OR-Dept-Environmental-Quality / wic-base

Fundamental data and documentation for the Waste Impact Calculator (WIC) framework. See https://or-dept-environmental-quality.github.io/wic/ for an overview of WIC project.
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consider the diff between prevention and reuse in wood #65

Open DEQmbrown2 opened 3 years ago

DEQmbrown2 commented 3 years ago

Hey @DEQpcanepa and @DEQjpalmeri , thanks for the discussion/clarifications today about the GWP impact results for wood, especially the contrast between the reuse credit and the production impact. I know we all need a break from WIC, but here is an issue to consider in whatever month or year ahead we return to WIC to improve it.

As you recall, for biogenic GWP categories, the magnitude of the wood reuse credit is actually larger than the magnitude of the production impact. This is internally consistent, but if interpreted naively, would suggest something bizarre: that we should cut down all our forests and continually reuse the resulting wood.

I am writing this note because I think I get the fundamental reason for it, and I wanted to remember this insight (???). Also to check my thinking with Peter. Basically, my idea is this: WIC is an LCA of waste which includes production impacts. The whole premise of the calculations is that if there is no waste, then nothing was produced, and if nothing is produced, there is zero impact. This makes sense for almost anything based on extraction of static earthly resources (fossil fuels, mineral ores, etc). It also makes sense for very short-lived biological products, such as annual crops. However forest products are fundamentally different, because forests are not static. If nothing is extracted, impacts do occur... usually "good" impacts like carbon sequestration.

This special quality means it is very hard to model prevention of wood use inside a general LCA model of waste materials.

So maybe it's not a problem we need to fix -- but just something we want to help our users understand?

Feel free to respond to this at any point in the future -- today or six months from now. -martin