Of the 7.7 billion humans on earth, more than half inhabit urban areas, and this number is predicted to rise in the coming years. According to a 2018 United Nations projection, more than 68% of the global population will occupy urban spaces like towns and cities. Cities will have to ramp up housing construction to accommodate this increasing population.

However, with global warming and climate change looming large, construction faces a serious challenge as steel and concrete have a massive carbon footprint. To address this issue, a group of scientists from the Potsdam Institute for Climate Impact Research, New York, suggested substituting these traditional construction materials with wood in a recent study. Published recently in Nature Communications, their research made a case for wooden cities on the basis of wood’s low carbon footprint and the fact that timber doesn’t produce any extra carbon dioxide till the timber is completely destroyed.

Environmentalists, however, have voiced criticism of the idea, noting that shifting the bulk of construction to wood will require huge tracts of timber plantations, that threaten to destroy biodiversity. Sini Eräjää, Greenpeace’s Food and Forests Campaign Lead in Europe, told The Guardian that the study’s suggestion “to double the world’s tree plantations at the expense of priceless nature is just bonkers when modest reductions in meat and dairy farming would free up the land needed.”

The research and the environmentalists’ reaction then highlight two different strands of approach in answering the climate question. While the climate researchers in the current study center human growth and housing in their research, Eräjää’s reaction points to a greater concern for environmental interdependence and how human consumption is harming this. Biodiversity loss represents an upset to delicate ecologies that sustain life on Earth.

For their study, the researchers used a framework that helps assess land distribution and competition for resources in future scenarios of rising population and material demand. Titled ‘Model for Agricultural Production and its Impact on the Environment’ (MAgPIE), the model also examines the consequences for sustainable development and climate change impacts in these scenarios. According to MAgPIE, switching to mid-rise (4-12 floors) houses made of timber instead of steel and concrete could prevent up to 106 billion tons of carbon emissions by 2100.

As a natural carbon sink, wood has the least carbon footprint among all construction materials. It is already the most common material used for building houses in the US.

Related on The Swaddle:

India Wants to Build Smart Cities. We Asked Experts if These Urban Designs Can Survive the Climate Crisis

Yet, environmentalists point out that shifting to wood for construction to bring down carbon emissions comes with its own environmental concerns. The biodiversity risks associated with homogenous timber plantations aside, wood is combustible, which would keep both timber plantations and timber cities at a higher fire risk than current urban areas. The current research does not assess the possibility of city wildfires and other “bio-physical risks.” City wildfires could significantly raise the amount of carbon dioxide in the air.

In a press release, the authoring scientists acknowledged the risks to the environment and biodiversitythat the transition to wood for mass construction could cause, and called for “strong governance and careful planning to limit negative impacts to biodiversity.” The authors maintained that their intention was to highlight how changing land use patterns and construction methods together “could store and reduce carbon in the atmosphere without food security or biodiversity.”

The shift to wooden cities may then be desirable or realistically able to help reduce carbon emissions in the atmosphere only if followed up with ample regulations to protect existing natural forests and biodiversity. But the tussle between environmentalists and technocratic sustainability solutions represents a bigger problem with respect to our climate response: that dialogue among all stakeholders is critical to achieving sustainability that’s equitable.