Carbon Emissions By the Construction Industry

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Carbon Emissions By the Construction Industry

A new book addresses greenhouse gas emissions associated with building materials manufacturing and construction

Posted on Mar 9 2018 by Martin Holladay
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Burning fossil fuels or using electricity results in carbon dioxide emissions (unless the electricity is produced by photovoltaics, wind, or another renewable energy source). Since CO2 emissions cause global climate change, environmentally conscious builders aim to build energy-efficient buildings.

Having an energy-efficient home is good for the homeowner, of course, but homeowners aren’t the only ones who use energy. Builders and building materials manufacturers also use energy. There are significant CO2 emissions associated with the energy required to produce building materials and build buildings — energy referred to as the “embodied energy” of the construction project. (For more on embodied energy, see All About Embodied Energy.)

There are two types of energy associated with a building over its lifetime: embodied energy and operating energy. For a well-insulated efficient building, embodied energy may amount to between 15% and 50% of the building’s total lifetime energy use.

If you are an environmental activist interested in addressing climate change, you’re probably aware of the following two facts:

  • In order to prevent an irreversible change in the planet’s climate, humans have to make drastic reductions to our CO2 emissions within the next 15 to 20 years. If we make these changes in 25 or 30 years, the changes will come too late to save the planet.
  • Embodied energy is “front loaded.” If you are building a house in 2018, all of the embodied energy gets burned this year, which means that all of the CO2 associated with that embodied energy is going into the atmosphere this year. Even if the building is efficient to operate, that operating efficiency won’t matter much if the front-loaded energy associated with the building’s construction helped doom the planet.

In short, for anyone concerned about climate change, embodied energy really, really matters.

What is “embodied carbon”?

A recently published book, , attempts to address the issues of embodied energy and the CO2 emissions associated with the construction industry. The book’s chief author is Bruce King, a member of the GBAGreenBuildingAdvisor.com Advisory Team during our early years. The New Carbon Architecture includes several chapters written by other contributors, including Chris Magwood, Larry Strain, and GBA blogger Ann Edminster.

The book’s authors are aware of the front-loading problem, noting that “carbon emitted today has much, much more impact than carbon emitted after 2050.” The book also notes, “We need carbon reduction strategies that have a positive payback within a 10- to 15-year time frame, or we should look for other strategies.”

So how do we figure out ways to build buildings without emitting much CO2? According to the book’s authors, we first have to understand the meaning of “embodied carbon.” But “embodied carbon” is a slippery concept, and I’m not convinced the term is useful.

To me, it’s easier to think about greenhouse gas emissions than embodied carbon. We start with the premise that builders want to avoid releasing CO2 and other greenhouse gases into the atmosphere. We know that most (but not all) forms of energy are associated with CO2 emissions. In theory, a residential contractor could power all of his or her electric tools from a portable PVPhotovoltaics. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. array mounted on a trailer, and could thereby claim that the electricity used to operate the power tools were only minimally associated with CO2 emissions. So the source of the electricity matters.

More importantly, we need to look at how much energy was used to create the specified building materials. For example, the embodied energy in a steel-framed building includes the energy required to make and deliver the steel. In almost all cases, there will be CO2 releases associated with steel production and delivery.

What about a wood-framed building? Energy is used to harvest wood, operate a sawmill, and deliver lumber to a job site; in this way, wood framing resembles steel framing. But a wood-framed building also “sequesters” carbon (at least until the building is demolished). Is this temporary sequestration of carbon good or bad for the planet? Suffice it to say that the answer is, “it depends” — and the calculation isn’t simple.

Most builders are probably unsure whether it’s a good idea or a bad idea to pack a building full of carbon (for example, by using wood framing, straw bales, and cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection.). Do we want to try to use as much lumber as possible in our buildings, thereby “sequestering” the carbon that came from the trees we just cut down, or do we want to leave the trees in the woods?

Builders who argue in favor of “sequestering” carbon by packing a building with lots of lumber argue that it's good to keep wood from rotting on the forest floor. After all, the wood frame of a well-built building can easily last 150 or 200 years.

But there is no simple summary or rule of thumb to guide builders on this issue. The New Carbon Architecture tries to settle this debate, noting that it’s possible to develop ways to analyze the CO2 emissions associated with lumber harvesting and processing. (Spoiler alert: a key variable is how the forest is managed.)

In most cases, the book concludes, it's better to leave a tree alone than it is to cut the tree down and to transport a portion of the tree to a sawmill: “If your main goal is to sequester carbon, one of the best things we can do with forests is to keep them around and let them grow old.”

Even if an engineer clearly understands that cutting down a healthy tree, turning it into lumber, and temporarily “sequestering” the lumber in a building isn’t good for the atmosphere, the carbon calculations associated with logging and sawmill operation are complex — so complex, in fact, that the book notes that “we urgently need to standardize the embodied carbon calculations and reporting methods.”

So “embodied carbon” is a tricky term. We’re not really concerned with how much carbon is embodied in our buildings. We are more concerned with CO2 releases associated with the building’s construction and operation. The book's authors understand these facts, of course; they describe embodied carbon as “the greenhouse gases emitted by extracting, producing, transporting, using, and waste-treating [building] materials.” But they never explain why the use of the word “embodied” makes sense.

Using embodied energy as a proxy for carbon calculations

In many ways, the definition of “embodied energy” is less muddy than the definition of “embodied carbon” — which is why many builders use an embodied energy calculation as a surrogate for an embodied carbon calculation. That’s an imperfect solution, of course, since some parts of the globe produce low-carbon electricity while others produce high-carbon electricity; but it’s a defensible approach in spite of its imperfections.

Regardless of which type of calculation you attempt, the math isn’t simple. There are many unknowns, and the calculations are all based partly on assumptions.

Traditional village homes don't emit much CO2

According to The New Carbon Architecture, “getting to zero embodied carbon can seem impossible. In fact it is impossible, let’s get real. Even a simple adobe hut has a few wires and windows (embodied carbon), and that wood-burning stove in the corner is effective and romantic but nonetheless emits operational carbon.”

While the tone of these sentences is dismissive, the sentences hint at an important point: In Third World countries, the rural poor have been building “zero embodied carbon” buildings for thousands of years. A mud hut with a straw roof does no harm to our planet’s atmosphere. When it comes to CO2 emissions associated with building construction, the most serious offenders all live in the wealthiest countries.

When my friends and I moved to rural Vermont in the 1970s, we were all building homes with very low levels of CO2 emissions. I cut spruce trees for my home’s joists just a few hundred feet from my building site. I gathered stones for my cellar walls with a wheelbarrow. The main energy used for these endeavors came from brown rice and black beans.

Will technology save us?

The New Carbon Architecture doesn’t advocate a return to the hippie building practices of the 1970s, however. Instead, it looks to a promising future ushered in by the latest technology, with anticipated breakthroughs from the fields of nanotechnology and 3-D printing.

Will these technologies save us? Perhaps. But the jury is still out.

As I noted earlier, The New Carbon Architecture has multiple authors. Some of these authors share a rosy vision of the future; others don’t. There’s a tension between these two visions.

The book’s main author, Bruce King, is optimistic about our future. He writes, “We can structure any architectural style with wood, we can insulate with straw and mushrooms, we can make concrete — better concrete — with clay, microbes, smoke, and a careful look in the rearview mirror and the microscope.” King imagines “a new ‘carbon positive’ architecture that builds with the carbon enticed from sky.”

King shares his enthusiasm for nanotechnology, robotics, and 3-D printing, all of which (he predicts) hold the promise of reducing CO2 emissions associated with construction. While King refers to research in these fields, he can’t point to a single example of nanotechnology, robotics, or 3-D printing that can be implemented by today’s green builders.

Building new buildings won’t solve the problem

A more sober assessment is provided in a section of the book authored by Larry Strain. Strain writes, “We can’t build our way out of this. … New, efficient, super-green, even net-zero buildings won’t reduce our emissions fast enough. In the first place, we don’t build enough — currently about six billion square feet per year — to make a difference. Operating six billion square feet of efficient, code-compliant buildings generates about 40 million tons of greenhouse gases, less than one percent of total U.S. emissions.”

Strain explains that from a climate change perspective, energy retrofit work makes more sense than new construction. He writes, “It used to be that you always started [an energy retrofit project] by making the building more efficient — more insulation, new high-performance windows, new efficient equipment and lighting — and after you made it as efficient as possible, then maybe you added renewables to power the building. This was mostly because photovoltaic panels cost a lot, so you wanted to buy as few as possible. With the cost of PVs dropping and the advent of new efficient and relatively inexpensive heat pumpHeating and cooling system in which specialized refrigerant fluid in a sealed system is alternately evaporated and condensed, changing its state from liquid to vapor by altering its pressure; this phase change allows heat to be transferred into or out of the house. See air-source heat pump and ground-source heat pump. technology, upgrading the equipment and adding PVs may be among the first things we do, not the last.”

Strain's realistic voice is at odds with the airy optimism that pervades the rest of the book. His chapter — which redeems an otherwise flabby book — is the most important chapter of The New Carbon Architecture.

No clear solutions on the horizon

After these two authors provide introductions to carbon accounting — with King presenting rosy predictions and Strain expressing skepticism about new construction — the book looks at concrete, straw bales, and adobe.

The usual pattern to these chapters goes like this: “We’re facing some serious problems, but scientists are working on solutions.”

The chapter on concrete notes that “cement production today amounts for about six percent of all anthropogenic global emissions [of carbon].”

The good news: a portion of the cement in concrete can be replaced by substitutes. The bad news: “Most common clinker substitutes [for cement] are wastes from industry such as fly ashFine particulates consisting primarily of silica, alumina, and iron that are collected from flue gases during coal combustion. Flyash is employed as a substitute for some of the portland cement used in the making of concrete, producing a denser, stronger, and slower-setting material while eliminating a portion of the energy-intensive cement required. More info, a by-product of coal power plants, or ground granulated blast furnace slag, obtained from virgin steel production. But both of these are in diminishing supply.”

The chapter discusses current research into new concrete recipes, but provides no obvious solution to the concrete problem. We’re told that “concrete can and must switch from climate villain to climate champion,” but today’s builders aren’t provided any specific advice on new approaches for foundations.

This is part of a pattern. The chapter on straw bale construction touts products (straw wall panels and straw blocks) that are still under development or unavailable in the U.S.

The book notes, “[S]traw bale walls provide high thermal performance … [T]he thermal resistance per inch is only about R 1.4-2.0 per inch, roughly half that of cotton batts or blown cellulose, but the bale itself is big. … [T]he wall assembly will be anywhere from 14 to 24 inches thick, making for a total package greatly exceeding any code stipulated thermal insulation requirements.” In fact, a 14-inch-thick straw bale wall has an R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of R-20 to R-28. An R-20 wall barely meets code in Zones 3 through 5, and is less than minimum code requirements in Zones 6, 7, and 8.

The chapter on clay (adobe) construction sings the praises of clay without providing any specific guidance to U.S. builders.

Moisture buffering

Another unsatisfying chapter describes the advantages of hygroscopic materials that provide hygric buffering to building assemblies. (For more on this topic, see Hygric Buffering and Hygric Redistribution.) The chapter notes, “Hygroscopic material can adsorb and desorb water vapor from the surrounding air, thus passively and beneficially regulating the indoor environment via moisture buffering.”

The chapter fails to explain how the use of hygroscopic materials can reduce builders’ CO2 emissions. Moreover, the chapter has several misleading passages, including this one: “A ‘breathing’ wall, roof, or floor is one that allows moisture vapor to pass through it, as process known as vapor diffusionMovement of water vapor through a material; water vapor can diffuse through even solid materials if the permeability is high enough. . … Breathing walls are less susceptible to material degradation because moisture vapor is less likely to be trapped as condensate within the building enclosure.” In fact, some wall types benefit from one or more layers that slow or prevent vapor diffusion.

One might think that in 2018, reviewers of books on green building would be spared the task of addressing the old “walls have to breathe” chestnut. But we’re not.

The book is padded

To fill out the book, the editors include miscellaneous chapters covering a grab-bag of topics. A chapter on indoor air quality claims that the quality of the interior air in energy-efficient homes is worse than in old, leaky homes. The book notes, “Drivers for improved energy efficiency have seen levels of airtightness improve so as to minimize uncontrolled heat losses and gains. However, the unintended consequence has been a degradation of indoor air quality with an increase in levels of VOCsVolatile organic compound. An organic compound that evaporates readily into the atmosphere; as defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then become involved in photochemical smog production. and extremes in relative humidity.”

I’ve never seen evidence that would support such a broad statement. In my experience, energy-efficient buildings are more likely to have a whole-house ventilation system than less efficient buildings; for this reason, most energy-efficient buildings have excellent indoor air quality.

Ann Edminster contributes a well-written article that argues in favor of maximum building heights. Edminster concludes that “A number of carbon and livability indicators suggest that cities would do well to limit building height to 10 or 12 stories.” While Edminster's logic is intriguing, the chapter is of little interest to the average residential builder.

Finally, the photo section is marred by several clumsy captions. A photo of mushroom-based insulation is captioned “Meet a fungi.” (Dude, the singular is fungus.) And a photo illustrating women in construction has a cringe-inducing label: “Girl power.”

Advice to builders

Although the book doesn't provide advice to builders, I will. If you care about embodied energy:

  • Don't build any new buildings.
  • If you must build a new building, use the shantytowns and favelas of the Third World as your model. The best way to build a new building is with materials scavenged from your local dump.
  • Remodeling an existing building is better for the planet than most types of new construction; however, remember that building materials purchased as part of a renovation project have embodied energy. A low-key project with as few new materials as possible is better than a deep-energy retrofit.
  • If you must build a new building, choose wood framing over steel framing or concrete.
  • The insulation material with the lowest embodied energy is cellulose. Because foam insulation has a high level of embodied energy, it is hard to justify the installation of very thick layers of foam insulation unless the rigid foam has been recovered from a building scheduled for demolition, or recovered from a roof that is being stripped. If you like rigid foam, buy recycled foam.
  • Green builders should remember that many dearly loved contraptions with a particularly long payback period — including solar hot water systems, earth tubes, and buried glycol loops used to preheat ventilation air — reveal themselves to be particularly egregious culprits in any analysis of the “front loading” problem.
  • Remember that for most construction companies, a significant part of the company's carbon emissions come from transportation — especially emissions associated with workers' daily commute to the job site. (For example, an analysis by the South Mountain Company concluded that 60% of the construction company’s CO2 emissions are associated with employees’ use of transportation fuel.) These emissions are hard to address, but carpooling is one way to reduce them.

Martin Holladay’s previous blog: “Finally, a Right-Sized Furnace.”


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  1. New Society Publishers

1.
Mar 9, 2018 12:15 PM ET

Foam vs. concrete
by Charlie Sullivan

Thanks for another good critique of a useful book that could have been better, and for providing pragmatic advice. I think it's worth elaborating the impact of foam insulation a bit. Given the central role of concrete in CO2 emissions from construction, I found it useful to use that as a reference point for comparison. Per cubic foot, the global warming potential of emissions from XPS foam is ten times higher than from concrete. On the other hand, from EPS or polyiso, it's five time lower than concrete.

In the spirit of simplifying the short list, I think it's reasonable to consider concrete and high GWP foam the only materials that are problems worth worrying about, and to remember that high GWP foam--XPS and most closed-cell spray foam--is an order of magnitude worse than concrete.


2.
Mar 9, 2018 1:34 PM ET

Response to Charlie Sullivan
by Martin Holladay

Charlie,
Thanks for the quantification of the climate impact of XPS and most brands of closed-cell spray foam, and for the helpful advice.


3.
Mar 9, 2018 8:53 PM ET

Charlie
by Malcolm Taylor

I second Martin's thanks. Both Martin and your lists reducing a complex topic down to a few prescriptive axioms are very helpful.


4.
Mar 10, 2018 2:04 PM ET

Edited Mar 10, 2018 2:06 PM ET.

My thoughts on this week's blog
by Armando Cobo

These types of books and articles, usually talk about a smaller sector of the (residential) construction industry, as if we all live in rural America or New England. We must recognize that the greatest majority of homes built in the US are built by production builders in large markets, up to ±70%. See attached NAHB charts.
Designing and building high-performing and zero energy (ready) homes for most of my professional life in several states, and mostly custom or small production, I can tell you that some of the information and advice in this blog is out of touch with OUR, and most production builder reality, and the reality of the mid/major cities combined.
• “Don’t build new buildings” – In Dallas (DFW), houses built 20-100 years ago are very expensive to retrofit to high-performing levels, and most people do not have unlimited budgets. Most retrofit money is spent on the HGTV “lipstick on a pig” philosophy. There is no way to “harvest” our own wood, or make our own adobe bricks and straw bales, so we have to go with the most economically viable solutions for large markets.
• “Remodeling an existing building is better for the planet than most types of new construction” – During 2017 in DFW, the top house market in the country, there were 98k homes sold… 2/3 were existing and 1/3 new. There are not enough built houses to remodel to satisfy the demand of all new folks moving to NTX, and the ones that were remodeled, see point above.
• “…a significant part of the company's carbon emissions come from transportation” Really? Solutions anyone? I don’t see mass transportation going to must suburbs were production builders build, and subcontractor’s companies come from all over the metro area.

National Market Shares.jpg Custom Market Share.jpg Regional Sale Type.jpg


5.
Mar 10, 2018 3:54 PM ET

Edited Mar 10, 2018 5:27 PM ET.

Response to Armando Cobo
by Martin Holladay

Armando,
I gave advice. Advice is cheap. Do I expect any readers to take my advice? No.

So what's going to happen?

The U.S. home building industry will continue conducting business as usual. New homes will be built, and lots of CO2 will be released into the atmosphere as a result of builders' actions. Workers will drive their pickup trucks to job sites in the suburbs to build these homes.

Some GBA readers will build homes with extra insulation and triple glazing -- above-code features that (when manufactured and delivered to the job site) will emit even more CO2 into the atmosphere than materials destined for homes with code-minimum insulation and double glazing.

U.S. home builders are unlikely to leave the well-trodden path of business as usual. Of course, builders aren't the biggest climate culprits. But it's fair to say that Americans and Canadians -- whether they work as builders or architects or doctors or schoolteachers or firefighters -- emit far more carbon per person than Somalis or Ugandans.

CO2 emissions in the U.S. and across the globe will continue to increase, and average global temperatures will continue to rise. By 2035 or 2040, our actions will have caused an irreversible and catastrophic change in our climate that will lead to rapid melting of polar ice caps and rising sea levels.

Species will continue to go extinct at a rapid rate -- a mass extinction event that will remain in the fossil record for millennia.

Millions of climate refugees will leave their homes, in desperate search of a safe haven.

It's very hard to see a likely path to avoid these predictions.


6.
Mar 11, 2018 8:14 AM ET

One more point, Armando
by Martin Holladay

Armando,
You wrote, “Most retrofit money is spent on the HGTV 'lipstick on a pig' philosophy. There is no way to 'harvest' our own wood, or make our own adobe bricks and straw bales.”

I agree completely. Some of the authors of the book I reviewed (The New Carbon Architecture) implied that adobe and straw are part of the solution to the climate change crisis, and I disagree. As I wrote in my review, "Today’s builders aren’t provided any specific advice on new approaches for foundations. This is part of a pattern. The chapter on straw bale construction touts products (straw wall panels and straw blocks) that are still under development or unavailable in the U.S. ... The chapter on clay (adobe) construction sings the praises of clay without providing any specific guidance to U.S. builders."

That's why my predictions are so pessimistic, and why my unrealistic advice is likely to fall on deaf ears.


7.
Mar 11, 2018 8:58 AM ET

We sit At The Same Table
by Doug McEvers

Martin,

You have said what needs to be said, we are headed for a train wreck. Even drastic actions today will most likely be ineffective in curbing runaway climate change. GBA has provided a forum for thoughtful discussion on building greener with our limited fossil energy in mind. Let this much needed discussion continue.


8.
Mar 11, 2018 10:10 AM ET

> It's very hard to see a
by Jon R

> It's very hard to see a likely path to avoid these predictions.

About 50 years of mandatory birth control? Oh, you said likely.

Slightly more seriously, I suggest fixing the federal budget deficit with carbon taxes.


9.
Mar 12, 2018 7:08 AM ET

Response to Jon R
by Martin Holladay

Jon,
As I have said many times, the imposition of steep carbon taxes would be a logical response by government leaders to our current climate crisis. Although policy experts and climate scientists have made the suggestion for decades, U.S. leaders have so far failed to implement this suggestion.


10.
Mar 12, 2018 8:40 AM ET

"In fact, a 14-inch-thick
by Dana Dorsett

"In fact, a 14-inch-thick straw bale wall has an R-value of R-20 to R-28. An R-20 wall barely meets code in Zones 3 through 5, and is less than minimum code requirements in Zones 6, 7, and 8."

It's a mistake to use center-cavity prescriptive R-values for framed buildings when assessing the code-compliance or thermal performance of other types of construction. In fact R20 straw bale construction can meet code minimum requirements everywhere in the US.

Straw bale construction has nowhere near the thermal bridging of framed buildings, since they not stacked between 2x framing timber. They comparable to (but usually less than) the thermal bridging of a Larson Truss, with a whole-wall R close to the center-cavity R value.

Code min in zones 6 through 8 is a maximum of U0.045, or R22.2 "whole wall". If the hay bale itself Is R20, the air films plus interior & exterior finish materials can bring it over that mark. If the hay bale itself is R24 (mid-range of the estimate) it's a no-brainer, unless the designer goes WAY out of the way to subvert thermal performance with the structural elements.

But thickness notwithstanding, those aren't "super insulated" walls, except relative to code requirements of zones 1& 2, and only ~1.5x code performance for zones 3 through 5.


11.
Mar 12, 2018 9:42 AM ET

Response to Dana Dorsett
by Martin Holladay

Dana,
I agree with your analysis. I was simply referring to the minimum R-value requirements from the prescriptive table. You're right, however, that other code compliance paths make more sense for straw bale builders, since the other compliance paths provide more credit for a straw bale wall.


12.
Mar 12, 2018 1:52 PM ET

Carbon Sequestration
by Robert Lepage

“If your main goal is to sequester carbon, one of the best things we can do with forests is to keep them around and let them grow old.”

This doesn't seem aligned with the evidence and information provided by the IPCC. Dr. Werner Kurz of Canada's Pacific Forestry Centre (also a contributor to the IPCC) has done extensive research on forest carbon budgets. The answer is not simple, but generally, it is better to remove a tree from a forest, replace it, and convert it into a long-lived product than to leave it in the forest.

This is one of his presentations to the Pacific Institute for Climate Solutions:


13.
Mar 12, 2018 2:34 PM ET

Edited Mar 12, 2018 4:18 PM ET.

Response to Robert Lepage
by Martin Holladay

Robert,
My review noted, “Is this temporary sequestration of carbon good or bad for the planet? Suffice it to say that the answer is, 'it depends' — and the calculation isn’t simple.”

I urge anyone interested in diving deeper into this issue to buy the book under review (The New Carbon Architecture). Remember that the authors of The New Carbon Architecture are focused on climate solutions that reduce CO2 releases during the next 10 or 15 years, and specifically aim to avoid "solutions" that involve large front-loaded releases of CO2 that are made up over the next 100 years by a delayed balancing factor — for example, long-term forest regeneration that takes decades to occur.

Here is a longer quote from The New Carbon Architecture:

"...[W]hen it comes to carbon, not all wood is equal: wood may be good, but wood from good forestry is much better. This is true not only when it comes to combating global warming but for myriad other reasons as well.

"In our search for solutions to the climate crisis, we tend to miss the forest for the timber. If your main goal is to sequester carbon, one of the best things we can do with forests is to keep them around and let them grow old. Older forests generally capture and store far more carbon over time than do younger forests. And the oldest forests store the most: what remains of the Pacific coast's original ancient forests are among the greatest carbon sinks on the planet...

"Much is made of the fact that wood stores carbon for the length of its life in a building, ignoring the fact the carbon embodied in wood products accounts for only a fraction of the overall carbon stored in the forest they come from — as little as 18 percent by one estimate. Of the remainder, large amounts may be released to the atmosphere when logging slash rots and soils are exposed by logging. For decades after they occur, clearcuts emit more carbon than regeneration absorbs in spite of the rapid growth rate of young trees. This is because decomposer microbes in the soil work more quickly after a stand is logged, releasing CO2 as they decompose branches, roots, and other organic matter.

"...[C]onventional LCA [life cycle assessment] does not currently address harm that logging may cause to the integrity and diversity of forest ecosystems, to water quality, or to threatened and endangered species.

"Most experts contend that LCA's omissions are not due to any deliberate attempt to deceive, but rather because LCA is the wrong tool for the job — it doesn't have the capacity to reliably measure forest carbon or ecological impacts, much less regulate them."


14.
Mar 13, 2018 1:39 PM ET

Response to Martin
by Robert Lepage

Hi Martin,

The issue follows:
"If your main goal is to sequester carbon, one of the best things we can do with forests is to keep them around and let them grow old."

In isolation, this is true, but as you rightly indicated, reality is much more complicated rendering this statement unfortunately false. Dr. Kurz' work demonstrates the shortcomings of many of the points indicated in your quoted section of The New Carbon Architecture, using peer reviewed and scientific research. The video linked above provides a good summary of the concept.

A few snippets:
Climate change mitigation strategies in the forest sector: biophysical impacts and economic implications in British Columbia, Canada. 2017. Xu, Z.; Smyth, C.E.; Lemprière, T.C.; Rampley, G.J.; Kurz, W. A. Mitig Adapt Strateg Glob Change, pp 1–34

Modelling forest carbon stock changes as affected by harvest and natural disturbances. II. EU‑level analysis. 2016. Pilli, R.; Grassi, G.; Kurz, W.A.; Moris, J.V.; Vinas, R.A. Carbon Balance Manage 11:20.

Estimating product and energy substitution benefits in national-scale mitigation analyses for Canada. 2016. Smyth, C.; Rampley, G.; Lemprière, T.C.; Schwab, O.; Kurz. W.A. GCB Bioenergy

Estimating carbon dynamics in forest carbon pools under IPCC standards in South Korea using CBM-CFS3. 2016. Kim, M.; Lee, W.; Kurz, W.; Kwak, D.; Morken, S.; Smyth, C.; Ryu, D. iForest - Biogeosciences and Forest.

Constraining the organic matter decay parameters in the CBM-CFS3 using Canadian National Forest Inventory Data and a Bayesian inversion technique. 2017. Hararuk, O.; Shaw, C.; Kurz, W.A. Ecological Modelling 364(2017):1-12.

Climate change mitigation potential of local use of harvest residues for bioenergy in Canada. 2017. Smyth, C., Kurz, W. A., Rampley, G., Lemprière, T.C., Schwab, O. GCB Bioenergy, 9: 817–832.

Best,
Rob


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