Why Claims About Reductions Of U.S. Carbon Dioxide Emissions Are Misleading

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"Why Claims About Reductions Of U.S. Carbon Dioxide Emissions Are Misleading"

by Kevin Matthews

A person — a public figure, member of the media, maybe even an international climate negotiator — could be confused about U.S. carbon dioxide emissions.

In August, 2012, the Associated Press reported this:

In a surprising turnaround, the amount of carbon dioxide being released into the atmosphere in the U.S. has fallen dramatically to its lowest level in 20 years, and government officials say the biggest reason is that cheap and plentiful natural gas has led many power plant operators to switch from dirtier-burning coal.”

Since August, the misleading meme of shrinking U.S. greenhouse gas emissions has been picked up and carried forward by a variety of respected sources. As recently as November 26, for instance, the Guardian reported on how the findings were influencing climate negotiations:

Greenhouse gas emissions from the US have fallen sharply in recent years, owing to the replacement of coal-fired power generation by gas in the US, following its widespread adoption of shale gas.

Jonathan Pershing, a senior negotiator for the US, said: “Those who don’t know what the US is doing may not be informed of the scale and extent of the effort, but it’s enormous.”

Given these claims, you’d think that there was solid information that U.S. greenhouse gas emissions have dropped. But the real story is somewhat different.

Back in August, the U.S. Energy Information Agency (EIA), part of the U.S. Department of Energy (DOE) that collects and reports certain energy-related data, posted an article centered on this graph:

That graph is labeled obscurely, but with partial accuracy, as showing U.S. “carbon dioxide emissions from energy demand.”

That’s the same as “carbon dioxide emissions from energy use” or “carbon dioxide emissions from energy consumption,” which is primary data collected by the EIA. It’s relatively easy to track in real time, since it’s essentially based on adding up the sales figures for coal, oil, and natural gas.

Therein lies the first layer of confusion. The EIA does not include biomass combustion energy, hydroelectric power, or true renewables like wind and solar in its main energy consumption figures. Except for biomass, there is little CO2 associated with the use of these clean energy sources.

So the EIA graph in the article should be labeled as U.S. “carbon dioxide emissions from fossil fuel consumption.” In fact, that’s exactly how the graph is labeled in EIA’s deeper technical reports. According to the most recent official EPA figures, carbon dioxide emissions from fossil fuel consumption represented about 79% of total U.S. greenhouse gas emissions in 2010.

Starting a tally of this U.S. fossil fuel use “grade inflation,” we can use these terms:

(CO2 emissions from fossil fuel use) + (CO2 emissions from all other energy use) = (total CO2 emissions from energy use).

The big headline on the EIA article adds another level of exaggeration. It says “U.S. energy-related CO2 emissions in early 2012 lowest since 1992.” Note the shift from “energy-use” CO2 emissions to “energy-related” CO2 emissions.

The headline is directly wrong because the underlying data does not include CO2 emissions from energy production and distribution such as flaring of natural gas, an increasing element in the U.S. EIA seems to use the this sloppy label regularly.

(CO2 emissions from energy use) + (CO2 emissions from energy production & distribution) = (energy-related CO2 emissions)

The headline also sets people up for another natural error. While CO2 is the biggest greenhouse gas, it’s not the only one. It’s common practice in adding up climate numbers to convert all the differing units of other greenhouse gases into CO2-equivalent values.

It’s tedious to always say “CO2-equivalent greenhouse gas emissions.” And pretty often, people just say “CO2 emissions” when “CO2-equivalent emissions” is what they really mean.

That’s just a little slippage in our language, but it has big implications for the numbers.

(energy-related CO2 emissions) + (non-CO2 energy-related emissions) = (energy-related greenhouse gas emissions)

Missing Methane

The biggest energy-related non-CO2 emissions are methane — and that’s huge.

Estimates of energy-related methane emissions are in flux, as traditional industry numbers are being looked at more closely. Current research, in line with a recent NOAA report, suggests under-reporting by the fossil fuel industry may be on the order of 2 percent of natural gas used, suggesting total methane losses on the order of 4%. Since methane is about 21 times more potent as a greenhouse gas than CO2 (in the time frame of a generation), we can multiply (4% methane leakage) x (21 times GHG impact compared to CO2) = 84%. That shows that methane emissions from the natural gas system may have a CO2-equivalent greenhouse gas impact roughly comparable to the GHG impact in CO2 from burning the gas. While the methane emissions may prove to be somewhat smaller, there’s little doubt they are significant.

This is part of the picture described by guest bloggers Shakeb Afsah and Kendyl Salcito in the Climate Progress article “Shale Gas And The Overhyping Of Its CO2 Reductions.”

By leaving out methane, and other things, the EIA data really only describes one specialized slice of emissions. It’s a big slice, but not one to freely generalize from.

Because renewables are missing from the EIA data, which has been widely and inappropriately generalized, it’s all too easy for pundits and reporters to simply compare the coal curve and the natural gas curve against the (baseless) overall conclusion of dropping emissions, and then call out lower natural gas prices as the cause of U.S. progress — thus leaving out the significant growth of renewables. But that’s another story.

Ultimate Confusion

As noted above, it’s apparently been easy for analysts and media alike to take the EIA information to the final level of misinformation, trumpeting that CO2 levels have fallen to their lowest levels in 20 years or that greenhouse gas emissions have fallen sharply.

The claim is wrong, because to get to greenhouse gas emissions overall, all the non-energy-related emissions sources also need to also be included. To summarize and complete the equation:

EIA data: (CO2 emissions from fossil fuel use)
+ (CO2 emissions from all other energy use)
+ (CO2 emissions from energy production & distribution)
+ (non-CO2 energy-related emissions)
+ (all non-energy-related greenhouse gas emissions)
= total greenhouse gas emissions

Methane, flaring, and biomass emissions not included in the primary EIA numbers mean those numbers don’t fully reflect energy-related GHG emissions.

According to the official U.S. GHG emissions inventory, the non-energy-related emissions (from agriculture, logging, other land use changes, etc.) represent another ~20 percent of the total, on top of the ~80 percent of GHG emissions that are directly energy-related.

EPA to the Rescue

The EIA used to actually calculate and report its own U.S. total greenhouse gas emissions numbers. That EIA overall GHG inventory was discontinued in 2011, due to mid-year budget cuts, according to an EIA source. However, the agency has never been the source of the official U.S. inventory.

The official U.S. greenhouse gas emissions inventory has been produced for many years by the EPA, following detailed international reporting protocols. It’s presented to the United Nations every April, in a careful and fairly hard-to-read formal report.

The most recent official EPA inventory, reported in April 2012 and showing total U.S. emissions for 2010, shows our emissions going up that year:


The current EPA inventory report shows total U.S. greenhouse gas emissions for 2010 up 3.2% over 2009 emissions, with an average annual growth rate from 1990 through 2010 of 0.5%. It’s hard to say what increase or decrease the U.S. inventory for 2011 will show, when the EPA releases it in April 2013, or what the inventory for 2012 will show when it comes out in April 2014. Unless someone is prepared to duplicate the EPA’s work, and do it faster, we can expect to wait for those numbers.

Bottom Line

U.S. major media and others have been trumpeting a false meme of declining U.S. greenhouse gas emissions, spinning off from EIA data that actually shows a much narrower trend.

While the primary EIA data represents a large, very specific piece of the overall U.S. emission inventory, it’s fundamentally misleading to inflate its importance. Nonetheless, this seems to have been done regularly by the EIA itself, and to an even greater degree by downstream users of EIA information.

In the past, EIA produced an overall emissions inventory. Because energy consumption is easier to collect and report on quickly than other types of emissions, they continue to produce reports including U.S. CO2 emissions from energy use, which the EIA releases at a pace tantalizingly close to real time.

No doubt it’s frustrating to media and officials who love to report on realtime score cards, but the only official U.S. greenhouse gas emission inventory comes from the EPA. It takes a while for all the data to be collected and complied — and impatience is no reason to misrepresent the data available.

In any case, year-to-year ups and downs in U.S. emissions are not very meaningful relative to the scale of the climate mitigation challenge we face together. In the U.S., we need to be planning and faithfully implementing, in every sector of our economy, in every government, agency, and large organization, roughly 5% reductions in total greenhouse gas emissions, every year, year-on-year, for the rest of our lives.

And no blip in annual emissions, whether actual or invented, is going to rescue business-as-usual from this fundamental need for real climate action.

Kevin Matthews is Editor-in-Chief of Architecture Week.

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24 Responses to Why Claims About Reductions Of U.S. Carbon Dioxide Emissions Are Misleading

  1. And don’t forget those emissions we export by shipping coal overseas. Less coal use in the US has led to greater US exports and lower coal prices for other countries, thus increasing coal use worldwide.

  2. Peter Anderson says:

    The conversion for methane on a carbon dioxide equivalent basis is badly out of date. The 21x GWP for methane dates back to the early 1990s, which did not include many of methane’s indirect warming effects. The latest data from NASA is 33x CO2. And that is when the conversion is done on a 100 year basis. When concerns turn to near term irreversible effects for example in the Arctic, the 20 year conversion is 105 times CO2. Note that EPA continues to incorrectly perpetuate the very badly out of date estimate because, it avers, it wants to maintain a consistent time series. But, that makes no sense in that one can have a back-table with that consistent time series for those that want that. But, for decision making today we need the best estimates available, which is 33x (long-term) and 105x (near term). Solid assessments ought not perpetuate EPA’s inexplicably bad policy judgements in the national inventories.

    • John Atkeison says:

      Please give us references for your important information!

      • John McCormick says:

        Yes, Peter. Take a moment and provide some references. Those are important values you presented. Thank you.

      • wili says:

        Schindell et al. 2006

      • wili says:

        Oops, that should be 2009. I should learn not to trust my aging memory for these things. Here’s the full citation to the article, mentioned (and critiqued–unfairly, in my view) in the piece linked by Peter Anderson below:

        Drew T. Shindell, Greg Faluvegi, Dorothy M. Koch, Gavin A. Schmidt, Nadine Unger, and Susanne E. Bauer, “Improved Attribution of Climate Forcing to Emissions,” Science 326 (5953) (October 30, 2009): 716–718.

    • Your point is well taken. Because the next few decades are critical, it’s the 20 year global warming potential for methane that’s the important one for policy purposes, and that one is much larger than the 100 year potential.

  3. It is a good point that all GHGs need to be counted.

    At the same time, I do think that declining CO2 from fossil fuel burning is a worthy story and a real improvement in the direction USA is heading.

    And even the EPA chart you use showing full GHG shows 2010 at a level similar to 13 years ago. Not bad either.

    Obviously these trends aren’t enough by a long shot. But they might be a sign of the required plateau and followed by bending the curve down.

  4. Bob M says:

    Kevin, you make a good point about methane flaring and production-related GHG releases. However, the added emphasis on fossil fuels is warranted because they’re not part of the current organic carbon cycle like biofuels, agriculture etc. They represent a net increase in our biosphere carbon, and for all practical purposes an irreversible one.

    The non-inclusion of renewables is only significant for those who are tempted to go the extra step and attribute a drop in CO2 to other causes, such as market factors.

    Report-parsing aside, it’s fairly clear that any attempt to halt increases in atmospheric carbon starts with leaving fossil fuels in the ground.

    • I completely agree:

      “…It’s fairly clear that any attempt to halt increases in atmospheric carbon starts with leaving fossil fuels in the ground.”

      As opposed, for instance, to the idea that we’re making good progress by substituting gas for coal.

  5. Daniel Kirk-Davidoff says:

    Please read this analysis of the relative importance of methane: http://schraglab.unix.fas.harvard.edu/publications/128_Schrag.pdf

    What we should really be concerned about is the cumulative greenhouse emissions, because that’s what will determine how bad things get. Because of methane’s short lifetime, and the earth’s longer response time to radiative forcing, its impact on temperature is smaller than its impact on forcing. If methane can help us shut down coal burning, we should value that.

    • Peter Anderson says:

      Yes, and no.

      While it is true that the methane emitted today is short lived: (1) discounting the gas for the fact that it does not persist ignores the potential irreversible damage it may inflict before it oxidizes; and (2) the fact that this year’s methane is likely gone in 10-15 years needs to be balanced against whether future methane emissions replace it, even though it will not accumulate in the way that long-lived GHGs like CO2 will.

    • Worth reading this: Wigley, Tom. 2011. “Coal to gas: the influence of methane leakage.” Climatic Change. vol. 108, no. 3. pp. 601-608. [http://dx.doi.org/10.1007/s10584-011-0217-3]

      Cumulative effects are important, but the transient effects related to methane’s higher warming potential in the 20 year time frame are also critical.

    • Joan Savage says:

      Schrag makes the familiar, and widely acceptable, argument that a carbon tax would be helpful in closing down coal-fired plants.

      However, some of his other assumptions are out of date. He assumes, without actually saying it in so many words, that methane use will have enough less net damage to be a suitable fuel for what he thinks is a hundred-year transition.

      Earlier comments by Peter Anderson and willi drew attention to Shindell et al 2009, which came to the conclusion that methane has a much bigger role in forcing, due to its Aerosol Interaction Effects (AIE), than had been previously estimated.

      Also, a hundred-year time line for transition should be modified to reflect how climate change effects have already ramped up, above estimates.

      Schrag’s view could have been seen as best management practices as recently as four years ago. Keep the good stuff and ditch what is out-of-date.

  6. Thanks for this article. I agree, given EPA data provided here, that CO2 reductions from energy use per the EIA is outpacing (so far) the EPA accounting. But, not to a degree that the EIA data is *misleading.* For example, your EPA data starting with the 2005 year shows a 5.3% reduction whereas the EIA data for the same period shows a 6.5% reduction. That’s a meaningful difference, and worth noting. But, the reductions to come in years 2011 and 2012 will accelerate, based on the trend from the EIA.

    But let’s get to a larger problem, here. Virtually no *federal* government policy is to be credited with the trend lower in US emissions. It is almost entirely down to classical pricing and economics, in which natgas has replaced coal and high oil prices have taken US car drivers off the road. Even the buildout of public transport and the flow back to publi transport by a public looking to flee high gas prices is a phenomenon driven by cities and states.

    In other words, the Obama Administration will surely take policy credit for reductions in emissions when the great recession, natural gas, and high oil prices are mostly the cause. How fortunate an outcome for a Democratic Party and Admin that really has no stomach at all for tackling climate issues.

    The risk here is that if the US returns to higher levels of growth (which is unlikely but possible, imo) then no meaningful set of federal policy will restrain the resumption of emissions. Yes, many cite cite a basket of small measures taken by the Obama Administration over the past several years. But frankly, imo, they are minor.

  7. The limits to growth study in 1972 pointed out that pollution would increase as we passed peak consumption of resources (not only oil).

    As long as people want to use fossil fuels, as long as we ship food across time zones and borders, as long as global aviation is a key part of the global economy, as long as economic “growth” is desired and population growth accommodated, we will still use fossil fuels, regardless of their climate impacts, at least until they are no longer available.

    A solar economy would be a smaller, localized, steady state economy, not a growth economy that is based on compound interest with fiat money loaned into existence. It’s probably a reason why governments (and philanthropic foundations that fund environmental groups) focus on “reducing carbon footprints” instead of a holistic approach that included how we will cope with the downslope of fossil fuel production. Oil, coal and gas, among other resources, allowed human population to zoom from one to seven billion.

    I have yet to come across any “climate” activists who suggest the trillion dollar (plus) highway expansion plans should be immediately stopped. A few oppose a road here or there, but who dares to say highway expansions should end given the end of cheap oil and the start of climate chaos? Certainly none of the Democratic politicians claiming we can supposedly stop climate change nor the climate groups who are often funded by the nice people at the Rockerfeller, Ford, Pew (sunoco) foundations and their friends. I’m sure their oily hearts have the best intentions when they provide the budget for these organizations.

    Green growth is an oxymoron.

    Using solar electricity for two decades taught me that living on our solar budget could not power increased overconsumption. That’s the real inconvenient truth.

    Mark Robinowitz

    Connected Dots

    Peak Oil and Climate Change

  8. “Awareness of Climate Change by the media and general public is obviously running well ahead of awareness about Peak Oil, but there are interesting differences in this general pattern when we look more closely at those involved in the money and energy industries. Many of those involved in money and markets have begun to rally around Climate Change as an urgent problem that can be turned into another opportunity for economic growth (of a green economy). These same people have tended to resist even using the term Peak Oil, let alone acknowledging its imminent occurrence. Perhaps this denial comes from an intuitive understanding that once markets understand that future growth is not possible, then it’s game over for our fiat system of debt-based money.”
    – David Holmgren, co-originator of permaculture, “Money vs. Fossil energy: the battle to control the world,”
    http://www.holmgren.com.au/DLFiles/PDFs/Money_vs_Fossil_Energy.pdf

    David Holmgren, the co-orginator of permaculture, is author of Future Scenarios: How Communities can adapt to Peak Oil and Climate Change.
    “Economic recession is the only proven mechanism for a rapid reduction of greenhouse gas emissions … most of the proposals for mitigation from Kyoto to the feverish efforts to construct post Kyoto solutions have been framed in ignorance of Peak Oil. As Richard Heinberg has argued recently, proposals to cap carbon emissions annually, and allowing them to be traded, rely on the rights to pollute being scarce relative to the availability of the fuel. Actual scarcity of fuel may make such schemes irrelevant.”

    • Your belief that fossil fuel scarcity is the only way to reduce use of such fuels is incorrect. In fact, the amount of such fuels potentially available to us makes it unlikely that resource constraints will serve as a check on emissions: http://thinkprogress.org/climate/2012/04/14/464584/why-fossil-fuel-abundance-is-an-illusion-unless-your-goal-is-humanitys-self-destruction/

      As an analogy, consider salt. In the old days it was a valuable strategic commodity, because it was the best way to preserve meat. Now we buy a pound of it in the supermarket for a dollar. What happened? Commercial refrigeration put salt in its place. In other words, technology allowed us to move past salt. We need to do the same thing with fossil fuels–turn them into salt, in Jim Woolsey’s phrase.

      • Joan Savage says:

        I like the analogy to salt as commodity, but I come from the Salt City, Syracuse, that has a history with salt that could be a reminder or a warning.

        As salt waned as an essential food preservative in the 1800s, the Solvay Process was introduced to the area, and salt became an ingredient in synthesizing many other chemicals, including the raw materials for plastics.

        Salt mines today are still busy supplying the demand for raw material for those chemicals.

        Weaning off petroleum and coal as sources of energy would be huge and is the main goal.

        I just doubt if humans will grow weary of the other uses of coal and petroleum, such as sterile food packaging, medical bubble packs, spandex, lycra, computer casings, etc. – at least not anytime soon.

      • Love your salt analogy but unfortunately it cannot be applied to oil. The 6 GJ of energy in a barrel of oil makes petroleum a kind of super substance of energy density. The labor represented in that energy is useful, to say the least. Do you think that humans will choose to turn their back on such energy density, when no comparable substitute exists? I agree, we can decide to reorganize, re-scale and reoptimize our lives. We can choose different goals that don’t require high-powered energy. But I see no evidence humanity will choose to do so willingly. Limits are not bad. In fact, our ability to break past limits is part of our unique ingenuity but sadly has also delivered us to the Anthropocene. As you know, a planet where we are in control is both exciting but scary. And so to say we will move past high powered energy sources is to say we will choose, willingly, to be good stewards of the earth. I’m not betting on that, but it’s my hope.

      • I’ve used solar electricity for over twenty years, it’s great but it’s not going to replace our current consumption (pun intended).

        We use fossil fuels because they are more energy dense. Relocalizing food production is more reasonable than pretending solar and wind technologies will enable food shipments across time zones and international borders. The only solar powered planes we are likely to see will be drones, not Boeings carrying vacationers for winter holidays in the tropics.

        The failure of most of the climate movement to recognize physical reality is part of the reason why the climate warnings were not heeded.

        I’ve heard Mr. Woolsey speak in person, sorry I’m not impressed with this warmonger. He did mention thermal depolymerization in his speech, a euphemism for turning animal fat into fuel. Soylent Oil. I’m not joking.

        • Also, the recent claims the US has so much oil and gas we will be “energy independent” reminds me of Josef Goebbels, who said a Big Lie was easier to sell than a small lie. Fracking for natural gas is not only toxic, it has a sharp decline rate and the bubble is starting to burst. The Bakken fields of North Dakota also have similar decline rates. The shales of Utah and Colorado are unlikely to be mined much because they are not oil and would require more energy to process than they contain (and a lot of water, too). US oil production peaked in 1970, just as M. King Hubbert predicted in 1956. Conventional natural gas extraction peaked in the US in 1973. The Earth is round and therefore finite.

  9. jonesey says:

    First, Mr. Matthews is right that we need to implement major reductions in GHG emissions every year, on the order of 5% or more.

    Second, if you look at the EIA graph and the EPA graph, you’ll see that they are roughly correlated with one another. I’ll let someone else do the regression. If you assume a perfect correlation and extrapolate the EPA graph to 2012, you get GHG emissions at a level that matches 1993.

    So if the fundamentals have not changed, the headlines have been substantially correct about the GHG emission reductions (although not about the fuel-switching, as shown in the excellent Climate Progress article linked above).

    If something fundamental *has* changed, then Mr. Matthews is right to point out the differences between CO2 emissions from electricity consumption and overall GHG emissions. The one thing that I believe we will find has changed is leakage from fracking sites. I believe that there is much more methane being emitted directly into the atmosphere than there has been in the past.

    One more note: If we assume that the 2012 EPA graph will show about 6300 Tg of CO2 equivalent in 2012, which would match the EIA graph, that’s still only a 13% reduction from the 2007 peak, that’s only a 2.7% year over year reduction. And it’s still not at the magical “1990 levels” of the Kyoto Accords, let alone below those 1990 levels. We need to do much better, and quickly.