Different methods of achieving the Paris Agreement climate goals

The Paris Agreement is a global collaboration that seeks to reduce carbon emissions and stop the world’s temperature from increasing past two degrees Celsius.

While many nations are already working to implement policies that reduce carbon emissions and transition from fossil fuels to renewables, the exact temperature and emissions requirements to meet the Paris Agreement are not widely understood.

Researchers from the National Institute for Environmental Studies in Japan and the U.S. National Center for Atmospheric Research examined several new emissions and temperature scenarios to find out what exactly was needed to reduce emissions and mitigate climate change.

The new study found that meeting the Paris Agreement does not necessarily mean cutting all greenhouse gas emissions and also that even under a zero-emission scenario, temperatures could still climb higher than preferred.

Their findings highlight the uncertainty and inconsistencies that come with the Paris Agreement’s plans.

“What we found is that the two goals do not always go hand in hand,” said Katsumasa Tanaka, a lead author of the study. “If we meet temperature targets without first overshooting them, we don’t have to reduce greenhouse gas emissions to zero. But if we do reduce emissions to zero, we still might not meet the temperature targets if we don’t reduce emissions quickly enough.”

The results were published in the journal Nature Climate Change.

For the study, the researchers used an integrated assessment computer model to create and analyze ten different emissions scenarios.

The model factored in both the environmental and economic impact of temperature and emissions reductions.

“We investigated the consistency between the Paris targets in two ways,” said Brian O’Neill, a fellow lead researcher. “First, we asked, what happens if you just meet the temperature target in a least-cost way? What would emissions look like? Then we said, let’s just meet the emissions goal and see what kind of temperatures you get.”

The scenarios showed that if emissions were reduced sooner, the Earth’s temperature wouldn’t exceed two degrees Celsius.

All in all, the results showed that the biggest driver of temperature changes in the latter half of the century is when emissions are reduced.  

“The timing of when emissions are reduced really matters,” said O’Neill. “We could meet the goal set out in the Paris Agreement of reducing emissions to zero in the second half of the century and still wildly miss the temperature targets in the same agreement if we wait to take action.”

The researchers hope their work will help provide a better foundation for implementing the most effective and consistent policies under the Paris Accord.

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By Kay Vandette, Earth.com Staff Writer