Why We Need To Pay More Attention To The Role Of Landfills In Global Warming

By Peter Anderson

Landfills, the current destination for a majority of our trash, are a major source of methane.

Recent accounts that have filtered back to Climate Progress from Rio+20 suggested satisfaction with a World Bank Report concluding “Integrated waste management” (which purports to prioritize recycling over landfilling), is being implemented in the developed countries.

We have been left with the impression it is just the undeveloped world landfills still present a problem.

But, stripped of its window dressing, “integrated” is just bureaucratic speak for a blank check to the U.S. disposal industry. Sagaciously, the national firms duly consider all options, and then,\ select the one that is most profitable to them (other than in green cities that insist upon better than that). Morgan Stanley Dean Witter reports that the industry’s view is: “recycling has long been the enemy of the solid waste industry, stealing volumes otherwise headed for landfills … their most promising assets.”

Fortunately, one organization did not ignore the waste sector. In 2009, the Sierra Club undertook a year-long due diligence. Peeling back the onion layers, its technical experts found that industry’s claims – that their operators captured most of the methane generated in landfills, and that landfill-gas-to-energy (LFGTE) miraculously converted lemons into lemonade – were as bogus as the ethanol deceit. In fact, landfills were responsible for almost five times more GHG emissions than understood. Attempts to recover energy from inherently low Btu and dirty gas only made bad things worse.

Methane is so potent a greenhouse gas, even small leaks from major generators of methane are a huge concern – depending how much escapes.

Major volume of methane generated

Over the 100 years or so that landfills generate gas, methane equivalent to roughly 472 million tons of carbon dioxide will be generated from just one year of municipal trash in the U.S. That is a third more than from heating and cooling all of the homes in the country.

Most landfill gas escapes

The Intergovernmental Panel on Climate Change (IPCC) reviewed the waste sector in its 2007 Fourth Assessment Report. In reference to the industry’s claims, the Panel acknowledged the possibility that the best landfills might achieve very high capture rates when there is functioning gas collection and the site is sealed. But, of course, the best of the best has little to do with actual long-term impacts.

The IPCC pointedly noted that in contrast to the best operations, “some sites have less efficient or only partial gas extraction systems and there are fugitive emissions from landfilled waste prior to and after the implementation of active gas generation.” More importantly, it found most of the “fugitive emissions from landfilled waste [occurs] prior to and after the implementation of active gas extraction; thus estimates of ‘lifetime’ recovery efficiencies may be as low as 20%” – that is, most escapes.

Energy recovery makes a bad situation worse

Landfill-gas-to-energy (LFGTE) is said to be beneficial because that energy produced at the site can offset the need to generate power on the utility grid, along with emissions of carbon dioxide. If correct, LFGTE sites would provide a positive net benefit to climate efforts.

But, that puts forward the wrong comparison. Because methane is such a high octane warming gas, and because some methane escapes (even in the landfill industry’s goldilocks tale of gas collection efficiency), diverting the organic discards – which in landfills, and only in landfills, generate significant volumes of methane – is, EPA says, is always preferred.

For the waste that is already buried in landfills, diversion is no longer practical. However, as the Sierra Club’s year long investigation found, landfills operated to minimize fugitive gas have too few Btus to productively generate power. The operational changes needed to produce gas with enough energy value are significant: companies must augment moisture levels, shift gas production from the distant future to the present, and enhance the proportion of the gas that is methane. More gas is produced, more of which is methane, more of which escapes, all of which overwhelms the LFGTE’s benefits in CO2 reductions. A real live dispute at a New Hampshire landfill illustrates the irreconcilable conflict between gas collection and power production.

Landfills are the fourth largest source of GHGs

There are two major errors in how landfills’ greenhouse gas emissions have historically been accounted for: first, in outdated calculations of methane’s global warming potential (21× CO2 instead of 33×), and, second, overstated guesstimates of landfill gas collection efficiency.

Fixing them has significant implications for correctly assessing landfills’ responsibility for greenhouse gases.  If the wrong numbers are used, as done in traditional GHG inventories, landfills only appear to be responsible for 1.6% of total man-made emissions. However, when these mistakes are fixed, landfills climate almost 5× conventional inventories, representing 7.5% of climate changing gases.

This correction pushes landfills from the 11th largest contributor to climate change to the 4th, right after the very biggest ones: electricity generation, transportation and factories.

Contrary to the climate commandeers’ claims, landfills are, it turns out, among the largest sources of climate changing emissions, and even more so in the next critical 20 years when methane’s warming potential is more than 100× CO2’s.

Landfills are a major source of emissions. And we can’t allow for “climatewashing” that covers up that impact.

Peter Anderson is Executive Director of the Center for a Competitive Waste Industry.

20 Responses to Why We Need To Pay More Attention To The Role Of Landfills In Global Warming

  1. prokaryotes says:

    I wonder how much oxygen is depleted during the process of methanogenesis. And at the same time all these methane could be used as biogas to heat homes.

  2. prokaryotes says:

    If there would be something like action to prevent accelerated warmth and resulting more extreme conditions, we would immediately set up a program to generate biogas and/or biochar from all the waste. This is actually a win win situation.

  3. Merrelyn Emery says:

    A price on carbon applied at source is a huge incentive to innovation and sanity. Some of our Council tips were identified as among the top emitters attracting the penalty, causing a rush to change.

    However, prior strategies such as zero waste with multiple underlying supports such as specialized recycling centres can reduce the amount going into landfill dramatically, ME

  4. Mark Shapiro says:

    Knowing that waste contributes so much to AGW makes zero waste efforts more important, and also more valuable.

    Recycling (and of course reducing and reusing) is the key. Composting is also valuable. And then waste-to-energy need to improve. That will close the loop cleanly, and all but eliminate landfilling.

    But the goal — the only goal — is zero waste. Reading this article makes that clear.

  5. K Draper says:

    While I fully support the zero waste agenda, there is some interesting research going on to help contain the methane in existing landfills using biochar which will be interesting to follow.

  6. Post hoc says:


    I disagree that knowing how much landfill contributes to AGW makes zero waste more important.

    What it makes more important is zero degradebale organic carbon to landfill. From an emissions point of view, throwing PET or other plastics into a landfill does not contribute to AGW. It is a waste of resources yes, but plastic in landfill sits there and doesn’t do anything.

    We need to be realistic what is the actual problem one it trying to ‘solve’ with zero waste, it is about resource recovery and not AGW, because some waste needs to go to landfill.

  7. gus says:

    I support zero waste, but the REAL issue here is stopping the massively unnecessary consumption in the first place, especially of packaging and other stuff designed for single use.

  8. prokaryotes says:

    Or things which are desgined to only last a couple of times.

  9. Peter Anderson says:

    K Draper,

    There are several different proposals for enhancing the capacity of the layer on top of a landfill to oxidize fugitive methane as it transverses through the cover.

    While, by themselves, these tests do show an isolated capacity — in carefully controlled conditions — to oxidize methane, there are too many cross-currents and unintended consequences to put this forward as a solution to the inherent incapacity of gas collection in landfills.

    The primary complication with reliance on oxidizing covers is that this precludes the use of the more effective composite cover, which consists of a low permeable geomembrane (or plastic sheet like the ones used on flat rubber roofs) overlain with 2-3 feet of compacted soil.

    Unfortunately for any hope of widespread application of oxidizing covers, in landfills with composite covers, the gases generated only escape in high fluxes through cracks in the geomembrane or breaks in the seals between the cover and the vertical gas collection pipes, etc. Oxidation does not work in high flux environments. P. M. Czepiel, et al., “Quantifying the effect of oxidation on landfill methane emissions,” Journal of Geophysical Research (July, 20, 1996)., at p. 16,720.

    Bottom line: to maximize oxidizing covers also means forgoing the very type of cover that makes the best seal. And, research conclusively demonstrates that only gas collection systems with those tight seals can effectively capture gas (for the duration of those tight covers). One study by the landfill industry itself indicates that composite covers capture about 200 times more gas than the types of diffusion covers needed to oxidize. Goldsmith, “Methane Emissions from 20 landfills across the US using vertical radial plume mapping, 623 J. Air & Waste Mgt 183 (2012), at 195-6.

    That is the reason why more reputable proponents of these alternative covers acknowledge that there only real application lies in already closed and largely abandoned landfills.

  10. No doubt we need a whole rethink of how we view and deal with resources (aka waste). While in a perfect world, we may want to eliminate waste all together, we can probably all agree that given the current mindset, infrastructure, regulations and practices, this is highly unrealistic. That said, what we can do is eliminated the ‘concept’ of waste. Which is what the Construction Resource Initiatives Council was established to do, and the reason for the strategy behind its first action, Mission 2030. As buildings are the largest consumers of building materials and waste generators, the initiatives aims to eliminate construction, renovation and demolition waste to landfill by 2030. While it’s far from being the solution to the waste issue, it’s a great start that was recognized by the United Nations Environment Programme (UNEP) and a growing number of organizations. Mission 2030 will in fact be presented at the International Solid Waste Association Congress in Florence, September 2012 under the waste prevention program, and again at the International Sustainability Real Estate Forum, in Vienna, May 2013. A comprehensive approach to a complex issue…

  11. Mark Shapiro says:

    Correct. That’s why we say:

    “Reduce, reuse, recycle”

    in that order.

  12. Peter Anderson says:


    Yours is an excellent question. But, notwithstanding all of the excellent points raised above about the ambitious goal of zero waste, the immediate problem here surrounding climate change and landfills is much easier to get one’s arms around.

    That is because the methane at issue stems primarily from food scraps and yard trimmings, which, in a landfill, and only in a landfill, decompose uncontrolled under the anaerobic (oxygen starved) conditions that generates methane instead of CO2 and water.

    So all we need to remove for this step are those two items rather than everything. Diverting yard trimmings is ridiculously easy. Twenty two states have banned them from landfills, which works very well, especially when grasscycling is used in lieu of any collection, thereby reducing costs.

    Food scraps, while not as easy to divert, is eminently doable, as demonstrated by more than 120 cities in North America. That is done by adding another container for organic discards to be separately collected. Because so much is then diverted, including all of the stuff that rots, it is possible to reduce the number of trucks needed to collect the small amount of residuals, reducing net costs to a very practical level. For much more on how this is already happening, and how cities can build on the experience to expand the number of people composting, you can go to this report that we did for EPA on the subject for details:


  13. EDpeak says:

    Tried to find that juicy quote,

    ” “recycling has long been the enemy of the solid waste industry, stealing volumes otherwise headed for landfills … their most promising assets.””

    but the only link given, in does not include it…could you please include the link that does confirm this quote?

  14. Mike 22 says:

    page 2 of this gives the original source of quote

  15. Peter,

    please let me clarify. When I say we need to eliminate the ‘concept’ of waste, I am not suggesting that we need to eliminate everything, but rather the idea that ‘waste is waste’. As long as it is referred to as such, it will be treated as waste – with little value and who cares as long as it’s not in my own backyard type attitudes.

    But let’s take your food scraps and trimmings for a second, and let’s call them compostable, the mindset and dynamics start to change. Then let’s educate to enable the stakeholders and role players to bring a compostable facility to town, starting to reverse the vicious cycle in the right direction – reducing that nasty methane with its 6.5 to 56 times worst global warming potential than CO2.

    That said, as food scraps and yard trimmings are part of the residential stream, which is only 1/3 of the overall, we also need to look at the big items of the other 2/3 industrial, commercial and institutional waste. Unfortunately, depending on where you are, these are often not regulated by the municipality, but rather by regional and federal governments, and a big free trade issue.

    And based on our research, it is clear that with better decisions in the early stages of building and industrial design, life cycle impacts can be minimized. i.e.:
    in one study, it was determined that for every kg of drywall recycled, 24kg of CO2 could be averted

    In a 2003 Philadelphia project study, it was calculated that every square foot of materials diverted equated to the
    avoidance of 4.29lbs of GHGCE, 15.75lbs of GHGCO2 & 33,47BTUs.
    All that said, as the International Solid Waste Association concluded in their 2011 paper, there is no doubt that the waste industry has made great progress and that there are lots of tools to deal with the issue, the question is how. And while they and just about every organization seem to speak of integration, the building industry – the one most responsible for global warming (considering design, building and operations – still is far too fragmented. And that’s how we’re hoping to change things.

    Our municipality, as many others as you point out, already has composting (green bins), so now for us & many other regions, it’s time to address the other very complex 2/3 which is the IC&I waste stream. For me, it’s not so much a question of which should be a priority, but more one that questions why does every sector not see the role they have to play, and if it’s in parallel with others facing the same challenge, why not go at it together…

  16. AlC says:

    The bacteria producing methane are anaerobic, won’t be happy until other bacteria have consumed whatever oxygen is around.

  17. AlC says:

    Rapidly degraded organic material like food waste can be converted to methane within 30 days or so, too quickly for a landfill cap to be constructed to capture the escaping methane. For such material, it would seem suitable to digest it within sealed anaerobic digesters and capture the resulting biogas, typically approximately 60% methane/ 40% CO2, to generate energy to offset the energy needed for collection.

  18. AlC says:

    How many states have recycling requirements like California’s AB939?
    AB 939 mandated local jurisdictions to meet solid waste diversion goals of 25 percent by 1995 and 50 percent by 2000.

  19. Peter Anderson says:

    For markets with sufficient population to generate sufficient throughputs for scale efficiencies, and with the technical proficiency to manage a technology which is on the cusp of routine commercialization, you are exactly right. In those appropriate circumstances, digesters, especially wet digesters, have the additional attraction of more easily removing the kinds of contamination higher participation rates will generate.

  20. Robert Haverlock says:

    And, what about bio-digesters? How do they fit in and is it less likely to caputre enough energy and also leak copius amounts of nitric oxide and co2?