Robert Perschel: What will our carbon-neutral cities of the future be made of?

Jun. 07, 2023

To address our housing crisis and climate crisis, we know we need more dense housing near transit. But the multistory building materials we primarily rely on today, steel and concrete, are extremely carbon-intensive.

The building sector has a very large environmental footprint, producing 40% of global carbon emissions annually. We need to talk about how to build a cleaner future.

One key approach is to use more natural, biologically based renewable materials that lower the pollution of the atmosphere with carbon. Wood is a beautiful, time-tested material that can be used quickly and affordably to meet housing needs, as well as grown in ways that protect forests and store more carbon.

In addition, we now have new technological advances that allow us to use wood to build tall buildings. These components are made by joining smaller pieces of wood together and are called mass timber.

A form of mass timber known as cross-laminated timber allows for taller multifamily apartments and offices and it’s taking off around the world. Just last year, a 25-story office tower opened in Milwaukee, breaking the record for the world’s largest mass timber building. Harvard University has announced plans for the David Rubenstein Treehouse, a mass timber conference center. And in Maine, the Portland Museum of Art is using mass timber for its $100 million expansion.

What’s revolutionary about mass timber is that it allows softer and smaller pieces of wood to be pressed together into structures that are affordable, attractive, sturdy and fire-resistant. And critically, it has a much lower life-cycle carbon footprint than steel and concrete, delivering a 26.5% reduction in global warming potential, according to University of Washington researchers.

Key to maximizing the carbon benefits is making sure the wood is harvested thoughtfully, following the principles of sustainable forestry that are focused on ensuring a healthy, regrowing forest post-harvest, and using that wood to substitute for materials that carry a far greater environmental impact from their extraction and manufacturing.

A holistic approach to forest management and climate mitigation in New England forests could keep more than 646 million metric tons of CO2 out of the atmosphere over the next 30 years, according to analysis from the New England Forestry Foundation. This represents nearly one-third of the total energy-related CO2 emissions reductions needed across New England by 2050.

Similarly, a report from Highstead shows properly managed forests could sequester 21 percent of New England’s carbon emissions while also enhancing critical co-benefits, such as cleaner air and water, greater recreational opportunities, and jobs.

We’re seeing important steps forward on the federal level. The Inflation Reduction Act encourages climate-smart forestry, providing low-cost financing to forestland owners to implement carbon-aligned forest management. And the U.S. Department of Agriculture’s Climate-Smart Commodities program is piloting climate-smart forestry to produce climate-smart wood, drive greenhouse gas reductions, and build new markets for low-carbon products.

Building those markets is so critical because what’s good for our climate can also help grow our local economies. Here in New England, forests contribute more than $13 billion annually to local and regional economies, and sustain over 50,000 jobs in the woods, mills, and supporting services.

And because mass timber sections can be designed exactly to specifications, minimizing on-site construction and waste, our cities could see the economic benefits of faster, more efficient structures. “Mass timber buildings are roughly 25% faster to construct than concrete buildings and require 90% less construction traffic,” according to the softwood lumber industry.

What we need now is to incentivize and encourage mass timber as a go-to building material, including in our building codes, and sourcing those materials in a sustainable way that minimizes negative environmental impacts and maximizes benefits to nature and society. If we get it right, we’ll see the rise of a new, cleaner city.

This commentary is by Robert Perschel, executive director of the New England Forestry Foundation.