Burning wood makes more CO2 than coal.
The conclusions high points:
- biomass used to displace fossil fuels injects CO2 into the atmosphere at the point of combustion and during harvest, processing and transport.
- the first impact of displacing coal with wood is an increase in atmospheric CO2relative to continued coal use
- before breakeven, atmospheric CO2 is higher than it would have been without the use of bioenergy, increasing radiative forcing and global average temperatures, worsening climate change, including potentially irreversible impacts that may arise before the long-run benefits are realized.
- biofuels are only beneficial in the long run if the harvested land is allowed to regrow to its pre-harvest biomass and maintained there.
- The carbon debt incurred when wood displaces coal may never be repaid if development, unplanned logging, erosion or increases in extreme temperatures, fire, and disease (all worsened by global warming) limit regrowth or accelerate the flux of carbon from soils to the atmosphere.
- harvesting existing forests and replanting with fast-growing species in managed plantations can worsen the climate impact of wood biofuel.
- growth in wood harvest for bioenergy causes a steady increase in atmospheric CO2 because the initial carbon debt incurred each year exceeds what is repaid.
- using wood in electricity generation worsens climate change for decades or more even though many of our assumptions favor wood