Global wood harvests will add 3.5 to 4.2 billion tonnes of CO2 yearly in coming decades: Report

This level of emissions is more than three times the annual emissions from aviation and equals common estimates of the emissions from deforestation and other land use change due to agricultural expansion
Photo: iStock
Photo: iStock
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The world’s wood harvests will add 3.5-4.2 billion tonnes of carbon dioxide (CO2) yearly over the coming decades, more than 10 per cent of recent global annual emissions of carbon dioxide, according to a new study.

This level of emissions is more than three times the annual emissions from aviation and equals common estimates of the emissions from deforestation and other land use change due to agricultural expansion, the study noted.

The study was led by World Resources Institute (WRI), a global research organisation. It was published online in the journal Nature on July 5, 2023.

Substituting steel and concrete for wood in half of new buildings across Africa would result in cumulative net negative carbon emissions of 5-10 gigatonnes of CO2 equivalent by 2050 in the continent’s construction sector, according to a new research commissioned by International Institute for Environment and Development (IIED).

According to researchers, these emissions are typically not counted in both, scientific papers and public policies.

The WRI study found that CO2 emissions from wood harvests will grow due to rising global demand for wood, as more trees are used for fuel and for  making buildings, furniture and paper products.  

The global demand for wood is projected to grow at 54 per cent from 2010 to 2050 — to 5.7 billion cubic metres in 2050, from 3.7 billion cubic metres in 2010.

As a result, the study projects carbon dioxide emissions will increase by roughly one-third — to around five billion tonnes in 2050, from around three billion tonnes in 2010.

Globally, trees store a tremendous amount of carbon in their trunks, branches and roots. When they are cut down, the stored carbon can be released over time or rapidly if the wood is burned.

The researchers in the WRI study used a new global forest carbon model, the carbon harvest model (CHARM), which builds on a long-established approach  of counting the effect of wood harvests on changes in atmospheric carbon over time as carbon shifts among different storage pools.

Pools include live vegetation, roots, different wood products and landfills.

The effect on atmospheric carbon is the difference between carbon stored in all pools due to the harvest and the carbon that forests would store if left unharvested and continued to grow.

The paper estimates that significant mitigation of these emissions could occur if people reduce their uses of wood for energy use, harvest larger trees in the tropics in ways that kill fewer smaller trees and increase the growth rate of already existing plantation forests.

According to a study published in the journal Science, by removing human intervention (like wood harvesting) under current climatic conditions and with the CO2 concentration that already exists, their above ground biomass could increase by up to 44.1 gigatonnes of carbon.

Tim Searchinger, an author of the WRI study and technical director for Agriculture, Forestry and Ecosystems at WRI said: “By correctly estimating these emissions, we hope to encourage the forest products industry and its consumers to find more ways to grow and use wood more efficiently to reduce these emissions.”

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