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Part 5 – Does Reforestation Contribute to Global Warming? – A second look at the Livermore Study

By: Kevin Peterson, CEO
Eco Preservation Society

( We would like to invite all of those interested in this subject to join our ongoing discussion at Treehugger.com . )

In 2005 Lawrence Livermore Laboratory and Carnegie Institution produced a study that sent ripples through the reforestation community and has influenced many of those interested in carbon offsets and carbon neutral programs. Many have embraced the findings from this study and many have concluded that reforestation has limited value in efforts to decelerate the warming of the planet. Dr. Caldeira of the Carnegie Institution referred to tree planting as a “feel good solution”. We feel strongly to the contrary, we feel that a long-term effort at sequestering carbon is vital and that reforestation is the only means presently at our disposal.

This study has been frequently referenced under splashy headlines by bloggers all over the Internet. Many, if not most of these bloggers are within the environmental movement. We feel that they have been led astray with faulty conclutions.

To date there has been little, if any, serious scrutiny of the findings of this study. Indeed many have extrapolated conclusions that are well beyond the scope of what was actually measured. The purpose of this article is to take a closer look at the Lawrence Livermore Study and put its findings into a more meaningful context.

First, by the study’s author’s own admission, the Lawrence Livermore study was predicated on an unrealistic scenario. The modeling was based on the single metric of replacing 100% of ALL grasslands and 100% of ALL croplands with evergreen trees! The modeling techniques did not take into account geological variations, topographical variations, altitude, regional weather patterns or microclimates. What the Lawrence Livermore study accomplishes is nothing more than a broad approximation based on a single variable, with that single variable being latitude.

Second, there is a significant time variable when measuring the “possible Albedo Effect” identified in the report. According to the study, the “possible Albedo Effect” does not come into play until 80 years following reforestation. What the Lawrence Livermore study assumes is that the there is no harvesting of the trees in its conclusions. If reforestation efforts north of 50 degrees are followed with a harvest of the trees prior to year 80 in the project there is no Albedo effect. Within this context a strong argument might be made that harvesting trees for wood products may be a effective way of sequestering carbon.

Third, there is no Albedo Effect with non-coniferous trees that loose their leaves during snowy periods.

Finally, it seems to me that the study assumes that there is no snow covering the trees. I have flown over snow-covered forests many times. While I might not be a scientist Lawrence Livermore, I can attest that at high altitude there is just not that much variation in the reflectivity on a snow covered typography. How much Albedo Effect can there really be if the trees are covered with snow? My understanding of the study is that it is comparing the reflectivity of green trees vs. white snow. Is this realistic of real world condition? I tend to think not.

Conclusion: The Possible Albedo Effect discussed the Livermore Study is limited to 80-year-old stands of evergreen trees north of 50 degrees latitude. Even within this limited conclusion, the results are not proven. It should be noted that this limited finding has not been confirmed by independent research. Nor does the study account for variations in Possible Albedo Effect based on regional weather patterns, geological variations or for conditions when trees are covered with snow. Vast regions of the Canadian plains have never been forested and do not have a climate to support a forest. Why should those areas be included in the measurements of this study? This study took into account only one factor, latitude.

Many of those that have embraced this study would suggest that all of our efforts should be focused solely on reducing our carbon emissions. Certainly technologies that allow us to achieve these reductions are of critical important to our future. However, from our view this is not an either/or proposition when comparing Emission Reductions to Carbon Sequestration, both are vitally important. It is of critical importance that we both reduce our emissions and reduce the amount of additioal CO2 that we have added (and will continue to add for the next 20 or 30 years) to the atmosphere.

By: Kevin Peterson, CEO
Eco Preservation Society

Part 1 – Does Reforestation Contribute to Global Warming?
Part 2 – Reforestation, Aldedo and Lawrence Livermore Study
Part 3 – Rain Forests: The World’s Air Conditioner
Part 4 – Planting Trees in Cities
Part 5 – Does Reforestation Contribute to Global Warming? – A second look at the Livermore Study
Part 6 – Getting Our Priorities Straight – Common Sense Solutions to Climate Change

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2 Responses

  1. carolynallen says:

    Thank you for putting emissions reduction and carbon sequestration into perspective. Trees offer such a wide variety of benefits..not only for carbon sequestration, but runoff control, cooling urban heat islands, wood for products and building and paper — as well as habitat for wildlife, replenishing soil with nutrients …and livability benefits. Yeah for Trees! Carolyn

  2. ruhart says:

    At last, a coherent rebuttal of the Caldiera/Bala work. Briliant. A few additional thoughts. The zeal with which certain sections of the media and the ‘green community’ seized on this research and used it to attack the idea of forestry based offsets was bizarre wasn’t it? It is so self-evident that we should be finding ways to take advantage of the enormous potential of forests to withdraw CO2 from the atmosphere. Maybe as foresters in Northern latitudes we need to take more account of the albedo of our trees but these guys have thrown out our biggest natural ally in the fight against climate change on the back of simplistic, partisan research by people who seem to know little about trees.

    As you point out, the described warming only occurs once the dense foliage of a close canopy is established. Anybody who knows anything about offset forestry understands that it is at precisely this point that the trees need to be harvested and their absorbed carbon conserved as timber. There is simply no warming if the forest is managed in this way. If anybody has a counter argument to this, could we hear it?

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