A new study looks at the green growth policies articulated in major reports by the World Bank, the OECD and the UN Environment Programme, testing them against empirical evidence and models of the relationship between GDP and material footprint as well as CO2 emissions.

For material footprint, the question is whether we can achieve absolute decoupling of GDP from resource use. The study’s findings show that empirical projections show no absolute decoupling at a global scale, even under highly optimistic conditions. In addition, it suggests that, while some models show that it may be achieved in high-income nations under highly optimistic (and indeed unrealistic) conditions, this cannot be sustained in the long-term given limits to efficiency improvements.

These results assume current levels of GDP growth, of around 2-3 percent per year. They consider that it may be feasible to achieve absolute reductions in resource use with GDP growing at less than 1 percent per year. However, to achieve reductions rapid enough to get us down to safe thresholds will require degrowth strategies.

For CO2 emissions, the question is whether we can reduce emissions fast enough to stay within the carbon budgets for 1.5 degrees Celsius or 2 degrees, as per the Paris Agreement. Researchers state that emissions reductions in line with 2C are only feasible if global GDP growth slows to less than 0.5 percent. Likewise, they indicate that reductions for 1.5 degrees are only feasible in a degrowth scenario. These results hold even under optimist policy conditions, with high taxes on carbon and fast rates of technological innovation.

In other words, while we need all the government policy interventions and technological innovation we can get, any successful attempt to achieve adequate emissions reductions will require that we scale down aggregate energy demand.

In light of these results, the study suggests that green growth policy lacks empirical support. The evidence opens up questions about the legitimacy of World Bank and OECD efforts to promote green growth as a route out of ecological emergency. Any policy programs that rely on green growth assumptions—such as the Sustainable Development Goals—need urgently to be revisited, according to the study.

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