Study: Surveyed climate experts believe world may achieve net-zero emissions by 2100

09 / 10 / 2024

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A study – based on a survey of more than 200 authors of reports from the Intergovernmental Panel on Climate Change (IPCC) – said more than two-thirds of surveyed respondents believe the world may achieve net-zero emissions of carbon dioxide during the second half of this century, according to Stanford University. 

This indicates some optimism that mitigation efforts may be starting to bend the emissions curve toward what would be needed to achieve the Paris Agreement’s temperature goal.

“These experts’ answers are consistent with the success and further strengthening of current climate policies, which may be encouraging to those concerned about the negative impacts of climate change that we’re already seeing,” said study co-author Steve Davis, a professor of Earth system science at the Stanford Doerr School of Sustainability.

A majority of survey respondents also acknowledged the potential for removing carbon dioxide from Earth’s atmosphere, with a median response indicating belief that the technology could remove up to five gigatons of carbon dioxide annually by 2050. That is at the lower end of the range believed to be necessary to meet the 2015 Paris Agreement’s goal of keeping global warming well below 2 degrees Celsius above pre-industrial levels, and preferably below 1.5 degrees Celsius.

“We wanted to survey some of the top climate experts in the world to get some insight into their perceptions of different future climate outcomes,” said lead study author Seth Wynes, an assistant professor of geography and environmental management at the University of Waterloo. “These scientists also engage in important climate change communication, so their optimism or pessimism can affect how decision-makers are receiving messages about climate change.” 

The 211 survey respondents were generally pessimistic about the likelihood of reaching the Paris targets given current policies, with 86% estimating warming above 2 degrees Celsius by 2100. The median estimate was 2.7 degrees Celsius, which is expected to have catastrophic consequences for people and the planet.

Co-author Damon Matthews, a professor in Concordia University’s Department of Geography, Planning and Environment, noted that this does not mean such extreme warming is inevitable.  “These responses are not a prediction of future warming, but rather a gauge of what the scientific community believes. The answers are surprisingly consistent with previous estimates of what would happen if our current climate policies continued without any increase in ambition, which range from about 2.5 to 3 C,” he said.

Along with questions about the likelihood of future climate outcomes, the respondents were also asked to estimate their peers’ responses to the same questions. 

“There was a strong correlation between what people believe and what they sense their peers believe,” Wynes said. “They had a bias to see their beliefs as representative of the larger group. This can indicate an overconfidence in their own beliefs, so we think this is a good opportunity for them to reevaluate what their peers actually believe.”