The foundational materials of the past century are energy-intensive and polluting. The production of steel is responsible for 7 to 9 percent of global carbon emissions. The cement industry produces about 8 percent. Efforts are underway to make “green” steel and concrete, but a full transformation is still years away.
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“This is what we have: concrete, steel, masonry and wood. That’s it. And the only path forward to get us to carbon-neutral buildings is timber,” said Green, who designed the seven-story T3 building in Minneapolis, completed in 2016, using timber salvaged from trees killed by beetles.
Trees. Those huge, carbon sequestering plants which we are already cutting down faster than we can grow them? The large, tall stands prized for high strength in glulam and clt layups which are processed in enormous, energy-intensive plants with toxic adhesives? The percentage of energy used for steel and concrete is what it is, in part, due to the vast advantage in square feet constructed using these products. And energy use? Steel production at the mill can be virtually 100% recycled and 100% electric. How much post-use wood is actually being recycled into building products? Close to none.
Mining for iron and cement is certainly not carbon free, but neither is cutting down forests which are actively sequestering carbon. Harvesting beetle damaged trees is absolutely worthwhile, but there aren’t enough to supply even a small fraction of world building demand.
Exactly, this sounds like carbon offsets. Let’s pretend we’ll plant huge forests
Still makes much more sense to build buildings or furniture from wood than to just burn it for heating and claim it’s a renewable energy source… With buildings you will at least be sure to keep that carbon out of the atmosphere for a longer period.
I think the better alternative is to not cut down the forests in the first place for either housing or fuel and let them continue to grow. Now for damaged and standing dead trees it makes sense to use them vs burning, but relative to the demand for lumber products, generally, the beetle damaged trees is a small fraction of global supply. Ideally, we’ll stop seeing beetle damage trees, but that would require that we slow down or stop climate change as the beetle problem is one of expanding beetle territory (which the trees can’t move to avoid).
High rises aren’t efficient, but
“ The sweet spot for mass timber, he argued, is not a showy high-rise but the vast number of mid-rise buildings: schools, apartment blocks, auditoriums, sports arenas, warehouses, bus depots and office parks
