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Researchers Urge Revamp of Methodologies for Carbon Footprint Calculations
16 August 2008
Researchers at Carnegie Mellon University (CMU) are urging companies to adopt new, broader and more consistent methods for calculating their carbon footprints.
Accepted frameworks for tracking industry carbon emissions rely on tiers of increasingly broad scope. Tier one generally includes emissions by the company’s own activities, such as burning gasoline in fleet vehicles or natural gas in its facilities. The second tier boundary expands to include emissions from electricity and steam purchased by the company. Tier three includes all other emissions, including the entire supply chain of goods and services. In practice, most companies reporting their greenhouse gas emissions opt to use only the tier one or the tier two boundary.
By far, most companies are pursuing very limited footprints—toe prints really—instead of comprehensive ones.
—H. Scott Matthews, CMU associate professor of civil and environmental engineering and engineering and public policy
To put the implications of this boundary decision into context, CMU researchers Matthews, Chris T. Hendrickson and Christopher L. Weber developed a new method that estimates the amount of greenhouse gas emissions across all tiers of the entire supply chain for all industries.
We argue that the footprints should be useful in pursuing more effective climate change policies. However, the information contained in a carbon footprint varies depending on how it was calculated and how much responsibility the entity being “footprinted” is willing to take on. There is an inherent trade-off between comprehensiveness (i.e., the percentage of total world GHG emissions included in a system) and participation (i.e., the percentage of businesses or consumers taking part in the system). Because consumers can influence the carbon footprints of goods and services through their purchase decisions, a broad estimation of carbon footprints including supply chain effects is appropriate. Similarly, as a corporation can influence its suppliers, a broader estimation can similarly motivate more effective corporate climate change policies.
However, there is a limit to the extent to which final consumers and even intermediate businesses can affect emissions occurring far up the supply chain. Thus, a balance must be made, and consistent, comprehensive rules must be developed to decide the proper extent of inclusion for supply chain GHG emissions.
—Matthews et al. (2008)
In a study published in the 15 August edition of the journal Environmental Science & Technology, the authors utilized a specific implementation of an input-output model for the US economy, the 1997 Economic Input-Output Life Cycle Assessment (EIO-LCA) method developed at Carnegie Mellon University, with the full model freely available online at www.eiolca.net.
They report that two-thirds of US industries would overlook more than 75% of their total greenhouse gas emissions if they continue to use the same tier one or tier two reporting boundaries. The average industry has only 14% of its total greenhouse gas emissions in tier one and 12% in tier two for a total of 26%.
Nearly two-thirds of all economic sectors providing goods and services (323 of the 491 industries) would have less than 25% of their total carbon footprint represented by Tiers 1 and 2. The 10% of sectors that would have most of their footprint (80+%) represented by Tiers 1 and 2 are well-known sources such as power generation, cement manufacturing, and the transportation sectors (air, truck, rail, and water). Sectors with large and known carbon footprints are already aware of their emissions (and more importantly, so are government agencies such as the US EPA and the Department of Energy). Other sectors of the economy are just beginning to think about their footprints.
Decision-makers in those sectors would not be well-served by using the broadly promoted protocols to estimate their total carbon emissions, because a majority of their emissions occur farther down the supply chain than Tier 1 and Tier 2 examine. Further, these decision-makers may be lulled by existing protocols into assumptions that carbon legislation will mean little to them if they are not aware of the effect supply chain emissions will have on their input prices.
—Matthews et al. (2008)
The study examines two industries—book publishing and power generation—as case studies.
Book publishers have low Tier 1 and Tier 2 emissions relative to their total footprint, they found, representing only 6% of the total. Publishers also represent a sector, the authors point out, where a large proportion of emissions occur from final delivery, through either personal vehicle trips or package delivery services. “Although current standards would only include delivery emissions if trucks were owned by the publishers, consumers and some firms may wish (or be required) to take responsibility for these emissions.”.
Power generation, by contrast, is a well-known source of GHG emissions, contributing 37% annually. The majority of that is from burning fossil fuels, putting 92% of their emissions in Tier 1. “Nevertheless, the delivery of fuels to power plants still represents a significant source of GHG emissions (such as rail deliveries of coal and natural gas pipelines). These emissions would probably fall outside of traditional Tier 1 and Tier 2 footprint approaches.”
The authors propose modifying the tier structure by extending Tier 3 and adding a fourth to support a more comprehensive approach for footprint estimation. Their tiers are:
Tier 1: No change: Emissions directly from company operations.
Tier 2: No change: Emissions from energy inputs to company operations.
Tier 3: Change to entire supply chain (cradle-to-gate) emissions for a good or service.
Tier 4: Include total life-cycle emissions for production (Tier 3) plus delivery, use, and end-of-life.
Resources
H. Scott Matthews, Chris T. Hendrickson, and Christopher L. Weber (2008) The Importance of Carbon Footprint Estimation Boundaries. Environ. Sci. Technol., 42 (16), 5839–5842 doi: 10.1021/es703112w
August 16, 2008 in Climate Change, Market Background, Sustainability | Permalink | Comments (8) | TrackBack (0)
Comments
Posted by: tom deplume | August 16, 2008 at 11:19 AM
Tom mentions a problem with over counting.
Conglomerates follow specific accounting rules to cancel transactions between subsidiaries. Otherwise you can keep selling to yourself and grow to any size. No overall profits of course, but a given subsidiary can look good.
Enron didn't quite dare do that but there are other methods.
If a given company wants to analyze all four tiers for internal purposes that might be useful. But generally the highest number and worst possible interpretation will be leaked to the media. And then the company will be accused of lying and deception if they ever say anything else.
The higher the Tier # the less definite it is.
Notice this rather moderate statement from the report:
"However, there is a limit to the extent to which final consumers and even intermediate businesses can affect emissions occurring far up the supply chain. Thus, a balance must be made, and consistent, comprehensive rules must be developed to decide the proper extent of inclusion for supply chain GHG emissions."
Who believes the popular media will report that part?
Posted by: K | August 16, 2008 at 03:34 PM
There may be considerable evidence that there is a warming of the earth due to the human release of Carbon Dioxide. While there are many possible results of this increased temperature, there is no definite conclusion possible that this result would not be favorable to the earth's ecosystem. Most of the results proposed will damage human populations, but this is not necessarily a detriment to the overall set of the earths biosystems. In fact the massive reduction of homosapien inhabitants of the earth would allow the restoration of other inhabitants of most areas.
When the numbers of homosapiens were quite small or even non-existant, the earth had both much cooler and much hotter climates at times. This means that homosapiens are not needed for all climate changes or that any climate change is unnatural. Homsapiens are after all a product of the same forces that brought into existence the Irish Elk and great blue whales.
The companies and countries that produce and sell hydocarbon fuels could be held accountable for carbon releases into the atmosphere with similar and no less valid logic than that those who burn them are.
Nuclear reactors, including the always to remain fictional earth bound fusion reactors, are the lowest cost source of energy for homes and industry. The collection costs of wind and solar energy put them in a more expensive category. Neither source is renewable because once a site is used it cannot be used by additional equipment.
Every life form that exists or ever existed must ingest almost the exact same amount of radio-active potassium as its remote ancestors did in order to live. All creatures(great and small) have always been naturally radio-active and exposed to even more natural radio-activity from earth and space.
The immeasurable additional radio-active exposure from nuclear power plants is of no real concern; Even natural gas fired power plants release more radio-activity into the air than do nuclear power plants, and coal fired plants are much worse. China has begun extracting uranium from coal ash at one of its power plants.
Converting to nuclear power will reduce the radio-activity put into the air not only the CO2. A piece of nuclear fuel that weighs as much as a five cent coin produces as much energy as a thousand pounds of coal. And some reactor systems, already in operation, can get ten times as much. According to Craven's sources, if a persons entire life time energy use were derived from nuclear fission, all of the nuclear waste products generated would fill a Coke(TM) can. The average person in the US uses twenty pounds of coal a day and produces about two pounds of ash and 50 pounds of CO2.
Used nuclear fuel rods, now in storage, could produce all the electrical energy needed by the US for a century by known and operating processes. This can be improved by proposed processes. Or the entire collection from a reactor can be thrown down a partially filled deep oil well and then followed with more than a thousand feet of clay and concrete. This is far more than adequate to protect any homosapien. Airplanes are statistically a million times more dangerous.
Another statistically safe means of disposing of fuel rods or even plutonium is to take a square mile of a clay bed and then mix a solution of dissolved fuel rods with a sufficient amount of clay so that the natural radio-activity is only increased by one tenth and then put the clay back. No one will ever be measurably harmed by even bathing in the clay and none can extract any dangerous amounts of the added materials.
Such a solution of the fuel rods could also be wasted by mixing it uniformly with any cubic mile of ocean water.
The fact that every creature must have billions of atoms of radiactive potassium incorporated into itself in order to live and must tolerate the exploding of thousands of these atoms every second and, in addition, must tolerate the other natural radio-activity of earth and space, must logically lead to the conclusion that radio-activity can be lived with. Any one that believes that nuclear power should be forbbiden because of the radio-activity, must logically forbid people to live in Denver rather than San Diego or forbid airline travel. If nuclear power replaced coal power it would reduce radio-active exposure, but not by an amount that could be measured on any individual.
There is no logical reason to protect people from the radio-activity of the used, but not spent, fuel with any higher degree of care than they are from the natural radiation of the earth and universe or food. ..HG..
Posted by: Henry Gibson | August 16, 2008 at 07:49 PM
The Triple Lindy
http://www.youtube.com/watch?v=2FUxUiMyt70
FTW
Posted by: Joseph | August 16, 2008 at 10:39 PM
@ Henry Gibson
In the interests of keeping this blog a productive and inspiring area for discussion, let's try to keep content to the topic at hand. Soap-boxing, though fun for your ego, is not enjoyable for others.
Posted by: Jer | August 17, 2008 at 06:21 AM
Jer- well said.
Posted by: jc777 | August 17, 2008 at 12:08 PM
Here is a link to Carnegie Mellon's online resource that provides the details:
http://www.eiolca.net/about.html
Posted by: Mark | August 18, 2008 at 11:58 AM
What about EHVs then?
Their second tier footprint can be huge.
And fuel cells use hydrogen, but extracting H2 takes vast amount of energy too.
Posted by: Tun | August 26, 2008 at 08:46 AM
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It looks like this approach could result in some emissions being counted 2 or 3 times. Company A buys supplies from company B. The carbon in what they buy is first counted by company B as a tier 1 and again counted by company A as a tier 2. Adding them up results in more than what is actually emitted. This could result in much more being accounted than the economy wide total. It is similar to how the GDP of an area can be many times the amount of actual money in existence.