition (anthropogenic) to the atmospheric load. But methane from recently dead plant decomposition is not a problem. It’s only the fossil methane that adds to the global greenhouse gas imbalance.

That said, if all the plants die at the same time like when we have a forest die-off, their organic material decomposes all at the same time creating a problem.  Last year the forest die-off in Austin was not too bad, but last year was just a preview. The Texas Forest Service says 500 million trees died. If each tree has 1,000 pounds of carbon, this is 0.250 gigatons of carbon alone. Globally we emit less than 10 gigatons of carbon a year, so this is a lot of carbon. Its impact on the atmosphere is not as extreme as it would appear however because it takes generations or longer for all of the dead wood to decay. More decays sooner rather than later, so it is still a big problem.

Permafrost melt is another good thing talk about while on this subject. Most permafrost has not melted in the last 3 million years. Most permafrost is half organic material or more, deep frozen in a partially decomposed state. It’s a mixture of naturally frozen partially decomposed compost and ice, saved in the freezer for millions of years.  If you have never seen permafrost, it forms beneath the “active” layer of soil/living material. In the tundra, this active layer has very little soil, but a foot or two (!) of mosses and lichen. The bottom of the active layer is dead and slowly decomposes as it thaws out every summer for a few weeks. As the tundra above slowly grows, the bottom layers slowly thaws out less and less until they are 100 percent entombed in ice. This is permafrost.

Permafrost can be thousands of feet thick. Because it is rapidly melting now due to global heating, it’s causing problems as the partially decomposed organic material is defrosted. This is basically fossil organic material and it is all decomposing and releasing its methane (and carbon dioxide) all at once whereas if the same amount of organic that thaws each year would have taken centuries or millennia to die and decompose naturally. There is as much methane in permafrost as there is in all fossil fuels, already burned and still in the ground.

Frozen methane on the ocean floor is even more fantastic. As organic material dies in the ocean (mostly plankton, algae, diatoms and other microscopic sized or very small plants and animals), it sinks to the ocean floor and decomposes. The methane released in the decomposition process then rapidly freezes because of the great pressure and cold temperature there. It has been doing this for hundreds of thousands and millions of years—maybe even 55 million years. (Back to the Paleocene-Eocene thermal Maxim. this was a hyper-warming period in Earth’s history where it was likely that a great deal of frozen methane on the ocean floor thawed and created an  extinction event.)

All of this partially decomposed fossil organic material counts because its not in the organic decomposition cycle. It has been left out of the loop in the deep freeze for fossil lengths of time. When it thaws it adds to the load in the sky that makes it warmer.

Methane is peculiar substance. On the surface, methane freezes at minus (-) 296 F. Beneath about 1,000 feet of water, at greater than 500 psi, the freezing point rises to near + 40 degrees F as methane forms an ice composite with water called methane clathrate. Because water temperatures across the globe at this depth are almost always in the low thirties, the methane freezes.  There is enough frozen methane on the ocean floor to equal two or three times all the fossil fuels in existence and already burned. 

In the Laptev Sea right now, north of Siberia, the Arctic Ocean has warmed enough to vent thawing clathrates (methane.) These clathrates were formed as permafrost during the last ice age when our oceans were about 300 feet lower than today. They have been submerged for 10,000 to 18,000 years. that amounts to more than all of the rest of the current methane venting from all of the rest of the worlds oceans combined.

Methane is a very dangerous greenhouse gas. And even though it has a life in the atmosphere that is twenty or thirty times less than CO2, it can cause a lot of trouble. Twentieth century wisdom about methane’s global warming potential was that it was 25 times more potent than carbon dioxide based on a standard global warming potential scale of 100 years. Today, more knowledge has allowed us to understand that it’s more like 33 times more potent. But this is based on a 100-year time frame.

The most important time frame in our global warming future is the short-term climate time frame. This is the next 20 to 40 years, not the standard 100-year time frame normally used for global warming potential measurements. The reason is because of irreversible abrupt climate changes. We have seen these things happen 23 times in the last 100,000 years where Earth’s average global temperature changed 10 degrees F in a decade or two, or even crazier; when dynamics were “pushing” the atmosphere at its greatest, we saw 10 degrees of change across the planet in just a few years. And remember, 10 degrees is average across the globe. Over land it’s more like 20 degrees. This is because warming is much less over the oceans and the oceans cover 70 percent of Earth’s surface. So the reason that the short climate time-frame is so important is that we are quite possibly dangerously close to climate tipping points. Certainly we are far closer than we were twenty years ago when we were supposed to have started reducing emissions. And the faster climate has changed naturally in the past, the stronger these climate tipping points appear to have been.

Today we are pushing our atmosphere 14,000 times faster than at any time for certain in the last 610,000 years and possibly as fast as when the giant asteroid struck the Yucatan Peninsula and the dinosaurs went extinct 65 million years ago. We are highly poised for an abrupt climate change. There’s another reason why the short term climate time frame is important. Methane reacts with different things in our atmosphere and creates byproducts.  Hydroxyls are a good example of things that react with methane. Hydroxyls are considered our atmosphere’s cleaning machines. They react with pollutants and create inert materials that rain or fall out of the sky. When hydroxyls react with methane, other global warming gases are formed like more CO2, or nitrous oxide or any number of other things. These global warming gases have indirect effects that also warm the atmosphere. Also, when the short term time-frame is considered. Methane has much more of a warming potential in the short term than in the 100-year time frame because after a dozen years, half or more of methane has itself decomposed and warms no more. So the 100-year average reflects this and lowers methane’s global warming potential relative to the short-term. So the final word about methane, when all of the complicated math is done, it is 183 times more potent at warming than carbon dioxide in the short-term climate time frame (20 to 40 years).

It is very important that we understand what we need to do and what we don’t need to do. Because a lot of simple things like methane from compost do not impact climate change, where we understood before that they were important, we need to take that energy that we would have willingly put into saving the planet from methane from decomposition of organic material in compost and apply it to our will to elect leaders who are willing to do something about the problem, OR, to influence Conservative leaders who think climate change is rabbit poo. Teddy Roosevelt, a Republican, was likely the greatest environmental conservationist that ever was. Even Nixon, another Republican, was a great conservationist. He created the Clean Water Act, the Clean Air Act, the Pesticide Reform Act, the Endangered Species Act and the EPA. 

It can be done by Conservatives. The environment is only recently the exclusive domain of Liberals. It can be done and it will be no more expensive than installing toilets across the planet for the last 100 years; or than the amount that us American’s spend on our military every year not counting wars, or that we spend on advertising across the planet every year. It will be four to five times less expensive than us American’s alone spend on health care every year.

And keep on compostin’.