1987 Montreal ozone guidelines maintain again the acute international warming of the “scorched earth” – watts with that?
Guest contribution by Eric Worrall
According to a new study, the Montreal Protocol protects plants’ ability to absorb CO2 and prevents global warming from rising by 0.8 ° C.
Scientists reveal how a groundbreaking CFC ban gave the planet a chance against global warming
August 18, 2021 4:01 PM
Without the global CFC ban, we would already be faced with the reality of a “scorched earth”, according to researchers who measure the effects of the Montreal Protocol.
Their new evidence shows that if we continued to use ozone-depleting chemicals like CFCs, the planet’s critical ability to absorb carbon from the atmosphere would have been massively compromised and global temperatures could skyrocket.
New modeling by the international team of scientists from the UK, US and New Zealand, published today in Nature, paints a dramatic vision of a scorched planet earth without the Montreal Protocol, what they call “The World Avoided.” This study creates a new strong link between two major environmental problems – the hole in the ozone layer and global warming.
Their results, outlined in the paper “The Montreal Protocol Protects the Terrestrial Carbon Sink”, show that the ban on CFCs has protected the climate in two ways – by curbing their greenhouse effect and by protecting the ozone layer by protecting the plants from the harmful increases in ultraviolet radiation (UV). Crucially, this protected the plant’s ability to absorb and lock in carbon dioxide from the atmosphere, thus preventing further acceleration of climate change.
Overall until the end of this century without the CFC ban of the Montreal Protocol:
· Forests, other vegetation and soils would have stored 580 billion tons less carbon.
· Depending on the future fossil fuel emissions scenario, there would be an additional 165-215 ppm CO2 in the atmosphere. Compared to today’s 420 parts per million CO2, this is an additional 40-50%.
· The enormous amount of additional CO2 would have contributed to an additional warming of 0.8 ° C due to its greenhouse effect.
Read more: https://www.lancaster.ac.uk/news/scientists-reveal-how-landmark-cfc-ban-gave-planet-fighting-chance-against-global-warming
The abstract of the study;
The Montreal Protocol protects the terrestrial carbon sink
Paul J. Young, Anna B. Harper, Chris Huntingford, Nigel D. Paul, Olaf Morgenstern, Paul A. Newman, Luke D. Oman, Sasha Madronich & Rolando R. Garcia
The control of the production of ozone-depleting substances by the Montreal Protocol means that the stratospheric ozone layer recovers1 and a resulting increase in harmful ultraviolet surface radiation is avoided2,3. The Montreal Protocol has other advantages in mitigating climate change, as ozone-depleting substances are powerful greenhouse gases4,5,6,7. Avoided ultraviolet radiation and climate change also have benefits for plants and their ability to store carbon through photosynthesis8, but this has not yet been explored. Here, using a modeling framework that couples ozone depletion, climate change, plant damage from ultraviolet radiation, and the carbon cycle, we investigate the benefits of an avoided increase in ultraviolet radiation and climate change in the terrestrial biosphere and its capacity as a carbon sink. Taking into account a number of strengths for the effect of ultraviolet radiation on plant growth8,9,10,11,12 we estimate that by the end of this century (2080.) There could be 325–690 billion tons less carbon in plants and soils – 2099) without the Montreal Protocol (compared to climate projections with controls for ozone-depleting substances). This change could have resulted in an additional 115–235 parts per million atmospheric carbon dioxide, which could have increased the global mean surface temperature by 0.50–1.0 degrees. Our results suggest that the Montreal Protocol can also help mitigate climate change by avoiding reducing the carbon sink on land.
Read more: https://www.nature.com/articles/s41586-021-03737-3
Obviously there isn’t a lot of wheat production in Antarctica, so at the top of the page is a historical graph of Australian wheat production. Personally, I cannot see any obvious evidence of significant UV damage to production during the period when the southern ozone hole was at its greatest extent in the 1990s.