. Solar Energy News .




.
OZONE NEWS
Protecting the climate by reducing fluorinated greenhouse gas emissions
by Staff Writers
Duebendorf, Switzerland (SPX) Feb 28, 2012

They are used as cooling agents in air conditioning plants and refrigerators, as propellants in aerosol cans, as solvents and as foaming agents in the manufacture of foam products. However, there is a downside to the use of HFCs - they are also very potent greenhouse gases. HFC-134a, also known as R-134a, for example, which is used in automobile air conditioning units, is 1430 more active than the classic greenhouse gas carbon dioxide (CO2).

The Montreal Protocol led to a global phase-out of most substances that deplete the ozone layer, such as chlorofluorocarbons (CFCs). A happy side-effect of the gradual ban of these products is that the Earth's climate has also benefited because CFCs are also potent greenhouse gases. However, now a rebound effect threatens to accelerate the rate of global warming.

Hydrofluorocarbons (HFCs), which have been used in recent years in increasing quantities as substitutes for CFCs, are also climatically very active and many are also extremely long-lived. In the renowned journal Science an international team of researchers recommends that the most potent of these gases also be regulated. This could save the positive side effect of the Montreal Protocol for the global climate.

It is regarded as the most successful international environmental agreement and has, to date, been ratified by 196 countries - the Montreal Protocol on Substances That Deplete the Ozone Layer. As a result, CFCs and ozone killers will gradually disappear from the atmosphere over the coming decades. And because many of these substances are also very active greenhouse gases, the Earth's climate will profit from the sinking concentrations too.

So far, so good. In many processes where previously CFCs were used, these are now being increasingly substituted by fluorinated compounds such as HFCs (which, simply put, are similar substances to CFCs but do not contain chlorine and do not deplete stratospheric ozone).

They are used as cooling agents in air conditioning plants and refrigerators, as propellants in aerosol cans, as solvents and as foaming agents in the manufacture of foam products. However, there is a downside to the use of HFCs - they are also very potent greenhouse gases. HFC-134a, also known as R-134a, for example, which is used in automobile air conditioning units, is 1430 more active than the classic greenhouse gas carbon dioxide (CO2).

International environmental agreements can also have unwanted side effects
The reduction of greenhouse gas emissions is covered by the Kyoto Protocol. This agreement is, however, not binding for the world's largest emitter of greenhouse gases, the USA (which has never ratified the protocol), nor for threshold and developing countries.

In addition the Kyoto Protocol is currently limited to the period from 2000 to 2012. No agreement has yet been reached on extending it. What this means is that the significant increase in global emissions of HFCs seen over the past few years will soon negate the positive effects on climate brought by the Montreal protocol's CFC phase-out.

This link is shown by an analysis published in the latest issue of Science. An international team of researchers, headed by Holland's Guus Velders and including the chemistry Nobel laureate Mario Molina and Empa researcher Stefan Reimann, investigated the unintentional (positive) climate effects resulting from the Montreal Protocol.

Since the year 2000 the radiative forcing (a measure of the effect on the climate of chemical substances) of all ozone-depleting substances including CFCs has remained at a more or less constant value of 0.32 W/m2, compared to a value of 1.5 W/m2 for CO2.

Had the Montreal Protocol recommendations not been implemented, today's value would be approximately double this figure, i.e. 0.65 W/m2. Putting things another way, the CFC ban has prevented the equivalent of 10 billion tonnes of CO2 being emitted into the atmosphere in 2010, five times the annual reduction target set by the Kyoto Protocol.

Velders, Reimann and their co-authors fear that this positive effect will soon be negated by HFC emissions, which are currently increasing at 10 to 15% annually. In their article they state that the HFC contribution to climate change can be viewed as an unintended negative side effect of the Montreal Protocol.

At the moment the effect is still small - about 0.012 W/m2 for all CFC substitutes combined. But it is beyond question that radiative forcing due to HFCs will rise significantly in future as a result of increasing demand and production for these substances, above all in threshold and developing countries.

The atmospheric scientists estimate that this value will rise to between 0.25 und 0.4 W/m2 by the year 2050. The greatest problem is presented by saturated HFCs, which are extremely stable and survive in the atmosphere for up to 50 years, exhibiting a long-term global warming potential of up to 4000 times higher than CO2. For Empa researcher Reimann the situation is clear: Long-lived HFCs should no longer be used in these quantities.

Literature: G.J.M. Velders, A.R. Ravishankara, M.K. Miller, M.J. Molina, J. Alcamo, J.S. Daniel, D.W. Fahey, S.A. Montzka, S. Reimann, Preserving Montreal Protocol Climate Benefits by Limiting HFCs, Science (2012), DOI: 10.1126/science.1216414

Related Links
-
All about the Ozone Layer




.
.
Get Our Free Newsletters Via Email
...
Buy Advertising Editorial Enquiries




.

. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle



OZONE NEWS
Ozone Suite on Suomi NPP Continues More Than 30 Years of Ozone Data
Greenbelt, MD (SPX) Feb 27, 2012
A new satellite instrument suite is now sending back detailed information about the health of the Earth's ozone layer, the shield that protects the world's population from harmful levels of the sun's ultraviolet radiation. The Ozone Mapper and Profiler Suite, or OMPS, is one of five new instruments flying aboard NASA's Suomi National Polar-orbiting Partnership satellite (NPP), which was la ... read more


OZONE NEWS
Green fuel versus black gold

Biofuel said a sustainable fuel source

Plant toughness: Key to cracking biofuels?

Maize hybrid looks promising for biofuel

OZONE NEWS
Humanoid Robot Exhibition Opens Drexel Engineers Week

In new mass-production technique, robotic insects spring to life

A robot sketches portraits

New 'soft' motor made from artificial muscles

OZONE NEWS
Yorkshire officials OK Hull turbine plant

Wind farm on hold over bald eagle concerns

Golden eagles found dead at wind farm

Japan firms plan wind farm near Fukushima: report

OZONE NEWS
Cheaper battery power heralds electric car

Mechanism Behind Capacitor's High-Speed Energy Storage Discovered

Daimler, Mercedes seal Aussie G-Wagen deal

Japanese carmakers boost production in January

OZONE NEWS
China urges Khartoum to resolve S. Sudan crisis

Nuclear Iran would 'choke' world economy: Israel PM

BP discussing $14 bn settlement: report

TransCanada in new push for US pipeline

OZONE NEWS
India slap cases on aid groups over nuclear row: reports

India freezes aid group funds over nuclear protests

Study Confirms Low Levels of Fallout from Fukushima and Enhances Knowledge

India PM blames foreign NGOs for anti-nuclear demos

OZONE NEWS
Controller Announces Bill to Drive Private Sector Energy Retrofits

10 Advantages to Supporting Geothermal Energy

Ireland to sell Bord Gais energy business

Obama defends energy policy

OZONE NEWS
Penn researcher helps discover and characterize a 300-million-year-old forest

UN recognizes US Girl Scouts for palm oil effort


Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

.

The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement