The Worst-Case Climate Change Scenarios Have Just Been Debunked
For the past decade, the fight against climate change has been driven by the knowledge that we're racing against the clock: If something drastic doesn't happen, human civilization may run into cataclysmic weather changes by the end of the century. Much of this stems from the UN's projection that the global temperature will rise between 1.5 and 4.5 Celsius, or 2.7 to 8.1 degrees Fahrenheit, however—and a new study from the University of Exeter may have proven that projection to be off the mark.
The key factor in the new study is "equilibrium climate sensitivity," which is the estimate for how much the global temperature will increase if the amount of CO2 in the atmosphere doubles. Previously, the UN estimate was considered the best projection, but the University of Exeter has ruled two potential scenarios: one in which the world is less sensitive to increased CO2, and one where the Earth is extremely sensitive. Both of these scenarios account for the wide range between the UN's original projections.
Instead, the new study says that a better forecast for equilibrium climate sensitivity is between 2.2 and 3.4 degrees Celsius, with the most likely temperature increase being 2.8 C, or 5 F.
This isn't a call to abandon climate change efforts—in fact, it may mean that they'll be more effective than we hoped. If the UN's direst projections were true, climate change's most destructive effects were already inevitable and irreversible.
If this new study is accurate, we won't be dealing with a doomsday scenario in the coming century. That means more time to mitigate the effects of CO2 emissions, develop new technologies, and explore the solar system, including planetary colonization.
However, there is one caveat: according to the scientists who worked on the new study, the Earth can still reach significant "tipping points" that abruptly and drastically accelerate climate change. One such tipping point is the melting of the polar ice caps, while the second big one is the breakdown of the Gulf stream.
Even if the CO2 in the atmosphere is kept at manageable levels, the erosion of these systems can still happen, and that means huge consequences for the entire planet.