A report by the Manomet Center for Conservation Sciences, commissioned by the Massachusetts state government, was released finding that biomass emissions for energy have real climate impacts. The report contains lots of good insights and shows quite definitively that biomass emissions must be included in our estimates of the climate impact of products, industries or activities. It is an important report and an important advance in the discussion.
That said, the report makes two assumptions that tend to underestimate the impact of biomass emissions and thus under-sell the need for policy changes to take the real impacts of biomass emissions fully into account.
The first is the idea of 'replacement' as the goal of policy. The second is the idea that the comparison of biomass should be limited to fossil fuel emissions. Now, Manomet may have been working strictly under the terms of reference given to them by the Massachusetts state government. But the deficiencies should be pointed out nonetheless.
Replacement. The idea that the use of biomass starts to yield benefits once the forest or ecosystem 'replaces' the carbon once released is the wrong baseline. The forest in question, if left unharvested and not used as biomass, would not be static. It would grow and absorb additional carbon in most cases. Thus, in the period of 'replacement, the forest might go from 50 tons of carbon per unit area (let's say) to more: 60, 75, or some other amount. So, the real impact is greater than the measurement against 'replacement.' Replacement may be a useful measurement tool, like measuring a half-life of radioactivity, but it is not the full impact. If we leave more forests intact without harvest for longer periods, we will tend to have that much carbon and more. That last option is the best option for the climate and is where we should drive policy. (Aside: this policy can also be beneficial to land-owners, since we might enact policies that encourage them to keep their forests intact for longer, such as tax breaks for those doing so, something like the Conservation Reserve Program that is so successful.)
Comparisons of impact. The report compares emissions from biomass to emissions from fossil fuels. It's a useful exercise. But it's not our only option. And we need to make those options very clear so we can decide collectively how to get at the problem in the best way. Our choices are not limited to biomass or fossil fuels. Conservation of energy measures and investing in wind, water and solar options are also on the table, though under-invested in.
Here is what the report presents:
|Fossil Fuel Technology||Carbon Debt Payoff (yr)|
|Oil (£6), Thermal/CHP||5|
But a more robust analysis of options might look something more like this:
|Alternative||Carbon Debt Payoff (yr)|
|Oil (#6), Thermal/CHP||5|
|Wind, Water, Solar||?, >150, >200 ?|
|Source Reduction||180, >240 ? ">?, >180, >240 ?|
As I wrote earlier, these are already underestimates, but leaving out the fact that our best policy alternatives are not referenced is a weakness in the report.
Sincere congratulations to Manomet for advancing the debate, but let's not forget what our best options are: keeping more forests storing more carbon across the landscape for longer periods and swapping out fossil fuels as rapidly as possible for conservation, wind, water and solar.