Thinking in terms of renovated bungalows, not megatons.

Greenhouse gas emissions are an abstract concept for most people. Ask a sample of Canadians what Canada’s annual GHG emissions are, and you’ll likely get a very broad range of answers (they’re about 750 million metric tons (Mt) per year).

The figures are so abstract that errors like Gasland producer Josh Fox claiming that Canada’s oilsands emit 36 Mt of GHGs per day go unnoticed by many – likely because they don’t have the context to catch the mistake rather than because they don’t care about the exaggeration. If you’re one of those people who didn’t catch the error, 36 Mt per day is about half of the world’s total GHG emissions, while oilsands emissions are about 40 Mt per year.

I am guilty of this abstraction myself – I deal in megatons all the time, whether it’s talking about carbon capture and storage, oilsands, or just about anything else I do – and I don’t often stop to think about the scale of those numbers. I decided to do something about this, using the example of Keystone XL.

The Keystone XL pipeline has been the source of a great deal of controversy, much of it centered on how best to assess the net increase in GHG emissions from building a new pipeline to deliver oilsands crude to the Texas Gulf Coast. The US State Department puts the net impact at between 3 and 20 Mt per year. The EPA puts the number about 20% higher, while my own back-of-the-envelope calculations put the net impact at no more than 28 Mt per year.

Since climate change is a global problem, my first reflex is often to consider impacts in terms of percentage of global emissions. Global emissions are just about 30 billion metric tons, or 30,000 Mt, which means that the potential increase due to the Keystone XL pipeline ranges somewhere between one tenth and one hundredth of a percent – either way, it’s a small number on that scale.

What would happen if you brought those numbers closer to home – closer to units to which we can relate? To do this, I decided to think about home retrofits, and specifically the question of how many houses you would have to retrofit (over and above those which would be retrofitted anyway) in order to offset the net increase in GHGs due to Keystone XL.

Under the ecoEnergy Retrofit program, Canadian homeowners can apply for a reimbursement of some of the costs of energy-saving home improvements as long as they have an energy audit performed before undertaking the renovations. NRCan reports that the average audit recommended actions which would lead to predicted GHG reductions of 3t/yr. Since it is generally the case that realized energy savings don’t match predicted energy savings as a result of households taking on fewer renovations than recommended or increasing the use of more energy-efficient products (the rebound effect), let’s assume that each retrofit actually leads to savings of 2t/yr. Further, assume that those savings last for 15 years, by which time the house would have been retrofitted anyway. Under these simplifying assumptions (adjust as you see fit), each retrofit leads to 30t of cumulative emissions reductions. The estimates won’t be perfect, but the order of magnitude will be right. Now, let’s put those two numbers together.

Assuming the Keystone XL pipeline is in service for 50 years, and that the net GHG emissions impact is in the middle of the range given above (15 Mt/year), this implies that you would need to retrofit 500,000 homes per year on average over the lifetime of the pipeline to offset the impact – about one house per minute for 50 years.

Now, 500,000 home retrofits seems like a big number, but it needs some context too. The ecoEnergy Retrofit Program financed approximately 225,000 renovations in the 2010-2011 fiscal year, but it’s likely true that many of those retrofits would have occurred in the absence of the program – the so-called free riders on the subsidy. In order to generate 500,000 retrofits per year over-and-above those which would otherwise have occurred, the program would likely have to finance at least twice that many and probably more – likely a 5-fold expansion of the current program. Given the current program costs $400 million per year to run, you’d likely need an additional $2 billion in retrofit subsidies to offset the GHG impacts of the Keystone XL pipeline.

When you think of the impacts that way – in terms of one renovated 1960’s bungalow like my own every minute – it puts a whole new perspective on the scale.

31 responses to “Thinking in terms of renovated bungalows, not megatons.”

  1. Surdas

    That’s an interesting calculation. The actual numbers are so obscure that they’re virtually meaningless. That’s the funny part about Fox’s error. He probably just got the units mixed up, but ultimately it doesn’t matter because nobody (except people who do this for a living) has a clue what 36Mt/day or /yr means.

    However, I don’t think that considering impacts of a single project (even a major one such as this) as a percentage of global emissions is particularly helpful. No project is going be more than a tiny fraction of a percent of global emissions – for obvious reasons. So what does that tell you?

    I think the one valid point that opponents of the pipeline have is that it’s a step in the wrong direction. A large part of the difficulty in reducing emissions is existing infrastructure, so adding a huge piece of infrastructure that will add a chunk of demand for oil sands bitumen seems like a big step in the wrong direction. The calculation of ppm CO2 locked in the entire oil sands or coal deposits of Alberta is not entirely pointless, because it tells you that unless you leave most of it in the ground, we’re going to be in big trouble. And it’s very difficult to leave anything in the ground – just look at asbestos. Certainly, increasing production with no regulation of GHGs isn’t looking good. So, it’s not the direct “What’s the Mt/yr?” it’s the more strategic “How are we going to get where we’re going if we’re moving in the wrong direction?”

  2. bill mckibben

    this is a fascinating calculation, and for the reason surdas points out: trajectory.

    because a different way of saying it is: you could retrofit a house every minute for the next 50 years, and that would be undone by running this one pipeline (not to mention the others that will surely follow if we go for this stuff bigtime). many thanks for putting it in a whole new light


  3. Robert McClelland

    The obvious flaw is that at 500k homes per year you’d run out of homes that needed to be retro-fitted in just a few years. The second obvious flaw is that retro-fitting homes is part of the strategy to reduce ghg emissions. If it’s done merely to offset growing tarsand emissions then you won’t achieve any reduction at all.

  4. Robert McClelland

    As far as putting context on units goes, it’s a bad idea. It’s better to stick to actual measurements and educate the public on what those measurements mean.

  5. Alan Nogee

    I agree with the above 2 comments. Andrew, along with Michael Levi, have done a valuable service identifying some of the errors and exaggerations of pipeline opponents (with whom I ultimately agree for the same reason as Surdas above).
    Unlike deniers, climate hawks cannot afford to be cavalier with the facts.

    But home retrofits aren’t valid points of comparison, in my opinion, because they are a relatively early and cheap source of reductions that already have to be fully tapped–along with much more expensive mitigation options–to reduce EXISTING GHG emissions by any amount, never mind to the 80%+ level of reductions most scientists think will be needed by mid-century. So the additional cost of offsetting this one NEW project (not that the author is proposing that as policy) would likely be much higher.

    Aside from the cost issue, the illustration may make the point that the pipeline itself would not be as catastrophic as many of its opponents make it appear. But a 2-5 x expansion of Canadian retrofits is a very large expansion, just to offset this one project. If anything, it reinforces the point that any new large emitting project significantly raises the burden of reducing already-much-too-high-existing emissions.


  6. Mary

    So how about posting some real math and real production numbers on wind turbines, not just in terms of their pitiful energy production, but also in terms of how little GHG they prevent?

    And what about NASA’s most recent news that measurements from space, not computer modeling but actual studies, showed that the computer models used to terrify the world about GHG emissions are WAAAAY off?

    These may be inconvenient truths to add to the argument for Global Climate Change, but they must be considered.

  7. Michael Noble

    I really enjoy reading your stuff Andrew, and it’s nice to come to your blog and see comments by @BillMcKibben and @alannogee. Seems like Twitter has been a very good tool for you getting your thoughts out of academia’s ivory tower, and onto the street.

    I too much prefer the “wrong direction” metaphor instead of the “small contribution” frame. But I love social math as a communications tool, and intend to quote your analysis of 1 bungalow a minute for 50 years tomorrow in a talk I am giving at the UofM lecture series.

    Keep it up.

  8. Mariel Escobar

    Josh Fox has already gone on record to correct this SINGLE piece of disinformation presented in the video. Regardless of his mathematical/statistical error, we should ALL be grateful to him for bringing this extremely dangerous threat to public health to light!

  9. Global Climate Disruption Discussions - Page 10 - Talk Delaware Online

    […] – that's about one house every minute. That's a lot of carbon that we just can't afford. Thinking in terms of renovated bungalows, not megatons. andrewleach.caGreenhouse gas emissions are an abstract concept for most people. Ask a sample of […]

  10. Jack Dunn

    Often the significance of large numbers is nearly impossible to grasp. Consider the distance to the moon as a way to illustrate the enormous quantity that the number 1 billion represents.

    238857 miles to the moon * 5280 feet/mile = 1,261,164,960 feet to the moon.

    Assuming that when you are walking your average stride length is 1.26 feet then with each step you have traveled 1 billionth of the way to the moon. After a billion footsteps you will be there!

    Tying this to your figure of 30 billion metric tons, it becomes equivalent to walking to the moon and back 15 times.

    Also consider that the concentrations of CFCs in the atmosphere are measure in parts-per-trillion PPT. As a point of interest, atmospheric concentration of CFCs as of 2000 was approximately 250 PPT. This is only one quarter of a footstep to the moon. It is astonishing to think that such small quantities of these substances have had such a profound effect on the ozone layer.

    We need to stop trivializing these big numbers and somehow realize that pouring billions of tons of CO2 into the atmosphere makes a very big difference.

  11. Holly Stick

    What do you think of this statement by Ezra Levant:

    “…Normally, Islamic extremists focus their hatred on the Great Satan — the United States. But Canada is now an enemy of the Saudis, too. Because we’re competitors to them for oil. Within ten years, the oilsands could totally replace Saudi exports to the U.S…”

    I’m interested in your opinion of the last sentence; the political BS is obviously nonsense.

    He also mentions Melissa Blake, and I doubt that he has ever asked her how she felt about her name being used for his crass comments.

    1. Holly Stick
  12. Rundle in NYC

    Interesting that noone is talking about the cost to renovated all those bungalows.

    Figures — hosers can’t use a calculator.

    If you really want to offset the XL incremental emissions, why not just buy the offset? Its a whole lot cheaper than renos and you don’t need to get June Cleaver on-side for the renovation

  13. Holly Stick

    Hi Andrew. Do you follow Mike De Souza’s reporting? You definitely should. His latest article demonstrates (in my opinion) that we cannot believe assurances by the Government of Canada about pipeline safety:

    He doesn’t tweet as much as some, but his feed is well worth following:!/mikedesouza

  14. Paul

    I agree that the tar sands help contribute massively to pollution and global warming. At the same time the tar sands were not created by mans indiscretion but by nature. Hydrogen production is the only solution to substantiating world economic stability without stop global warming and major pollution.Hydrogen though the most abundant element in the universe; but it is hard to manufacture, distribute and in need of time and project funding. At this time a non-polluting method to having hydrogen vehicles with filling stations is still a long ways away and still leaves without a good method of not creating more pollution, global warming and Global stability . Today September 22, 2011 the whole world is in economic chaos. a Peoples jobs, and countries abilities to stabilize economies are at risk. today shows we are really a global community. Other countries who’s pollution laws are lax and support terrorism or inequalities to humans are not as resolute as Canada’s. We( the whole world ) unfortunately are still a slave to oil and its detriment to maintain economic stability. Though your blog and articles are very factually correct, they do not solve the whole problem within this global communities in focus. I believe that cleaning up the tar sands with recycling of water and collecting the other byproducts that pollute is the only short term good solution at this time. With this in mind; better time and money spent would be to focus on a quicker and larger research program funded by oil companies, governments, investors, and people like yourself to lead this research. You are very influential, extremely knowledgeable, and connected to other Universities. Through sponsorship programs for Multiple Research and Development Programs your blog would create a faster, more positive, and maintain stability in these very difficult economic times. The average Albertan/Canadian who only knows oil as jobs and a way to keep their livelihood. They would be more supportive and may even donate money to your cause. You would also be spearheading Canada as a country finding solutions while they walk a tight rope between keeping the economy running and internationally doing the right thing in global warming issue. It is obvious you are a leader and people listen to you. What we as Canadians need to see is that we can lead in our solutions with global issue in mind.

  15. Patrick

    Hope I got the arithmetic right (I assumed metric tons) …

    Alternatively, if it’s 15MT/year, and the average car emits 5 metric tons of CO2 per year, then offsetting would require decreasing the total number of cars on the road by about 3 million per year, every year.

    According to wikipedia, there are about 256 million cars in the US. So in 2061 the total number of cars would be about 106 million. Alternatively, there could be zero registered vehicles in Canada and 130-odd million in the US.

    (Emission data from here:, care data from a sidebar here:

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