Looks like we narrowly avoided a scorched-Earth scenario.
If it weren't for a global ban of ozone-destroying chemicals in the late 1980s, the ravages of climate change would have become far worse by the 2040s than is currently projected, according to a recent study published in the journal Nature.
Luckily, this isn't what happened. But if CFCs had continued to rise, the 21st century would have seen CO2 levels rise by up to 50%.
Continued CFC emissions would have raised CO2 levels by at least 40%
The study presents models of a nightmarish scorched-Earth scenario even more dangerous than today's climate crisis. The results projected the continued surge in chlorofluorocarbons (CFCs) would have caused a global collapse in the ozone layer by the 2040s, exposing the planet's surface to harmful ultraviolet radiation, wreaking havoc on plants and animals. The global treaty to ban these chemicals, which is called the Montreal Protocol, prevented what researchers now think would have removed 60% of the ozone coverage over the tropics by the year 2100, creating a hole that would dwarf the one seen above Antarctica in the early 1980s.
These levels of mass exposure to radiation would probably damage plant tissues, substantially impairing their ability to photosynthesize and grow in regions around the world, with some areas drastically more affected than others. By the year 2100, the researchers project that the ozone layer's collapse from abundant CDCs would have prevented soils, forests, and vegetation broadly from absorbing 580 billion metric tons of carbon dioxide, increasing atmospheric CO2 levels by 40% to 50%. This would slap another 1.4°F (0.8°C) of warming onto current real-world projections by the end of the 21st century. CFCs are potent greenhouse gases, and, had the world not banned them in the eighties, researchers fear that they would have increased global temperatures by another 3°F (1.7°C) by 2100.
Constant vigilance on CFC prohibition is necessary
In sum, that represents 4.5°F (2.5°C) of warming climate that humanity narrowly avoided by staying true to the Montreal Protocol. Today, scientists, some politicians, and possibly some industry leaders are working to slow fossil fuel emissions to avoid temperatures rising by 2°C. One hesitates to imagine the carnage more than twice this limit would create in the 21st century. And, thanks to the Protocol, we might have a shot at avoiding the worst-case scenarios of climate change. "A world where these chemicals increased and continued to strip away at our protective ozone layer would have been catastrophic for human health, but also for vegetation," said Paul Young of Lancaster University, in an embargoed release. "The increased UV would have massively stunted the ability of plants to soak up carbon from the atmosphere, meaning higher CO2 levels and more global warming."
However, climate catastrophe isn't finished with us yet. Fossil fuel emissions still abound the world, and falling back on our global commitment would put us right back on track for a nightmare scenario this century. If the Montreal Protocol is disregarded, it would substantially undermine ongoing efforts to curb the effects of climate change, and reverse the healing process of the ozone layer (which is nearly complete). But, this is something that calls for constant vigilance. Probably, forever.