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fourty years ago, researchers warned that a hole in the layer of ozone bordering the earth could have serious results on human being health and the environment. This trouble is being fixed thanks come a global agreement to prevent the use of ozone-depleting chemicals that damage the ozone layer. But now researchers are involved that the substances provided to replace these ozone-depleting chemicals are acting come trap warmth inside the earth, exacerbating the greenhouse effect. Can policymakers defend the ozone great while also helping stop climate change?
Climate change mitigation menu Data center Subtopics Ozone depleting substances and climate change

Climate change mitigation data center


What is the ozone layer and also how to be it damaged?

The ozone layer sits in the stratosphere between 15 km and also 30 km above the earth. The absorbs many of the sun"s ultraviolet radiation (UV-B), limiting the amount of this radiation the reaches the surface of the Earth. Because this radiation causes skin cancer and cataracts, the ozone layer plays vital role in protecting person health. It likewise prevents radiation damage to plants, animals, and also materials. 

In the 1970s, scientists noticed the the ozone layer to be thinning. Researchers found evidence that linked the depletion the the ozone layer come the visibility of chlorofluorocarbons (CFCs) and also other halogen-source gases in the stratosphere. Ozone-depleting building material (ODS) are synthetic chemicals, which to be used around the civilization in a wide variety of industrial and consumer applications. The main uses of this substances were in refrigeration and also air air conditioning equipment and in fire extinguishers. Other important uses consisted of aerosol propellants, solvents and also blowing agents for insulation foams.


Ozone depletion (blue colours) in the southern hemisphere in 2006.

Source: nationwide Aeronautics and room Administration (NASA) - Goddard room Flight Center 

International activity has been efficient in protecting the ozone layer

To halt the depletion that the ozone layer, countries about the civilization agreed to protect against using ozone-depleting substances. This agreement was formalised in the Vienna Convention for the security of the Ozone great in 1985 and also the Montreal Protocol on building materials that deplete the Ozone great in 1987. In 2009, the Vienna Convention and the Montreal Protocol ended up being the an initial treaties in the background of the United nations to accomplish universal ratification. Substances spanned by the protocol are referred to as "controlled substances". The key substances include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, carbon tetrachloride, methyl chloroform and methyl bromide. The damages to the ozone layer caused by each of these substances is expressed as their ozone depletion potential (ODP). 

Figure 1: usage of controlled ozone-depleting substances

2007, federal governments made second commitment, agreeing to freeze production of HCFCs in developing countries by 2013 and to bring forward the final phase-out day of this chemicals to 2030.

These worldwide agreements assisted to substantially reduce the worldwide use the ozone-depleting substances in Europe and around the human being (Figure 1). Clinical monitoring shows signs that the ozone great is beginning to recover. Full recovery is not expected to occur before the middle of the 21st century.

Protecting the ozone layer likewise protects the climate

The reduction in ozone-depleting substances has additionally had a valuable side-effect. Ozone-depleting substances space also really potent greenhouse gases, contributing come the phenomenon as various other substances widely recognized to have a greenhouse effect like carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). Therefore, by to reduce emissions of ozone-depleting substances, the Montreal Protocol has protected both the ozone layer and the climate at the exact same time.

The magnitude of this advantage is substantial. The palliation in ODS emissions intended as a an outcome of compliance with the Montreal Protocol has been approximated globally in ~ 10-12 giga-tonnes the CO2-equivalent between 1985 and 2010 (Velders et al. 2007). In contrast, the reduction target the greenhouse gas emissions under the Kyoto Protocol (assuming complete compliance by all emerged countries) is estimated at 1-2 giga-tonnes that CO2-equivalent on mean per year between 2008 and 2012, contrasted to base-year emissions. The phasing out of climate-changing ODS under the Montreal Protocol has as such avoided greenhouse gas emissions by an lot 5-6 times bigger than the target of the Kyoto Protocol because that 2008-2012.

ODS substitutes are currently raising comes to

The reduction of ODS emissions is not a uniformly confident story. In fact it has actually indirectly led to brand-new problems. Fluorinated gases (F-gases) have actually been presented as substitutes because that ODS in countless sectors such together refrigeration and also air air conditioning applications. F-gases incorporate hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6). These gases perform not deplete the ozone layer, but they are greenhouse gases. This way that these brand-new gases likewise contribute come climate change. And also to do matters worse, this F-gases regularly have a much larger impact on the climate than "traditional" greenhouse gases such together carbon dioxide (CO2). Because that example, some F-gases have actually a greenhouse impact that is approximately 23 000 times much more powerful 보다 the very same amount the carbon dioxide. Fortunately, the emissions the F-gases are much smaller 보다 those that CO2, but the use of F-gases and also their presence in the environment have increased due to the fact that the 1990s. As a result, the far-ranging contribution that the Montreal Protocol come fighting climate adjust is in peril of gift wiped the end by the farming importance that F-gas emissions.

Global and European agreements to border F-gases

F-gas emissions room monitored under the united Nations framework Convention top top Climate readjust (UNFCCC) and also its Kyoto Protocol, yet not right now addressed by the Montreal Protocol. Fluorinated gases presently account for about 2% of an international greenhouse gas emissions. Several countries have started to take procedures on F-gases, led by the europe Union (EU) which has actually committed to reducing usage of HFCs, the most essential F-gases, by 80% the today"s levels by 2030.

There are two ideologies to reduce F-gas emissions. The first approach is to stop the usage of F-gases completely by using gases or innovations that are much less damaging come the climate. The 2nd approach is to reduce the usage of F-gases in products and equipment. The EU an initial set out certain policies to minimize F-gas emissions in 2006 through the so-called 2006 F-gas Regulation, and with a directive limiting F-gases provided in air air conditioning in cars, the so-called MAC Directive. In the absence of this legislation, F-gas emissions to be projected to boost (Figure 2, orange line).

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 A amendment 2014 F-gas Regulation was embraced in 2014 which will lead to far-reaching additional savings (figure 2, blue line) due greatly to the following new measures:

A progressive “phase-down” the HFCs indigenous 2015 onwards accomplished by step wise limiting the quantities that have the right to be placed on the EU market.A variety of accompanying bans.