Major economies are overstating how much carbon their forests can absorb in a climate accounting fudge that could allow them to use even more fossil fuels.
The assessment singled out Brazil and Australia, and warned a lack of rules around accounting for forests and other land-based carbon sinks meant countries could “game the system” when reporting their national greenhouse gas emissions.
Scientists are still unclear about how carbon sinks might behave as the planet warms in future, and exactly how much heat-trapping carbon dioxide they might soak up from the atmosphere.
But that has not stopped countries from making their own assumptions and using those numbers in their national climate plans, which are due to be finalized to 2035 before the next UN climate talks in Brazil in November.
Climate Analytics, a policy institute that independently assesses these plans, said overly optimistic assumptions about how much CO2 forests might draw down was “masking the scale and pace of the fossil fuel emissions cuts needed”.
In the latest versions of its climate plan, Australia had leaned so heavily on forests to reduce its carbon footprint that it would amount to scaling back real cuts to emissions by 10%, Climate Analytics said.
While forests will be crucial to global efforts to reduce planet-heating emissions, these estimates should be listed separately and not used to “offset” energy and industry emissions, he said.
That is because the complex processes by which forests and other land sinks absorb carbon are not as well understood as the role of fossil fuels in driving climate change.