An Inconvenient Truth About Composting Revisited

(here is the link to all my posts)
Although composting has a very strong “green” reputation, it isn’t without it’s environmental issues.  Compost is an important source of fertilizer for Organic crops, and is widely promoted as a “green” alternative to synthetic nitrogen.  The inconvenient truth is that, as a nitrogen fertilizer, compost has a carbon footprint more than 10 times as large as that for the synthetic nitrogen used in conventional farming.  It will never happen, but if a significant percentage of crops were ever to be fertilized with compost, it would be a very bad thing in terms of climate change.

In July of 2009 I posted an obscure document about this topic titled, “The Carbon Footprint of Organic Fertilizers” on Scribd.  It just passed 5000 reads, and that inspired me to write another post about the conversations I’ve been having on this topic for the last two years.

Why Such A Big Footprint?

The reason that compost-based nitrogen has such a big carbon footprint is because, during the composting process, micro-sites in the pile run out of oxygen because there is so much being consumed by the microbes.  Under those circumstances, other organisms make methane or nitrous oxide (21 and 295 times as potent as CO2 as a greenhouse gas).  Two to three percent of the carbon is emitted as methane even in a very well run, commercial-scale composting operation.  Because it takes many tons of compost to provide the fertilizer for an acre of a crop – the greenhouse gas contribution per acre is very large.  The conclusion from this is not that composting is a bad thing, but rather that it is definitely not an acceptable fertilizer alternative for the bulk of agriculture.

The Discussion

Since January of 2009 I’ve discussed this topic with dozens of qualified  academic scientists, with scientists that work for the Rodale Institute and the Soil Association in the UK, and with representatives of several Environmental Groups.  The basic conclusion has held up – “there really is a large carbon footprint associated with fertilizers that come from composting.”

Still, many interesting issues have been raised and need to be considered:

Who’s Footprint Is This?

Manure is a major waste product of animal agriculture.  It has many environmental downsides, but it also provides the fertilizer for about 5% of US crops. Greenhouse gas emissions that come from “manure management” are certainly related to animal product production, but there are areas that pass the boundary. If manure needs to be composted to fit the USDA Organic rules and/or to be safe to apply to a food crop, then the emissions that occur during composting can be assigned to the farm that uses it.  This is no different than assigning farms the footprint for the energy-intensive manufacturing of synthetic nitrogen fertilizers.

What Would Have Happened To This Waste If It Wasn’t Composted?

This is an important question. If you compost your vegetable scraps instead of sending them to the landfill, you are way ahead even if small scale composting has some greenhouse gas emissions (I’ve never seen a study on this).  This is because far more methane would have been generated in the land fill.   If manure is not composted but simply stored for a while and spread on a non-Organic, non-food crop like field corn (this is the normal scenario), there are still some methane emissions during storage.  Thus it is fair to deduct that storage-associated level of emissions from the footprint of  composted manure (it still comes out larger than for synthetic nitrogen).

What Would Be The Best Use Of The Waste Stream?

“Waste is a terrible thing to waste.”  Whether it is manure or some other organic waste stream (yard waste, food scraps…), there is energy potential in every ton, and it often has more economic and environmental value as a renewable energy than as fertilizer .  There are technologies like anaerobic digestion or fast pyrolysis that could convert this waste to energy and offset fossil fuels.

Conclusion

Composting definitely has its legitimate place in our need to deal with wastes.  Compost can also be very good for building soil quality.  It just isn’t a good way to provide nitrogen for crops.

You are welcome to comment on this site or to email me at feedback.sdsavage@gmail.com

Commercial compost image from Tie Guy II

Right and Left Agree: OK To Risk Starvation Of The Poor

(Originally posted on Red Green and Blue, November 22, 2010. For a complete list of Steve Savage's posts on various sites see this link)

The anti-climate-science politicians from the Right and the anti-technology activists from the Left are independently, but quite successfully, increasing the risk of malnutrition and/or starvation for the poorest people of the world.  This may not be their intended agenda, but it is the likely outcome from what they are doing.

Another food price spike looming

There are rumblings today of another "food crisis" like that in 2007/8.  There is every reason to believe that food shortages will become more frequent and severe over the next few decades of overall human population growth. (See map above for where projected population growth will occur).

By 2050 we will need between 50% and 100% more food.  This cannot come from farming new land - it needs to come from producing more on the land we already farm. Fortunately there are a lot of dedicated people striving to make that possible.  However, because of the enormity of this challenge, there will be shortfalls because of weather extremes or pest pandemics.  There will be times that food is too scarce and far more expensive.

For those of us who live in relatively rich countries, the risk is that our lives will be somewhat disrupted, but for the hundreds of millions of the world's poorest inhabitants, the risk is true suffering and even death (not to mention political instability, mass migrations...).

This risk is real and it is increased by the powerful forces that drive the  anti-climate-science agenda from the Right and anti-technology agenda from the Left.

How the right wing is increasing starvation risk

It is no surprise that the science behind something as complex as Climate Change carries some uncertainty and some disagreement among scientists.

Unfortunately, that normal feature of science has become fodder for conservatives who don't like the policy implications that come with the consensus conclusion: we have a problem, and we are likely the cause of that problem.

If climate change is real, we can expect to see a wide range of weather extremes and other basic shifts that will make food production even more challenging than it has always been.  If we do nothing (and the recent election results make that almost certain), we will eventually see exagerated food supply crises.

The greenhouse gas emissions are driven mainly by the rich.  The increased food insecurity will be felt by the poor.  If the anti-science Right is wrong about climate change, the risk isn't so much about "charismatic megafauna" like polar bears - it is about starving kids.

How the left wing is increasing starvation risk

There are a number of very influential environmental NGOs who have been quite successful at impeding the development of agricultural technologies.  They have done this with the aid of many academics, media, bloggers and celebrities.  In Europe this agenda has also been driven in the political realm by the Green Party. Their "achievements" to-date include:

• Blocking the commercial development of new GMO crops by driving major food companies to reject them purely for reasons of "brand protection." (Potatoes, wheat, sweet corn, sugarbeets..)
• Convincing most developing nations to adopt a European-like regulatory structure for GMOs, so that it is now unlikely that biotechnology will be developed in time to help feed the most rapidly increasing populations over the next 50 years (e.g. virus resistant cassava, drought tolerant corn for sub-Saharan Africa).
• Convincing most developed world governments to dramatically reduce their investment in agricultural development research that includes any technology component and attacking groups like the Gates Foundation for stepping in to fill that void.
• Using intensive litigation to make the cost of developing newer, safer and more effective pesticides prohibitively expensive.
• Pushing the EU to apply the "precautionary principle" to agricultural technology regulation.  This limits crop productivity in the EU at the same time that rich population is doing a "virtual land grab" for food imports that is equal to the land mass of Germany and growing.

All of these actions combine to slow the rate at which food production can be increased, and that increases the probability of shortfalls in the future.  Most of this anti-technology activism is again concentrated in the rich world which will be largely insulated from food insecurity.  The poor people they "protect" from technology will be the ones at risk of insufficient food.

Both sides can probably see how the other one is raising risk for the poor, but they seem to have difficulty seeing how they are doing the same thing in a different way.  In any case, these forces on the Right and Left are succeeding, and there seems to be little we can do about it.

You are welcome to comment on this site or email me directly at feedback.sdsavage@gmail.com.

(Global Population Growth Map from Lauren Manning)