Public Release: 14-Aug-2017
American Geophysical Union
WASHINGTON D.C. — The Montreal Protocol, the international treaty adopted to restore Earth’s protective ozone layer in 1989, has significantly reduced emissions of ozone-depleting chemicals from the United States. In a twist, a new study shows the 30-year old treaty has had a major side benefit of reducing climate-altering greenhouse gas emissions from the U.S.
That’s because the ozone-depleting substances controlled by the treaty are also potent greenhouse gases, with heat-trapping abilities up to 10,000 times greater than carbon dioxide over 100 years.
The new study is the first to quantify the impact of the Montreal Protocol on U.S. greenhouse gas emissions with atmospheric observations. The study’s results show that reducing the use of ozone-depleting substances from 2008 to 2014 eliminated the equivalent of 170 million tons of carbon dioxide emissions each year. That’s roughly the equivalent of 50 percent of the reductions achieved by the U.S. for carbon dioxide and other greenhouse gases over the same period. The study was published today in Geophysical Research Letters, a journal of the American Geophysical Union.
“We were surprised by the size of the decline, especially compared with other greenhouse gases,” said Lei Hu, a researcher with the Cooperative Institute for Research in Environmental Sciences (CIRES) working at NOAA and lead author of the new study.
Hu added that the benefits of the Montreal Protocol on greenhouse gas emissions would likely grow in the future. By 2025, she projects that the effect of the Montreal Protocol will be to reduce U.S. greenhouse gas emissions by the equivalent of 500 million tons of carbon dioxide per year compared with 2005 levels. This reduction would be equivalent to about 10 percent of the current U.S. emissions of carbon dioxide.
Previous studies have demonstrated that the Montreal Protocol has been more effective at curtailing global greenhouse gas emissions than any other international effort – even though climate change was not a consideration during the initial treaty negotiations in the late 1980s.
The new analysis, based on data collected by NOAA’s atmospheric monitoring network, confirms that the Montreal Protocol has been highly successful in the U.S. in its primary goal – reducing emissions of manufactured chlorine-based chemicals that, in addition to depleting ozone world-wide, create a hole the size of the continental U.S. in the Earth’s protective ozone layer over the Antarctic each September and October.
Those chemicals–chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), and their substitutes, the hydrofluorocarbons (HFCs)–have been widely used as refrigerants, foam blowing agents, aerosol propellants, fire retardants, and solvents. Chlorine from CFCs was first identified as capable of destroying stratospheric ozone in 1974. The Montreal Protocol has controlled the production and consumption of these chemicals since the late 1980s.
Implementation of the Montreal Protocol in the United States, largely through the Clean Air Act, led to a near complete phase-out of U.S. production and consumption of chlorofluorocarbons (CFCs) beginning in 1996 and a 95 percent decline of hydrochlorofluorocarbons (HCFCs) production since 1998.
As a result, total emissions of CFCs in the U.S. have decreased by two-thirds from 2008 to 2014, while emissions of HCFCs declined by about half, the study authors said.
Another indication of the treaty’s impact is increasing U.S. emissions of ozone-friendly chemicals, such as hydrofluorocarbons or HFCs. However, some HFCs are also potent greenhouse gases, and their increased use is offsetting some of the climate benefit of the Montreal Protocol, said Stephen Montzka, a researcher at NOAA and co-author of the new study.
Countries adhering to the Protocol, including the U.S., agreed to limit future production and consumption of HFCs in 2016.
“This shows what can be achieved by concerted and thoughtful international effort,” said Scott Lehman of the Institute of Arctic and Alpine Research at the University of Colorado Boulder and co-author of the new study. “Hopefully, the Protocol can serve as a model of the international cooperation that we need to tackle the real problem – carbon dioxide.”
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This research article is open access for 30 days. A PDF copy of the article can be downloaded at the following link: http://onlinelibrary.wiley.com/doi/10.1002/2017GL074388/pdf.
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Title: “Considerable Contribution of the Montreal Protocol to Declining Greenhouse Gas Emissions from the United States”
Authors: Lei Hu, Colm Sweeney, Debra J. Mondeel, David Nance: Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder and NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, U.S.A.;
Stephen A. Montzka, Arlyn E. Andrews, Kirk Thoning, John B. Miller, James W. Elkins, Bradley D. Hall, Pieter P. Tans: NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, U.S.A.;
Scott J. Lehman: Institute of Arctic and Alpine Research, University of Colorado-Boulder, Boulder, Colorado, U.S.A.;
David S. Godwin: Stratospheric Protection Division, Office of Atmospheric Programs, Office of Air and Radiation, U.S. Environmental Protection Agency, Washington, District of Columbia, U.S.A.;
Benjamin R. Miller: Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, NOAA Earth System Research Laboratory, Global Monitoring Division and Institute of Arctic and Alpine Research, University of Colorado-Boulder, Boulder, Colorado, U.S.A.;
Caroline Siso: Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, NOAA Earth System Research Laboratory, Global Monitoring Division, Boulder, Colorado, U.S.A. and Stratospheric Protection Division, Office of Atmospheric Programs, Office of Air and Radiation, U.S. Environmental Protection Agency, Washington, District of Columbia, U.S.A.;
Thomas Nehrkorn, Marikate Mountain: Atmospheric and Environmental Research, Lexington, Massaschusetts, U.S.A.;
Marc L. Fischer: Environmental Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, California, U.S.A.;
Sébastien C. Biraud: Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, California, U.S.A.;
Huilin Chen: Cooperative Institute for Research in Environmental Sciences, University of Colorado-Boulder, Boulder, Colorado, U.S.A. and Centre for Isotope Research, University of Groningen, Groningen, The Netherlands.
Contact information for the authors: Lei Hu: +1 (303) 497-5238, lei.hu@noaa.gov
AGU Press Contact:
Lauren Lipuma
+1 (202) 777-7396
NOAA Press Contact:
Theo Stein
+1 (303) 497-6288
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From what little I’ve read, the whole ozone depletion scare remains controversial.
The reason it was easy to implement the treaty and emissions was because all that was required was to substitute one chemical refridgerant for another at the factories. No requirement to exchange all of the R12 in vehicles already on the road or in existing refridgerators and freezers. It didn’t cost any govt much, if any, money to pass the laws and in general the manufacturers had no particular reason to object to the refridgerant switch. AC units didn’t work as efficiently using the new stuff, which offset some of its advantages with respect to emissions,as cars burned more gasoline to cool the vehicle.
I seriously doubt the figures claimed here – the people writing this are enthusiastic true believers, and therefore completely biased and apt to see benefits where few exist –
Once upon a time I asked this hypothetical question of my staff, who at the time were researching a environmental issue that had never been studied before. How did we know there was NOT a hole in the ozone layer over the Antarctica before people began staying there or before we put a satellite up? Both basically happened since the middle of the 20th Century. At the other end, what is the first thing a Indian villager buys when his village gets reliable electricity and he saves enough money? A refrigerator! Just like carbon dioxide emissions it is doubtful that India will reduce its output of “older” refrigerants anytime soon.
Trivia: Why do people often sneeze when they look towards bright sun? UV solar radiation converts oxygen to ozone which is highly reactive and irritating to the nasal lining. This causes sneezing. So back to the explanations about solar UV and ozone – low solar UV in winter along with low atmospheric temperature and high level cloud leads to reduced ozone, which we are supposed to be afraid of because the ozone is supposed to protect us from the solar UV… except that the ozone is low exactly when and where the UV is low. Another example of a natural self regulated system that we should just be appreciative of, rather than trying to change the climate/atmosphere through human rituals.
It is an interesting idea that has been mentioned re: the Montreal Protocol /Ozone Hole scare being a dry run for Global Warming. If this were true – does it give us any pointers as to how the current scare might end?
““This shows what can be achieved by concerted and thoughtful international effort,” said Scott Lehman of the Institute of Arctic and Alpine Research at the University of Colorado Boulder and co-author of the new study. “Hopefully, the Protocol can serve as a model of the international cooperation that we need to tackle the real problem – carbon dioxide.”
Yeah, but controlling CFC’s didn’t cost us hundreds of billions of dollars and blight the landscape with windmills like eliminating CO2 would do. Besides, there is no evidence that CO2 in the atmosphere is harmful.