Dual debuts in this critical investigation of cross-laminated timber — multi-ton panels built from lumber that are the hottest material in “sustainable” building. It’s my debut work for Seattle-based nonprofit reporting outfit InvestigateWest as well as my first article in MIT-based science magazine Undark, which co-published the finished product.
Spoiler alert: CLT producers promote their building material as a climate solution because their giant wood panels can replace energy-intensive concrete and steel construction. My investigation reveals that the carbon accounting behind their claim is oversimplified, and too many journalists give short shrift to concerns from sustainable materials experts.
Take one study of CLT’s carbon footprint that VOX’s high-profile sustainability writer David Roberts called a “soup-to-nuts lifecycle analysis.” My look under the hood revealed a huge pile of nuts that’s left out: nearly all of the carbon flows into and out of forests harvested to supply CLT manufacturing plants with lumber. One of my expert sources calls that a “gaping hole” in the industry’s standard carbon-counting methodology.
It’s a particularly egregious gap for CLT assembled from lumber from British Columbia, where timber firms remove far more carbon every year than BC’s fire and infestation-ravaged forests can regrow.