Medicine

Ecology as a science and learning subject, objectives, main environmental laws

Ecology as a science and learning subject, objectives, main environmental laws. The history of ecology. The environment. Global environmental problems.

Ecology is the scientific study of the processes influencing the distribution and abundance of organisms, the interactions among organisms, and the interactions between organisms and the transformation and flux of energy and matter.

Ecology (from Greek: οἶκος, "house"; -λογία, "study of") is the scientific study of the relations that living organisms have with respect to each other and their natural environment

The environment encompasses the whole of life on earth and the complex interactions that link the living world with the physical world. In a general sense, this covers everything contained within the air, land and water. Sudden and dramatic natural changes to the environment have occurred, and continue to occur, which have the potential to upset the whole balance of the Earth's ecosystem. Significant environmental issues cause impacts throughout the world.

• The environment encompasses the whole of life on earth and the complex interactions that link the living world with the physical world

• In a general sense, this covers everything contained within the air, land and water

• Time also is a key factor as historic issues have an influence on the status of the environment - locally and globally, both now and in the future

GLOBAL WARMING

Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. According to the 2007 Fourth Assessment Report by the Intergovernmental Panel on Climate Change (IPCC), global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the 20th century. Most of the observed temperature increase since the middle of the 20th century has been caused by increasing concentrations of greenhouse gases, which result from human activity such as the burning of fossil fuel and deforestation. Global dimming, a result of increasing concentrations of atmospheric aerosols that block sunlight from reaching the surface, has partially countered the effects of warming induced by greenhouse gases.

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century. The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts.^[4] Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain. As a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.

The scientific consensus is that anthropogenic global warming is occurring. Nevertheless, political and public debate continues. The Kyoto Protocol is aimed at stabilizing greenhouse gas concentration to prevent a "dangerous anthropogenic interference". As of November 2009, 187 states had signed and ratified the protocol.

Proposed responses to climate change include mitigation to reduce emissions, adaptation to the effects of global warming, and geoengineering to remove greenhouse gases from the atmosphere or block incoming sunlight.

Global warming is one environmental issue which needs no introduction - after all it has been in the news for all the good and bad reasons over the last year or so. What needs an introduction though, is the impact that it will have on mankind. Global warming effects on humans have always been downplayed, perhaps because most of them are based on climatic models which the critics allege are too crude to rely on. However, critical evaluation of the evidence of global warming - such as climate change pattern and rising frequency of hurricanes, is more than enough for a person to understand the ground reality. It's another thing that we are too engrossed to sit back and ponder over the most obvious global warming causes and effects.

EFFECTS OF GLOBAL WARMING ON HUMANS

In what can be best described as domino effect on the Earth's environment, one thing will lead to another as a result of global warming - and in matter of time several species will be completely wiped off from the planet. When we talk about species, it includes humans as well. Even though we don't face the direct threat of extinction, quite a few effects of global warming on the environment will affect us directly or indirectly. Given below are the details of some global warming effects on humans which will help you picture the situation.

What we refer to as the effects and consequences of global warming will start with melting of polar ice as well as glaciers due to excessive rise in global near-surface temperature. The water from melting glaciers and polar ice will drain into the ocean, which will eventually trigger a sea level rise. More importantly, water tends to expand when heated - and when ocean water will be heated as a result of global warming it will naturally expand and contribute to sea level rise. Rising sea will encroach on land - and low lying areas as well as tiny islands will start submerging. That will turn out to be disastrous, considering that a significant portion of the world population resides in coastal areas which are threatened by encroaching sea.

Melting Glaciers, Drying Rivers: Severe Water and Food Crisis

Coming back to melting glaciers, they are our only reservoirs of potable water and if they melt - which is already happening at an alarming rate, there will be no water to drink. Some of the major rivers of the world originate in these glaciers, and melting of glaciers as a result of global warming will sound the death knell for these rivers. At the end of the day, we will end up facing a severe water crisis - and the prophecy about we having the World War III for water will come true. Other than using river water for drinking, we are also dependent on it for agriculture. If there are no rivers, it is bound to affect the agriculture sector and result in food shortage for us. Similarly, all this occurrences will disturb the water cycle, hamper the normal pattern of precipitation and trigger environmental issues - such as droughts, on the planet. Sooner or later, most of the regions on the planet will become barren and we won't have land to cultivate. End result - no water to drink, no food to eat courtesy global warming.

Warm Climate: Spread of Diseases

As far as global warming effects on human health are concerned, they may be far more severe than we can possibly imagine. One of the most obvious global warming effects on Earth will be the change in climatic conditions of different regions. If the planet becomes warm, it will become a heaven for disease spreading insects. These insects - which cannot survive in cold regions beyond the tropics now, will begin to flourish in these regions which will then have conducive environment for them. As they start spreading out, they will also spread diseases attributed to them which will affect more people and result in more casualties.
If global warming effects on animals and plants were not convincing enough, these global warming effects on humans are bound to come as an eyeopener for all those people who thought global warming was a myth. At the end of the day, we need to understand that we are a part of the ecosystem, and any thing which threatens the ecosystem is a threat for us either directly or indirectly. It's high time we stop taking this environmental issue so lightly and implement global warming solutions to reduce its impact. Now that there is ample evidence that global warming and deforestation, burning of fossil fuels, use of CFCs, etc., are related to each other, we can go ahead and restrict this hazard by keeping a check on these anthropogenic activities. If we don't act now, the loss will be too much and revival may turn out to be impossible.

Climate change and what do people believe

Recent polls suggest that most people still believe that climate change is real thing. For instance according to the poll carried out by British Guardian 83% of people in Britain believe that climate change is current/imminent threat.
However, just believing in climate change is obviously not enough to change things for better. So many talks about climate change on global level, and still no sign of the new international climate deal.That's pretty funny because if so many people believe in climate change then why isn't there much bigger public pressure on world leaders to do something about it, and why are failures on agreeing the new climate deal so easily accepted by the worldwide media?

Does the world really care so little about our planet, or are we just too naive by thinking that if we remain ignorant about climate change issue everything will work out for the best in the end? Surprisingly so, even the most world leaders believe in climate change (well at least they say how they believe) but they still delay the necessary decisions for "better times". What better times? Do we really have to wait for disaster to happen before actually doing something, and is really our industry so important that we could gamble with the future of our planet and the future of our children and grandchildren? Politicians are not be trusted, they say one thing during the elections, and then after the election all of the sudden a memory loss, and they delay the necessary decisions because "now is not the right time to act on this matter". Of course it isn't because powerful industrial lobbies say it so, and politics as always listens them blindly in to everything they have to say.
Our beliefs are so weakened by the power of money that we find it hard to see what's good and what's bad, and climate change is obvious proof to this.
What will our children and grandchildren think about us if we fail to act on climate change? What kind of legacy are we leaving to them? And for what? A few dollars more?

What is Global Warming and Climate Change?

Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in “greenhouse” gases such as Carbon Dioxide (CO₂).

A warming planet thus leads to a change in climate which can affect weather in various ways, as discussed further below.

What are the main indicators of Climate Change?

As explained by the US agency, the National Oceanic and Atmospheric Administration (NOAA), there are 7 indicators that would be expected to increase in a warming world (and they are), and 3 indicators would be expected to decrease (and they are):

What is the Greenhouse Effect?

The term greenhouse is used in conjunction with the phenomenon known as the greenhouse effect.

Energy from the sun drives the earth’s weather and climate, and heats the earth’s surface;
In turn, the earth radiates energy back into space;
Some atmospheric gases (water vapor, carbon dioxide, and other gases) trap some of the outgoing energy, retaining heat somewhat like the glass panels of a greenhouse;
These gases are therefore known as greenhouse gases;
The greenhouse effect is the rise in temperature on Earth as certain gases in the atmosphere trap energy.

Image source: Greenhouse Effect, Wikipedia(Link includes detailed explanation of the above image). Note, image above expresses energy exchanges in watts per square meter (W/m²)

Six main greenhouse gases are carbon dioxide (CO₂), methane (CH₄) (which is 20 times as potent a greenhouse gas as carbon dioxide) and nitrous oxide (N₂O), plus three fluorinated industrial gases: hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF₆). Water vapor is also considered a greenhouse gas.

The Greenhouse effect is natural. What do we have to do with it?

Many of these greenhouse gases are actually life-enabling, for without them, heat would escape back into space and the Earth’s average temperature would be a lot colder.

However, if the greenhouse effect becomes stronger, then more heat gets trapped than needed, and the Earth might become less habitable for humans, plants and animals.

Carbon dioxide, though not the most potent of greenhouse gases, is the most significant one. Human activity has caused an imbalance in the natural cycle of the greenhouse effect and related processes. NASA’s Earth Observatory is worth quoting the effect human activity is having on the natural carbon cycle, for example:

In addition to the natural fluxes of carbon through the Earth system, anthropogenic (human) activities, particularly fossil fuel burning and deforestation, are also releasing carbon dioxide into the atmosphere.

When we mine coal and extract oil from the Earth’s crust, and then burn these fossil fuels for transportation, heating, cooking, electricity, and manufacturing, we are effectively moving carbon more rapidly into the atmosphere than is being removed naturally through the sedimentation of carbon, ultimately causing atmospheric carbon dioxide concentrations to increase.

Also, by clearing forests to support agriculture, we are transferring carbon from living biomass into the atmosphere (dry wood is about 50 percent carbon).

The result is that humans are adding ever-increasing amounts of extra carbon dioxide into the atmosphere. Because of this, atmospheric carbon dioxide concentrations are higher today than they have been over the last half-million years or longer.

— The Carbon Cycle; The Human Role,

Another way of looking at this is with a simple analogy: consider salt and human health:

A small amount of salt is essential for human life;
Slightly more salt in our diet often makes food tastier;
Too much salt can be harmful to our health.

In a similar way, greenhouse gases are essential for our planet; the planet may be able to deal with slightly increased levels of such gases, but too much will affect the health of the whole planet.

The other difference between the natural carbon cycle and human-induced climate change is that the latter is rapid. This means that ecosystems have less chance of adapting to the changes that will result and so the effects felt will be worse and more dramatic it things continue along the current trajectory.

The climate has always varied in the past. How is this any different?

Throughout Earth’s history the climate has varied, sometimes considerably. Past warming does not automatically mean that today’s warming is therefore also natural. Recent warming, has been shown to be due to human industrialization processes.

John Cook, writing the popular Skeptical Science blog summarizes the key indicators of a human finger print on climate change:

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO₂ has increased since the Industrial Revolution:

(Source: NOAA) via: Climate Change: How do we know? NASA, accessed October 27, 2009

The above covers hundreds of thousands of years and shows how atmospheric CO₂ levels have dramatically increased in recent years. If we “zoom” in on just the past 250 years, we see the following:

Global CO₂ emissions, 1751–2007, Carbon Dioxide Information Analysis Center (CDIAC), August 2010,DOI:10.3334/CDIAC/00001_V2010

NASA’s Goddard Institute of Space Studies (GISS) tracks atmospheric global temperature climate trends. As environmental engineer, D Kelly O’Day, writes on ProcessingTrends.com explains: “To facilitate assessments of long term trends, climatologists compare the mean for a base period with the annual mean. Differences between the annual mean and baseline mean are called anomalies. GISS uses the 1951 - 1980 period for their baseline period. They use the difference between the annual mean and the baseline mean to determine the global temperature anomaly for the year.”

O’Day produced a chart showing global temperature anomalies between 1800 and 2006 using data from NASA. I updated the chart he provided to include recently updated data up to 2010:

Sources: GISS Surface Temperature Analysis, NASA, accessed January 30, 2011; Global temperature, 1800-2006, ProcessTrends.com, accessed October 27, 2009

In the 1880 - 1935 period, the temperature anomaly was consistently negative. In contrast, the since 1980 the anomaly has been consistently positive. The 1917 temperature anomaly (-0.47oC) was the lowest year on record. Since 1917, global temperature has warmed, with the most recent years showing the highest anomalies of +0.6 oC in the past 120 years.

or many years, large, influential businesses and governments have been against the idea of global warming. Many have poured a lot of resources into discrediting what has generally been accepted for a long time as real.

Now, the mainstream is generally worried about climate change impacts and the discourse seems to have shifted accordingly. Some businesses that once engaged in disinformation campaigns have even changed their opinions, some even requesting governments for regulation and direction on this issue.

However, a few influential companies and organizations are still attempting to undermine climate change action and concerns. Will all this mean a different type of spin and propaganda with attempts at green washing and misleading information becoming the norm, or will there now be major shift in attitudes to see concrete solutions being proposed and implemented?

Climate Justice and Equity

For a number of years, there have been concerns that climate change negotiations will essentially ignore a key principle of climate change negotiation frameworks: the common but differentiated responsibilities.

This recognizes that historically:

Industrialized nations have emitted far more greenhouse gas emissions (even if some developing nations are only now increasing theirs);
Rich countries therefore face the biggest responsibility and burden for action to address climate change; and
Rich countries therefore must support developing nations adapt—through financing and technology transfer, for example.

This notion of climate justice is typically ignored by many rich nations and their mainstream media, making it easy to blame China, India and other developing countries for failures in climate change mitigation negotiations.

Development expert, Martin Khor, calculated that taking historical emissions into account, the rich countries owe a carbon debt because they have already used more than their fair quota of emissions.

Yet, by 2050 when certain emission reductions are needed by, their reduced emissions will still add up to be go over their fair share:

However, rather than continue down the path of unequal development, industrialized nations can help pay off their carbon debt by truly helping emerging countries develop along a cleaner path, such as through the promised-but-barely-delivered technology transfer, finance, and capacity building.

So far however, rich nations have done very little within the Kyoto protocol to reduce emissions by any meaningful amount, while they are all for negotiating a follow on treaty that brings more pressure to developing countries to agree to emissions targets.

In effect, the more there will be delay the more the poor nations will have to save the Earth with their sacrifices (and if it works, as history shows, the rich and powerful will find a way to rewrite history to claim they were the ones that saved the planet).

These issues are explored in more depth here.

ACID RAIN .

Acid rain is a rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxides which react with the water molecules in the atmosphere to produce acids. Governments have made efforts since the 1970s to reduce the release of sulfur dioxide into the atmosphere with positive results. Nitrogen oxides can also be produced naturally by lightning strikes and sulfur dioxide is produced by volcanic eruptions.

"Acid rain" is a popular term referring to the deposition of wet (rain, snow, sleet, fog, cloudwater, and dew) and dry (acidifying particles and gases) acidic components. A more accurate term is “acid deposition”. Distilled water, once carbon dioxide is removed, has a neutral pH of 7. Liquids with a pH less than 7 are acidic, and those with a pH greater than 7 are alkaline. “Clean” or unpolluted rain has a slightly acidic pH of over 5.7, because carbon dioxide and water in the air react together to form carbonic acid, but unpolluted rain also contains other chemicals.^[1]

H₂O (l) + C O₂ (g) H₂C O₃ (aq)

Carbonic acid then can ionize in water forming low concentrations of hydronium and carbonate ions:

H₂O (l) + H₂C O₃ (aq) H C O₃⁻ (aq) + H₃O⁺ (aq)

Acid deposition as an environmental issue would include additional acids to H₂C O₃.

Human activity

The principal cause of acid rain is sulfur and nitrogen compounds from human sources, such as electricity generation, factories, and motor vehicles. Coal power plants are one of the most polluting. The gases can be carried hundreds of kilometers in the atmosphere before they are converted to acids and deposited. In the past, factories had short funnels to let out smoke but this caused many problems locally; thus, factories now have taller smoke funnels. However, dispersal from these taller stacks causes pollutants to be carried farther, causing widespread ecological damage. Also, livestock production plays a major role. It is responsible for almost two-thirds of all anthropogenic sources of ammonia produced through human activities, which contributes significantly to acid rain.

Chemical processes

Combustion of fuels creates sulfur dioxide and nitric oxides. They are converted into sulfuric acid and nitric acid.

Gas phase chemistry

In the gas phase sulfur dioxide is oxidized by reaction with the hydroxyl radical via an intermolecular reaction:^[

SO₂ + OH· → HOSO₂·

which is followed by:

HOSO₂· + O₂ → HO₂· + SO₃

In the presence of water, sulfur trioxide (SO₃) is converted rapidly to sulfuric acid:

SO₃ (g) + H₂O (l) → H₂SO₄ (l)

Nitrogen dioxide reacts with OH to form nitric acid:

NO₂ + OH· → HNO₃

Chemistry in cloud droplets

When clouds are present, the loss rate of SO₂ is faster than can be explained by gas phase chemistry alone. This is due to reactions in the liquid water droplets.

Hydrolysis

Sulfur dioxide dissolves in water and then, like carbon dioxide, hydrolyses in a series of equilibrium reactions:

SO₂ (g) + H₂O SO₂·H₂O

SO₂·H₂O H⁺ + HSO₃⁻

HSO₃⁻ H⁺ + SO₃²⁻

Oxidation

There are a large number of aqueous reactions that oxidize sulfur from S(IV) to S(VI), leading to the formation of sulfuric acid. The most important oxidation reactions are with ozone, hydrogen peroxide and oxygen (reactions with oxygen are catalyzed by iron and manganese in the cloud droplets).

Acid deposition

Wet deposition

Wet deposition of acids occurs when any form of precipitation (rain, snow, etc.) removes acids from the atmosphere and delivers it to the Earth's surface. This can result from the deposition of acids produced in the raindrops (see aqueous phase chemistry above) or by the precipitation removing the acids either in clouds or below clouds. Wet removal of both gases and aerosols are both of importance for wet deposition.

Dry deposition

Acid deposition also occurs via dry deposition in the absence of precipitation. This can be responsible for as much as 20 to 60% of total acid deposition. This occurs when particles and gases stick to the ground, plants or other surfaces.

Adverse effects

This chart shows that not all fish, shellfish, or the insects that they eat can tolerate the same amount of acid; for example, frogs can tolerate water that is more acidic (i.e., has a lower pH) than trout.

Acid rain has been shown to have adverse impacts on forests, freshwaters and soils, killing insect and aquatic life-forms as well as causing damage to buildings and having impacts on human health.

Surface waters and aquatic animals

Both the lower pH and higher aluminium concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill adult fish. As lakes and rivers become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United StatesHowever, the extent to which acid rain contributes directly or indirectly via runoff from the catchment to lake and river acidity (i.e., depending on characteristics of the surrounding watershed) is variable. The United States Environmental Protection Agency's (EPA) website states: "Of the lakes and streams surveyed, acid rain caused acidity in 75 percent of the acidic lakes and about 50 percent of the acidic streams".

Soils

Soil biology and chemistry can be seriously damaged by acid rain. Some microbes are unable to tolerate changes to low pHs and are killed. The enzymes of these microbes are denatured (changed in shape so they no longer function) by the acid. The hydronium ions of acid rain also mobilize toxins such as aluminium, and leach away essential nutrients and minerals such as magnesium.

2 H⁺ (aq) + Mg²⁺ (clay) 2 H⁺ (clay) + Mg²⁺ (aq)

Soil chemistry can be dramatically changed when base cations, such as calcium and magnesium, are leached by acid rain thereby affecting sensitive species, such as sugar maple (Acer saccharum).

Forests and other vegetation

Effect of acid rain on a forest, Jizera Mountains, Czech Republic

Adverse effects may be indirectly related to acid rain, like the acid's effects on soil (see above) or high concentration of gaseous precursors to acid rain. High altitude forests are especially vulnerable as they are often surrounded by clouds and fog which are more acidic than rain.

Other plants can also be damaged by acid rain, but the effect on food crops is minimized by the application of lime and fertilizers to replace lost nutrients. In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands. When calcium is leached from the needles of red spruce, these trees become less cold tolerant and exhibit winter injury and even death.

Human health

Scientists have suggested direct links to human health.

Other adverse effects

Effect of acid rain on statues

Acid rain can also damage buildings and historic monuments, especially those made of rocks such as limestone and marble containing large amounts of calcium carbonate. Acids in the rain react with the calcium compounds in the stones to create gypsum, which then flakes off.

CaCO₃ (s) + H₂SO₄ (aq) CaSO₄ (aq) + CO₂ (g) + H₂O (l)

The effects of this are commonly seen on old gravestones, where acid rain can cause the inscriptions to become completely illegible. Acid rain also increases the oxidation rate of metals, in particular copper and bronze.

Affected areas

Places with significant impact by acid rain around the globe include most of eastern Europe from Poland northward into Scandinavia,the eastern third of the United States, and southeastern Canada. Other affected areas include the southeastern coast of China and Taiwan.

CAUSES OF OZONE DEPLETION

The cause of ozone depletion is the increase in the level of free radicals such as hydroxyl radicals, nitric oxide radicals and atomic chlorine and bromine. The most important compound, which accounts for almost 80% of the total depletion of ozone in the stratosphere are chlorofluorocarbons (CFC). These compounds are very stable in the lower atmosphere of the Earth, but in the stratosphere, they break down to release a free chlorine atom due to ultraviolet radiation. A free chlorine atom reacts with an ozone molecule (O3) and forms chlorine monoxide (ClO) and a molecule of oxygen. Now chlorine monoxide reacts with an ozone molecule to form a chlorine atom and two molecules of oxygen. The free chlorine molecule again reacts with ozone to form chlorine monoxide. The process continues and the result is the reduction or depletion of ozone in the stratosphere.

Possible Effects of Ozone Depletion

If you are wondering why is the ozone layer important, then the answer lies in the harmful effects of ultraviolet rays. The ozone layer is responsible for absorbing the ultraviolet rays and thereby preventing them from passing through the atmosphere of Earth. Ultraviolet rays of the Sun are associated with a number of health related and environmental issues. The most important of these is the association between ultraviolet rays and an increased risk of developing several types of skin cancers including malignant melanoma, basal and squamous cell carcinoma. Even the incidents of cortical cataracts can also increase significantly with the increased exposure to ultraviolet rays.

Another observation in this regard is that a decrease in the ozone in the stratosphere can lead to an increase in the ozone present in the lower atmosphere. Ozone present in the lower atmosphere is mainly regarded as a pollutant and a green house gas that can contribute to global warming and climate change. However, researches have pointed out that the lifespan of atmospheric ozone is quiet less as compared to stratospheric ozone. At the same time, increase in the surface level of ozone can enhance the ability of sunlight to synthesize vitamin D, which can be regarded as an important beneficial effect of ozone layer depletion.

The effects of ozone depletion are not limited to humans only, as it can affect animals and plants as well. It can affect important food crops like rice by adversely affecting cyanobacteria, which helps them absorb and utilize nitrogen properly. Phytoplankton, an important component of the marine food chain, can also be affected by ozone depletion. Studies in this regard have shown that ultraviolet rays can influence the survival rates of these microscopic organisms by affecting their orientation and mobility.

The increasing concern for the causes and effects of ozone depletion led to the adoption of the Montreal Protocol, in the year 1987, in order to reduce and control the industrial emission of chlorofluorocarbons. International agreements have succeeded to a great extent in reducing the emission of these compounds, however, more cooperation and understanding among all the countries of the world is required to mitigate the problem.

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