THE CLIMATE BENEFITS FROM OTHER ENVIRONMENTAL SOLUTIONS

by Caroly Shumway, Ph.D.

I know at times the climate problem seems hopeless, but take heart...it's not. The climate solutions that we need already exist today. And because earth's cycles are so interconnected, solving other environmental problems helps solve climate change too.

Consider the climatic impacts of the Montreal Protocol, the international agreement to phase out ozone-depleting chemicals used in refrigerators, air conditioners, and propellants to protect the world's ozone layer, so critical to human health and the environment. Entered into force by nations in 1980, the agreement has been astoundingly successful; initial signs of healing the ozone hole over Antarctica already have been reported.

The Montreal Protocol has other benefits too. For years, scientists have worried about an ice-free event in the Arctic: when the square kilometers of ice are reduced to less than 1 million square kilometers of sea ice. (The area is considered ice-free at this point and not at zero, because it is very difficult to melt the thick ice around the Canadian Arctic Archipelago, the islands north of the Canadian mainland.)

Why does the amount of ice in the Arctic matter? The Arctic acts as the planet's thermoregulator, helping to cool the planet by reflecting the sun's heat. The Arctic's thermal regulation helps support an atmospheric thermal gradient across latitudes (i.e., decreasing temperature per degree of latitude as one moves towards the poles), moderating our climate. A cold Arctic also maintains the circulation of the global oceanic conveyor belt, including the Atlantic Meridional Overturning Circulation (AMOC). Should the AMOC weaken significantly, it would have multiple and devastating impacts to our weather patterns, fisheries, and marine ecosystems, as a result of reduced heat transfer to deeper ocean waters; colder European winters; more rapid sea level rise; and changes to tropical rainfall (Carrington, 2018).

Here's where the Montreal Protocol comes in. A recent PNAS paper by England and Polvani shows that one effect of the Montreal Protocol--the world's treaty to address the phase-out of ozone-depleting chemicals – has been the delaying of an ice-free event in the Arctic by as much as 10-15 years. Modeling studies showed that without the Montreal protocol, the first ice-free year could have occurred 10-15 years earlier. With the Montreal protocol, current projections are that the ice-free year will be closer to 2050, depending on future emissions. The impact of the Montreal Protocol is entirely the result of reduced greenhouse gas warming due to these regulations on ozone-depleting chemicals, which are also potent greenhouse gases.

Other international treaties will be equally important. For example, nations have begun discussions in an Intergovernmental Negotiating Committee to develop a legally binding instrument on plastic pollution. Plastic's global carbon footprint was estimated to be 1.3 billion metric tons in 2020, roughly 4% of the global carbon budget.And the Global Biodiversity Framework's ambitious 30 by 30 target (conserving 30% of land and ocean areas by 2030), will help protect nature's carbon sinks such as coastal mangroves, seagrasses, and wetlands (known as blue carbon), estimated to remove 3% of the global carbon budget.

The Montreal Protocol has another hopeful lesson for us: that global environmental problems can be solved when nations come together.

P.S. If you'd like to know more about the Arctic and climate change, or better understand the climatic and ecological importance of oceanic circulation, check out our free short courses Arctic Disintegration and the Global Conveyor Belt. Both include great videos by Just Have a Think's Dave Borlace.

P.P.S. We are pleased to share the climate change and sustainability book review list by behavior analyst Dr. Susan Schneider. The author of The Science of Consequences, Dr. Schneider has reviewed 60+ books on climate change and sustainability for you to consider for your own bookshelf.