Humanity would have a 64% chance of keeping average global warming under the crucial 1.5°C threshold if all fossil infrastructure were replaced with zero-carbon alternatives at the end of its operating life, according to a new study in the journal Nature Communications.
The study “shows that meeting the internationally agreed aspiration of keeping global warming to less than 1.5°C above pre-industrial levels is still possible,” The Guardian reports. “The scientists say it is therefore the choices being made by global society, not physics, which are the obstacle to meeting the goal.”
“It’s good news from a geophysical point of view,” said lead researcher Christopher Smith of the University of Leeds. “But on the other side of the coin, the [immediate fossil fuel phaseout] is really at the limit of what we could possibly do. We are basically saying we can’t build anything now that emits fossil fuels.”
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“We are rapidly approaching the end of the age of fossil fuels,” said renowned climate economist Lord Nicholas Stern of the London School of Economics, who was not involved with the research. “This study confirms that all new energy infrastructure must be sustainable from now on if we are to avoid locking in commitments to emissions that would lead to the world exceeding the goals of the Paris Agreement.”
“Whether it’s drilling a new gas well, keeping an old coal power station open, or even buying a diesel car, the choices we make today will largely determine the climate pathways of tomorrow,” said University of Edinburgh carbon management specialist Dave Reay. “The message of this new study is loud and clear: act now or see the last chance for a safer climate future ebb away.”
The modelling behind the study assumed average lifespans of 40 years for a power plant, 15 years for a car, and 26 years for a plane. “The work also assumes a rapid end to beef and dairy consumption, which is responsible for significant global emissions,” The Guardian notes.
“In this scenario, the models suggest carbon emissions would decline to zero over the next four decades and there would be a 64% chance of the global temperature rise remaining below 1.5°C,” writes Environment Editor Damian Carrington. “If the phaseout does not begin until 2030, the chance is 33%.” The analysis left out possible tipping points, like massive methane releases from Arctic permafrost, that could trigger runaway atmospheric warming.
Smith told The Guardian he believes average global warming will reach 2.0 to 2.5°C, given the slow pace at which decarbonization efforts are unfolding. But “if you don’t have a goal, you are not going to get anywhere. If you have a target that is really hard to achieve and you miss it slightly, that is better than wandering aimlessly into a future climate that is no good for anybody.”