More Montreal Magic ...
... and we thought skin cancer was the main problem!
A Recent paper in Nature, authored by several of my close colleagues, added another thread to how the Montreal Protocol saved the world. It makes the UV and skin cancer angle pale (if you’ll excuse the pun) into insignificance.
As Nature’s commentary on the paper says, “the 1987 Montreal Protocol, which effectively banned ozone-killing chemicals, played a significant part in protecting the planet’s ability to absorb carbon. In a chilling scenario of what might have been, researchers estimated that, without the protocol, increasing production of chlorofluorocarbons and other ozone-depleting substances would have contributed to global air temperatures rising by an additional 2.5 °C by the end of this century. The ozone layer would have collapsed by the 2040s. And the resulting damage to vegetation would have led to 580 billion tonnes less carbon stored in forests, other vegetation and soils by 2100”.
That’s in addition to the warming effect of CFCs (and their replacements) that I discussed in a recent post.
I’ve discussed before the dire consequences to humans without the Montreal Protocol. But at least we can take refuge from UV indoors, unlike plants. They have to just suck it up.
The findings of the new paper are nicely summarised in their final figure, reproduced below.
The figure shows that by the end of the century, the increases in UV caused by ozone collapse would have decimated plant growth and seriously curtailed their ability to capture CO2 through photosynthesis. So CO2 levels would have by then been around twice those that are currently anticipated (as shown in the left panel). That increased CO2 would in turn have led to temperatures around 2.5 C warmer by year 2100. Without the Montreal Protocol, increases in temperature over the period 1980 to 2100 would have been about twice that currently expected (right panel). The Montreal Protocol has saved us from runaway greenhouse warming.
Flow-on effects are even more dire. The reduced primary production would have led to disruptions of food chains which would threaten the very survival of much of the animal kingdom, including billions of humans.
Well done Montreal! You saved our bacon.
Thanks for reading this. Previous posts on the intersection between Ozone, UV, Climate, and Health can be found at my UV & You area at Substack. Click below to subscribe for occasional free updates.