Most of the world’s human population, and the health of ecosystems across the planet, could face an existential threat by the end of the century if rapid, forceful action is not taken to combat climate change. According to a new study published in Proceedings of the National Academy of Sciences, there is now a 1-in-20 chance that climate change will cause an “existential/unknown” warming effect, defined in the study as a global temperature rise of 5 degrees Celsius over pre-industrial levels, that would have a devastating impact on humanity while wiping out 20 percent of life on Earth.
Even as climate change is apparent in the present, its worst impacts will be felt by future generations. “To put in perspective, how many of us would choose to buckle our grandchildren to an airplane seat if we knew there was as much as a 1 in 20 chance of the plane crashing?” said co-author Veerabhadran Ramanathan of University of California San Diego. “With climate change that can pose existential threats, we have already put them in that plane.” In addition to the 5 percent chance of complete societal, and perhaps species, collapse, the scientists estimate that, if action is not taken, there is a 50 percent chance of a 4 degree temperature rise by 2100, far surpassing the 2 degree goal set by the Paris accord.
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The study is not all doom and gloom. The scientists describe several actions that can and must be taken, including achieving peak global emissions by 2020 and carbon neutrality by 2050, ending the use of short-term climate pollutants like hydrofluorocarbons, and removing carbon and other greenhouse gases from the atmosphere through sequestration, reforestation and other methods. The study was utilized by 33 policy and science experts in crafting a related report which further details actions that can be taken now. Whether the advice will be taken remains to be seen.
Images via Christopher Michel and Ian D. Keating
So: A five percent risk of societal collapse due to GW? More likely a 90% chance of societal adaptation to this menace.