|
PROTECTING
EARTH’S OZONE LAYER ALSO HELPED SLOW CLIMATE CHANGE
NOAA March 9, 2007 — An
international agreement to reduce ozone-depleting chemicals, based in part on
science conducted in the 1980s by NOAA scientists and their colleagues, also has
slowed global warming by years, according to a new study by scientists at the
NOAA Earth System Research Lab and their partners. The double effect occurred
because compounds that destroy the atmosphere’s ozone layer also act as
greenhouse gases. The findings will be available in the Proceedings of the
National Academy of Sciences online edition this week.
The ozone layer shields the Earth
from harmful ultraviolet radiation. To protect this layer, nations around the
world signed the Montreal Protocol in 1987 to control the production and use of
ozone-depleting substances.
“Science conducted by NOAA
scientists and their colleagues provided the scientific basis for the framers of
the Montreal Protocol,” said retired Navy Vice Admiral Conrad Lautenbacher,
Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA
administrator. “This is an example of how NOAA’s science informs those who
make decisions that affect our daily lives. This new study also illustrates the
multiplier effect of NOAA’s targeted research and its benefits on multiple
sectors of science.”
While protecting the ozone layer,
the Montreal Protocol also has cut in half the amount of greenhouse warming
caused by ozone-destroying chemicals that would have occurred by 2010 had these
substances continued to build unabated in Earth’s atmosphere, according to the
study. The amount of warming that was avoided is equivalent to 7-12 years of
rise in carbon dioxide concentrations in the atmosphere.
“The participants in the
Montreal Protocol have done something very good for our climate,” says NOAA
Earth System Research Lab scientist David Fahey, one of the authors. “While
addressing ozone depletion, they also provided an early start on slowing climate
change.”
The amount of greenhouse gases
curbed by the Montreal Protocol is equivalent to five times the reduction target
for the first phase of the Kyoto Protocol, a 2005 international agreement to
address climate change, according to the authors. The Kyoto Protocol did not
regulate ozone-depleting chemicals because the prior agreements of the Montreal
Protocol had already dealt with them.
Earlier studies showed that
continued growth in ozone-depleting substances would lead to significant heating
of Earth’s climate. The new analysis quantifies the near-term climate benefits
of controlling these substances.
The paper also explores options
for reducing future use of ozone-depleting substances, such as collecting and
destroying chemical storage banks in old refrigerators and air conditioners,
choosing substitutes with low climate-warming impact and evaluating the
feasibility of further reducing overall emissions of the substances.
The authors also consider the
impact of voluntary chemical restrictions that began in 1975 in some countries.
When these earlier reductions are taken into account, the amount of additional
heating of Earth’s climate that would have occurred by 2010 is far greater
than that avoided since 1987 when the Montreal Protocol went into effect, though
the exact amount of the total benefit is uncertain.
Guus Velders of The Netherlands
Environmental Assessment Agency and Stephen Andersen of the U.S. Environmental
Protection Agency led the study, which appears in the Proceedings of the
National Academy of Sciences. Besides Fahey, other authors are John Daniel, also
of the NOAA Earth System Research Lab and Mack McFarland of DuPont
Fluoroproducts, Wlimington, Del.
Media Contact: Anatta, NOAA
Research
|
