Study Shows Nations Need to Make Net-Zero Targets Legally Binding to Ensure Implementation

A recent study conducted by researchers from Imperial College London and published in Science has found that almost 90% of global net-zero greenhouse gas emissions pledges have low confidence in their full implementation. The study suggests that nations need to make their targets legally binding and back them up with long-term plans and short-term implementation policies to increase the likelihood of avoiding the worst impacts of climate change. The researchers assessed 35 net-zero targets covering every country with more than 0.1% of the current global greenhouse gas emissions.

Lead researcher Professor Joeri Rogelj, director of research for the Grantham Institute at Imperial, says that most countries do not provide high confidence that they will deliver on their commitments. “Climate policy is moving from setting ambitious targets to implementing them,” he says. “The world is still on a high-risk climate track, and we are far from delivering a safe climate future.”

The Paris Agreement

Climate goals set out in the Paris Agreement include keeping temperature rises well below 2°C above the average temperature before the industrial revolution and ideally below 1.5°C. The main way to achieve this is to reach net-zero greenhouse gas emissions as soon as possible, where any remaining emissions are effectively offset. Most countries have set net-zero goals and Nationally Determined Contributions (NDCs), non-binding national plans proposing climate actions.

Taking these plans at face value, and assuming they will all be fully implemented, gives the world a chance of keeping warming to 1.5 to 2⁰C. But taking current policies only, with no implementation of net-zero pledges, means models predict temperature rises could be as much as 2.5 to 3⁰C by 2100, with warming still increasing.

Confidence Assessment

The study assigned a “confidence” to each net-zero policy, based on three policy characteristics: whether the policy was legally binding, whether there was a credible policy plan guiding implementation, and whether short-term plans would already put emissions on a downward path over the next decade. Policies were given “higher,” “lower,” or “much lower” confidence of being fully implemented.

Some regions scored highly, including the European Union, the United Kingdom, and New Zealand, but around 90% of policies scored lower or much lower confidence, including China and the US, which together account for more than 35% of current emissions. From this assessment, the team modeled five scenarios of future greenhouse gas emissions and resulting temperatures.

Legally Binding Targets

The most optimistic scenario has a range of 1.6 to 2.1°C, with a median estimate of 1.7°C. This might suggest that if all net-zero policies are fully implemented, the Paris Agreement goals are within reach. However, with so many policies ranked in the low-confidence end of the scale, this would be wishful thinking in the absence of further efforts.

Co-author Taryn Fransen, from the World Resources Institute in Washington DC, says, “Climate change targets are by their nature ambitious—there’s no point in setting a target for a foregone conclusion. But implementation must follow.” Only twelve out of 35 net-zero policies are currently legally binding, and the researchers say increasing this number would help ensure the policies survive long-term and catalyze action. Countries also need clear implementation pathways for different sectors, outlining exactly what changes are needed and where the responsibility lies.

Co-author Dr. Robin Lamboll, from the Center for Environmental Policy at Imperial, says, “Making targets legally binding is crucial to ensure long-term plans are adopted. We need to see concrete legislation in order to trust that action will follow from promises.”

The study concludes that nations need to make their net-zero targets legally binding and back them up with long-term plans and short-term implementation policies to increase the likelihood of avoiding the worst impacts of climate change. The researchers recommend that countries provide high confidence that they will deliver on their commitments to achieve the Paris Agreement goals.