According to a new study, building new urban homes from wood instead of concrete and steel could save around 10% of the carbon budget needed to limit global warming to 2°C this century.
The overhaul of construction practices necessary for such a change would require up to 149 million hectares of new timber plantations – and increased harvesting from unprotected natural forests – but there is no need to encroach on the agricultural land, according to the article by the Potsdam Institute for Climate Impact Research (PIK).
Housing 90% of the world’s growing urban population in mid-rise wooden buildings could prevent 106 billion tonnes of carbon emissions by 2100, according to research.
Abhijeet Mishra, the lead author of the paper, said, “More than half of the world’s population currently lives in cities and by 2100 this number will increase significantly. This means more homes will be built with steel and concrete, most of which have a large carbon footprint. But we have an alternative. We can house the new urban population in mid-rise buildings – that is, 4 to 12 floors – made of wood.
The study, published Tuesday in Nature Communications, is the first to analyze the magnitude of possible emission reductions from a large-scale transition to “wood cities.”
Using four different land use scenarios, PIK scientists used the open source global land use model Magpie to explore the impacts and practicalities of the idea of “wooden cities”.
Their reasoning was that wood has the lowest carbon footprint of any building material because the carbon dioxide absorbed during tree growth will not be emitted until the wood is eventually destroyed.
Alexander Popp, co-author of the study, said preventing logging in primeval forests and biodiversity conservation areas was crucial to their calculations.
“Explicit safeguarding of these protected areas is essential, but establishing timber plantations at the expense of other unprotected natural areas could further increase future biodiversity loss,” he said.
Environmentalists, however, point out that the world’s 131 million hectares of tree plantations tend to be less biodiverse than natural forests and burn more easily.
Sini Eräjää, head of Greenpeace’s European Food and Forests Campaign, said it would be “a terrible idea” to cut down natural forests and replace them with timber plantations.
“It would be a disaster for nature and for the climate,” she said. “Natural, biodiverse forests are more resilient to drought, fire and disease, and therefore a much safer store of carbon than the tree plantations we saw go up in smoke this summer from Portugal to California Wood may play a bigger role in building, but doubling the world’s tree plantings at the expense of priceless nature is just bonkers, while modest cuts in meat and dairy production free up the necessary land.
Mishra admitted wildlife loss will occur with tree plantings and called for “strong governance and careful planning to limit negative impacts on biodiversity”.
“Biophysical risks” such as the potential for more wildfires in the city were not assessed in the report, he added.
Wood is still preferred by homebuilders in the United States, but as wildfires have intensified amid worsening weather disruption, some have questioned the practice of building with flammable materials.
Abhilash Panda, Deputy Head of Partnerships at the UN Office for Disaster Risk Reduction in Geneva, said: “Wood offers benefits. It provides a carbon sink, reduces emissions and provides a way to deal with unmanaged forests. However, it is flammable. However, what matters most in determining fire risk is what type of dwelling is being considered, who is the target, and what is the location. Risk is location specific and any design must incorporate resilience there. »
Around 15 billion trees are currently cut down each year worldwide. It is believed that the planet’s tree population has almost halved since the dawn of human civilization.
Wood cities “could reduce 100 billion tons of CO2 emissions by 2100”