For More and More Scientists, Climate is an “Emergency”

Our path has gone from Bunny Slope to beyond Double Black Diamond.

Washington Post:

On Monday, scientists released a paper showing that the world’s “carbon budget” — the amount of greenhouse gas emissions the world can still emit without boosting global temperatures more than 1.5 degrees Celsius — has shrunk by a third. The world only has 6 years left at current emissions levels before racing past that temperature limit.

“There are no technical scenarios globally available in the scientific literature that would support that that is actually possible, or can even describe how that would be possible,” Joeri Rogelj, a climate scientist at Imperial College London, told reporters in a call.

Tim Lenton, one of the co-authors on Ripple’s most recent paper and a professor of earth system science at the University of Exeter, said that 2023 has been filled with temperatures so far beyond the norm that “they’re very hard to rationalize.” “This isn’t fitting a simple statistical model,” he said.

Nature – Assessing the Size and Uncertainty of Remaining Carbon Budgets:

The remaining carbon budget (RCB), the net amount of CO₂ humans can still emit without exceeding a chosen global warming limit, is often used to evaluate political action against the goals of the Paris Agreement. RCB estimates for 1.5 °C are small, and minor changes in their calculation can therefore result in large relative adjustments. Here we evaluate recent RCB assessments by the IPCC and present more recent data, calculation refinements and robustness checks that increase confidence in them. We conclude that the RCB for a 50% chance of keeping warming to 1.5 °C is around 250 GtCO₂ as of January 2023, equal to around six years of current CO₂ emissions. For a 50% chance of 2 °C the RCB is around 1,200 GtCO₂. Key uncertainties affecting RCB estimates are the contribution of non-CO₂ emissions, which depends on socioeconomic projections as much as on geophysical uncertainty, and potential warming after net zero CO₂.

Post again:

The language has spilled into academic publications as well. As recently as 2015, only 32 papers in the Web of Science research database included the term “climate emergency.” In 2022, 862 papers contained the phrase.

It wasn’t always this way. In the 2000s and even early 2010s, most scientists shied away making any statements that could be seen as “political” in nature. Jacquelyn Gill, a professor of climate science and paleoecology at the University of Maine, said that when she was doing her PhD in the late 2000s, senior academics warned her against deviating at all from the science when interacting with the media or the public.

“We were actively told if we start to talk about solutions, if we start to talk about the policy implications of our work, we will have abandoned our supposed ‘scientific neutrality,’” Gill said. “And then people will not trust us anymore on the science.”

Susan Joy Hassol, a science communication expert who has worked with climate researchers for years, says that even a decade ago, climate scientists were uncertain what their role was in communicating the dangers of rising temperatures. “I think at least some of them felt that scientists communicate through IPCC reports,” Hassol said, referring to the United Nations Intergovernmental Panel on Climate Change. “‘We do our science, we publish, we put together these reports, and it’s kind of up to other people to listen.’”

Now, she said that has changed. “We have reached this stage of crisis,” she said.
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Hassol said that the shift is simple. In the 2000s, she said, climate change wasn’t yet at the level of an emergency. She recalls a 2009 report called the Copenhagen Diagnosis, which analyzed climate science to date and made suggestions for how to reach net-zero carbon emissions. If world governments had acted swiftly, the world would have only had to cut emissions by a bit over 3 percent per year. “We called that the bunny slope,” Hassol recalled.

If, on the other hand, governments didn’t start the transition until 2020, cuts would have to be much steeper — up to 9 percent per year. “We called that the double-black diamond,” she said. Despite the brief respite in CO2 emissions during the pandemic, humanity’s trajectory has veered closer to the double-black diamond path.