It sounds like a pun to refer to the Global Warming issue as a hot topic, but with the U.S. Congress set to consider legislation on Climate Change in 2009, it is certainly a relevant subject for Regenerate. It is relevant because of the profound and positive impact that wood, nature’s most useful carbon storage resource, can and does have in every equation concerning the human impact of building and home furnishing products on our planet. But attention to the topic of global warming brings politics. Thus, the wood story could turn out to be a good news/ bad news story. Here’s to our hope that good carbon science doesn’t lose out to politically driven science.
WOOD IS GOOD, REALLY GOOD
The primary reason wood ends up with such a positive result when the scientists tally up all the factors in their carbon equations is energy; more specifically, ‘embodied energy’. Trees use the ultimate renewable source of energy, solar energy, to pull carbon out of the atmosphere and create wood. Approximately half the weight of wood comes from carbon. Wood products manufacturing also expends much less energy to turn that natural resource into lumber, composites and even kitchen cabinets.
Additionally, wood products manufacturing uses a huge proportion of ‘carbon neutral’ biomass energy in their manufacturing operations, between 50-67%. Over 60% of the biomass fuel consumed in the U.S. is in fact used to create wood products. (Murray et al. 2006). Comparisons are almost pointless since no other commodity industry comes close, when it comes to the use of biomass fuels.
In its pointed summary of the facts related to wood, the not-for-profit Dovetail Partners’* Carbon Science vs. Carbon Politics report, (Bowyer, et.al., 2008) gets quickly to how much better wood is than some of the competing materials. “High energy efficiency and low fossil fuel consumption, combined with the fact that wood is one-half carbon by weight, means that wood and the products made from wood tend to be not only carbon neutral, but carbon negative. That is to say, that even when carbon emitted in all the steps of processing is considered, the net result is carbon storage rather than emission of carbon; this is not the case for any other construction material” Figure 1 is a bar chart of some selected comparison materials.
The Dovetail Partners report goes into much greater detail in this area. It is recommended reading. So the science says “wood is good, really good” when it comes to carbon storage and carbon use. Unfortunately, the politics of carbon (carbon treaties, carbon trading, etc.) paint a much murkier picture.
POLITICS OF CARBON
As the Dovetail Report notes, “In developing incentives and protocols to reduce carbon emissions and increase carbon sequestration, one glaring omission stands out. Storage of carbon within wood products has thus far been ignored by policy analysts, as has the low energy intensity (and even lower fossil fuel intensity) of wood products in general. The omission is significant since in the United States alone carbon stored within wood products is over one-third that being sequestered annually within the nation’s forests.”
Because the embodied energy in wood products is low compared to equivalent products made of competing materials, energy is saved and emissions avoided each time wood is substituted for these other materials when building homes or stocking them with furnishings. Dovetail continues, “As long as substitutions are appropriate (i.e. result in similar durability over time), and the management of forests from which wood is harvested is sustainable, there is clear environmental advantage to use of wood wherever possible.”
Currently, forest-related strategies available for earning carbon credits toward compliance with the Kyoto protocol are limited to the establishment of forests on areas previously lacking forest cover, or on lands degraded by agriculture or mining. Despite a large body of research on wood’s carbon storage capability, there is no recognition to date by climate negotiators of the potential for storing carbon in wood products or of avoiding carbon emissions through product substitution. The current assumption regarding the fate of harvested wood is that once a tree is harvested, all of its carbon is released and that the net stock of carbon in long-lived wood products is unchanging.
Fortunately, there is now broad recognition that the existing assumptions about wood are faulty. There are initiatives underway that would bring changes and allow for carbon storage within carbon accounting schemes. Although there appears to be tentative discussion about the carbon storage issue under the United Nations Framework Convention on Climate Change (UNFCC), the outcome is far from certain.
It is unlikely that a decision on the carbon storage issue will be based on science alone. Dovetail goes on to say, “The data on carbon storage in wood products and their low-energy intensity is increasingly well documented and readily available. The time is right and strong opportunities exist for carbon protocols and markets for carbon credits to recognize the carbon storage benefits of wood products.”
“High energy efficiency and low fossil fuel consumption, combined with the fact that wood is one half carbon by weight, means that wood and the products made from wood tend to be not only carbon neutral, but carbon negative.”
Mankind continues to search for ways to capture the power of the sun. It turns out that one of our most familiar materials – wood – is produced almost entirely from solar energy. Wood products store carbon, in massive amounts. The manufacture of these products is not only highly energy efficient, but the resultant emission of carbon dioxide is lower, in the extreme, compared to other materials. If society is serious about reducing carbon dioxide, recognition of these differences is important in the development of green building and green purchasing programs. As governments adopt green principles into law and regulation, they need to remember that one part of the solution is growing on trees.
* The Dovetail Partners is a 501(c)(3) nonprofit corporation that provides information about the impacts and trade-offs of environmental decisions, including consumption choices, land use, and policy alternatives. For more information, visit www.dovetailinc.org.
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