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The greenhouse effect has been described, by the US Vice President Al Gore, as the potentially most dangerous environmental problem facing mankind, with consequences second only to nuclear war.
The greenhouse effect can be visualized as follows: Imagine that Earth has been encircled by a giant glass sphere. The heat of the sun penetrates through the glass. Some of the heat is absorbed by the Earth, and some of it is radiated back towards space. The radiated heat reaches the glass sphere and is prevented from dispersing any further.
Similarly, the earth is surrounded by a blanket of gases. This blanket traps energy in the atmosphere, much the same way as glass traps heat inside a greenhouse. This results in an accumulation of energy, and the overall warming of the atmosphere. The 'greenhouse effect' is the popular expression for the above process.
Global warming and climate change result from the greenhouse effect. The consequences of global warming and climate change could well include:
the eradication of entire ecosystems
increased frequency and intensity of storms, hurricanes,
floods and droughts
melting glaciers and polar ice
rising sea levels resulting in the permanent
flooding of vast areas of heavily
populated lands and the creation of hundreds of millions of environmental refugees
increased frequency of forest fires
spread of tropical diseases due to insect proliferation 
An introduction to the science of man-made climate change.
An introduction to the climate system.
Climate change and desertification.
Will there be growing numbers of environmental migrants ?
The special concerns of coastal areas and small island states.
The possible health effects of climate change.
Societies under stress from climate change.
2. WHAT WILL CLIMATE CHANGE LEAD TO?
Climate models show that atmospheric temperatures will increase by between 1.5 and 4.5 C by the year 2100 if a "wait and see and do nothing" approach is adopted. The global temperature increase since the last ice age (10,000 years ago) has been about 5 C.
This may not sound like much, but such drastic temperature rise would be unprecedented for modern civilization, both in terms of its intensity and its rate of increase. It is projected to have drastic social, economic and ecological implications of unpredictable dimensions:
Because of thermal expansion of the water and melting of continental glaciers
sea levels would rise, possibly as much as two feet (0.6 metres), by the end of
next century.
Rising temperatures could lead to changes in regional wind systems which would
influence global rainfall distribution and lead to the redistribution and
frequency of floods, droughts and forest fires. Windstorms and hurricanes could
become more frequent and more intense.
Increased sea temperatures would cause coral bleaching and the destruction of
coral reefs around the world.
Climate change would create favorable conditions for growth in insect
populations. This would likely have a negative effect on agriculture and human
health, and result in a spread of malaria and other tropical diseases.
Water supplies would become disrupted in some regions, particularly in already
vulnerable, arid areas.
Natural climate variability vs. man-made climate change.
Will climate change lead to more extremes and disasters?
Societies under stress
Climate change and desertification.
Climate change and sea-level rise.
The impact of climate change on water resources.
The possible health effects of climate change.
The impact of climate change on agriculture.
Climate and food security.
3. DOES THE GREENHOUSE EFFECT OCCUR NATURALLY?
Yes, it does. The greenhouse effect is a natural process which made life on Earth possible. Without naturally occurring greenhouse gases such as water vapour, carbon dioxide, methane and nitrous oxide, the Earth's surface temperature would be 33 degrees Celsius cooler - a chilly -18 C rather than the tolerable 15 C.
However, since the beginning of industrialization, 200 years ago, concentrations of these gases have increased substantially . It is estimated that the Earth's average temperature has risen by 0.5 to 0.6 degrees C since 1880 because of emissions of greenhouse gases from human activity.
The main sources of these emissions--particularly carbon dioxide, methane and nitrous oxide --are the combustion of large amounts of fossil fuels in the energy and transport sectors, deforestation and the use of intensive farming methods.
When we talk about the greenhouse effect we mean the ENHANCED effect which is caused by the increase of greenhouse gases from human sources.
The role of greenhouse gases.
Why climate change and global warming are not the same.
Energy and greenhouse gas emissions.
Fuel and the carbon cycle.
How extracting and transporting fossil fuel releases greenhouse gases.
Global energy use during the Industrial Age.
4. WHAT IS THE DIFFERENCE BETWEEN THE GREENHOUSE EFFECT, GLOBAL WARMING AND CLIMATE CHANGE?
These terms are often used to describe the same problem, but actually relate to cause and effect, or problem and consequence. The greenhouse effect is the cause - and global warming and climate change are the consequences.
The greenhouse effect causes an accumulation of heat (or energy) in the Earth's atmosphere. The global climate must then adjust to deal with that extra accumulation of energy, and these adjustments result in global warming and climate changes.
Global warming results from an increase in the temperature of the Earth's lower atmosphere. Climate changes result from alterations to regional climatic events such as rainfall patterns, evaporation and cloud formation.
Why climate change and global warming are not the same.
Natural climate variability vs. man-made climate change.
An introduction to the climate system.
5. WHAT CAUSES THE GREENHOUSE EFFECT?
The greenhouse effect is caused by gases in the atmosphere which have the ability to absorb the sun's energy that is usually radiated back into space from Earth. Energy from the sun comes into the earth as short-wave radiation; some is absorbed and some is radiated back as long-wave radiation. The 'greenhouse gases' allow the short-wave radiation to pass through to Earth but absorb the long-wave radiation that is reflected back to space. These gases include naturally occurring gases - primarily water vapour, carbon dioxide, methane, nitrous oxides - as well as industrial chemicals such as chlorofluorocarbons (CFCs).
The problem is that human activities have increased the atmospheric concentration of these gases well beyond their natural levels, and have introduced new greenhouse gases, such as CFCs. This in turn is throwing the natural climatic systems off balance.
One of the major greenhouse gases from human sources is carbon dioxide (CO2). While CO2 is naturally occurring, its concentration in the atmosphere is rapidly increasing because of the burning of the fossil fuels- oil, coal and gas.
Human activity is not only producing more CO2, but is also severely damaging the ability of the earth to absorb carbon - via its carbon sinks - the forests and oceanic plankton. Growing forests absorb CO2. Massive worldwide forest destruction results in much fewer trees to soak up CO2, and releases the stored CO2 from the trees into the atmosphere.
Similarly, the destruction of the ozone layer by human-made chemicals, such as CFCs, is allowing increased levels of harmful UV-B radiation to reach the surface of the earth. Increased levels of UV-B radiation could reduce the density of plankton in the oceans. Since plankton are the primary carbon sink of the planet, reduction in their density could result in less CO2 being absorbed from the atmosphere.
Damage to the planet's carbon sinks, through deforestation and ozone layer depletion, thus makes a direct contribution to the enhanced greenhouse effect.
The role of greenhouse gases.
Radiation, climate and climate change.
CO2 emissions and the "missing carbon" problem.
Oceans and the carbon cycle.
Chlorofluorocarbons (CFCs) and climate change.
6. HOW CAN RELATIVELY LITTLE CO2 EMITTED BY HUMANS MAKE A DIFFERENCE ?
There is an important difference between the CO2 produced by nature and that emitted by human activities. While nature produces about 30 times more CO2 than human activity, the carbon emitted by nature is part of a finely balanced cycle. The emissions by humans are over and above the natural balance, and consequently result in a net increase in the concentrations of atmospheric CO2.
Since the industrial revolution about 850 billion tonnes of CO2 have been emitted due to combustion of fossil fuels, oil, coal and natural gas. An additional 370 billion tonnes have been added through changes in land use and deforestation.
Every year humans emit around 25 billion tonnes of CO2 into the atmosphere, which equals approximately 48,000 tonnes every minute.
Some estimates show that a reservoir of 37, 000 billion tonnes of CO2 is buried in the ground as oil, coal and gas. The largest portion of this CO2 reservoir is in coal, and the second largest is in natural gas. This is a chilling reminder of what is in store for the planet, should we decide to continue to burn fossil fuels without any restrictions. Experts estimate that emission of 2,500 billion tonnes of CO2 - a mere 7% of the existing stock of fossil fuels - will result in a doubling of pre-industrial concentrations of CO2.
CO2 emissions and the "missing carbon" problem.
Global energy use during the Industrial Age.
Natural climate variability vs. man-made climate change.
7. HOW DO WE KNOW THE GREENHOUSE EFFECT IS A REALITY?
We know that the greenhouse effect is really happening through a number of sources:
First, the fact that some gases have the ability of trapping heat is based on
simple physics. No credible scientist questions this fact.
Second, measurements since the mid-fifties have shown that the levels of
greenhouse gases in the atmosphere are steadily increasing , and that these
increases correspond to industrial emissions of greenhouse gases.
Third, measurements of air trapped in 250, 000 year old ice cores show that: (a)
the concentration of greenhouse gases in the atmosphere have varied in the past
and these variations have occurred concurrently with temperature changes; and (b)
greenhouse gases have been increasing since pre-industrial times.
The role of greenhouse gases.
How records from the past climates support the case for global warming.
Global energy use during the Industrial Age.
Natural climate variability vs. man-made climate change.
8. WHAT DO THE EXPERTS CONCLUDE ABOUT CLIMATE CHANGE?
In 1988, the United Nations Environment Programme (UNEP) and the World Meteorological Organization WMO established the Intergovernmental Panel on Climate Change (IPCC), consisting of more than 300 of the world's leading experts, to investigate climate change.
The IPCC concluded, both in 1990 and in 1992, that a doubling of greenhouse gases in the atmosphere will lead to "serious consequences for the world's social, economic and natural systems".
Among other things, the IPCC concluded that emissions of greenhouse gases from human activities contributes to the natural greenhouse effect and will lead to an additional warming of the atmosphere. The IPCC estimated that a doubling of CO2 would lead to a global warming of 1.5 to 4.5 degrees C.
The Intergovernmental Panel on Climate Change (IPCC)
The Convention on Climate Change: What does it say?
9. GLOBAL WARMING AND CLIMATE CHANGE? IS THERE STILL A DEBATE?
In most scientific circles the issue is no longer whether or not climate change is a potentially serious problem, but rather, how the problem will develop, what its effects will be, how these can be best detected, and what measures can be taken to reduce the damage.
The media, at times, leaves the impression that scientists are still discussing whether or not the climate is really changing as a result of emissions of greenhouse gases. This is not the case. In actuality there is a broad agreement on this issue among scientists and experts, as represented by the Intergovernmental Panel on Climate Change (IPCC).
No scientific material has ever been presented in scientific fora which challenges the main conclusions of the IPCC, in spite of the fact that the IPCC has an open process that invites critical views.
Why climate change and global warming are not the same.
The Intergovernmental Panel on Climate Change (IPCC)
Why IPCC assessment reports are objective.
10. WHEN WILL WE KNOW IF THE GREENHOUSE EFFECT IS HAPPENING?
The Intergovernmental Panel on Climate Change (IPCC) stated in its 1990 report that "the unequivocal detection of the enhanced greenhouse effect from observations is not likely for a decade or more". However, recent events are leading to an reassessment of that statement by many scientists. Increasing number of scientists are declaring that the recently observed global warming trend is not natural and is likely to be linked to the greenhouse effect.
There are many worrying indicators that something serious is happening:
The nine hottest years on record have all occurred since 1980, despite the 2-3
year cooling effect of the Mount Pinatubo volcanic eruption in 1991. 1994 was the
third or fourth hottest year on record.
Since the mid-19th. Century global temperatures have increased by around 0.5 C.
Temperatures have increased in all seasons in the Southern Hemisphere, and in
spring, winter and autumn in the Northern Hemisphere.
The European summer of 1994 brought temperatures up to 6 C above average, which
induced massive fires in Southern Europe, chronic air pollution problems across
the continent, and severe water shortages in many cities.
Scientists at the Max-Planck Institute For Meteorology in Hamburg concluded from
a recent examination of recent temperature records that they are 90 - 97.5
percent certain that the observed warming of the last 20-30 years is not due to
natural variability.
A study of global mean temperatures over 1000 years prompted Princeton
University researchers to recently state, "...these results suggest that the
observed trend is not a natural feature of the interaction between the atmosphere
and oceans. Instead, it may have been induced by a sustained change in the
thermal forcing, such as that resulting from changes in atmospheric greenhouse
gas concentrations and aerosol loading."
According to scientists, the retreat of glaciers and the warming of the tundra
permafrost is clear evidence of climatic change. Currently, there is a pronounced
loss of ice mass and mountain glacier retreat occurring all over the world.
Alpine plants are migrating upwards in the Austrian and Swiss Alps in response
to warming temperatures, migratory birds are confused, trees and small animals
are migrating Northward in Canada, marine organisms are migrating northward in
California, all in response to warming air or sea temperatures.
In May 1994, the British Antarctic Survey reported the fastest sustained
atmospheric warming on the Antarctic Peninsula, since reliable worldwide
temperature observations began 130 years ago. A startling 2.5 C warming in
Antarctica has been reported since 1940. Linked with that warming has been the
disintegration of Antarctic ice-sheets; the recent unforeseen calving of a giant
iceberg, the size of Cyprus (78km long and 37km wide); the decline of adelie
penguin populations; and the blooming of plants.
The medical journal the Lancet reported in January 1994 that increased
temperatures in Pakistan since 1878 have extended the period suitable for the
development of the malarial parasite. Paul Epstein, of the Harvard School of
Public Health, considers that climate change may be liberating pests and
pathogens from ecological controls and predation. He cites as an example that
mosquitoes which transmit yellow and dengue fever were formerly restricted to
less than 1000 metres in altitude by temperature, but are now reported at 2, 200
metres in India and Colombia.
In January of 1995, Europe was devastated by
yet another "hundred year" flood,
its second in 15 months. The floods caused the evacuation of 250,000 people in
Holland, and cost billions of US dollars in damages.
According to Dutch climate
expert Pier Vellinga, though the floods were no proof of climate change, they
were consistent with global circulation models (GCMs) and with current CO2
concentrations. He said, "I would be surprised if something like this did not
happen."
Is the Earth warming up yet?
Will climate change lead to more extremes and disasters?
Insurance against climate change?
11. HOW CAN WE PREDICT CLIMATE CHANGE WHEN WE CAN 'T EVEN PREDICT THE WEATHER ?
It is important to understand the difference between climate and weather. Climate, essentially means 'average weather'.
While the details of weather, in a particular region, are hard to predict from week to week, weather patterns over years, that is the climate, are easier to identify, understand and predict. The overall system - the climate - is predictable, even though the details - the day to day weather - are much less certain.
For example, while it may be nearly impossible to predict, two months in advance, what the weather will be like on a given Saturday in Paris, if the month in question is July, most climate models can correctly predict that it won't snow.
Natural climate variability vs. man-made climate change.
Why three hot summers don't mean global warming?
Are climate models reliable?
12. WILL ALL THE IMPACTS OF THE GREENHOUSE EFFECT BE NEGATIVE?
The effects of global warming and climate change will not impact the same way upon every region in the world, or upon all species of life. For example, a slight temperature increase in some of the colder parts of the world may create less hostile conditions for human habitation and improve conditions for agriculture. Similarly, changing rainfall patterns may favour some species over others.
However, favourable consequences of the greenhouse effect for some regions or species does not mitigate its overall negative global impacts. The social, economic and ecological disruptions brought about by climatic changes worldwide are projected to greatly outweigh regional benefits.
The impacts of global warming and climate change could become a source of increased tension between nations and regions .
While the developed, industrialized world is responsible for 75% of all CO2 emissions, these impacts will most likely hit hardest upon the poorer, underdeveloped parts of the world.
For example, as sea levels rise countries like Bangladesh and Micronesia will suffer much more from the loss of valuable arable and populated lands, then European or North American countries, even though in comparison, they will have emitted only a tiny fraction of the greenhouse gases.
The effect of drowning coastlines could lead to hundreds of millions of climate refugees. Where will these refugees go? How will they be cared for? Undoubtedly, such a catastrophe will seriously exacerbate the already critical refugee problem in the world.
A severe disruption of the world's food supplies through floods, droughts, crop failures and diseases brought about by climate change would trigger famines, wars and civil disorder in many countries.
Most human societies - especially subsistence agricultural societies - have evolved over many centuries by adapting to their present climatic conditions. Their agriculture, technologies, economies and culture are based on familiar circumstances. These societies are likely to find climate change, on the scale and speed predicted for the coming decades, to be very traumatic.
Similarly, many natural ecosystems will not be able to adjust fast enough to a rapidly warming world. This could lead to sharp increases in the already alarming rate of species extinction on the planet.
A survey of possible social impacts.
The issue of winners and losers.
Climate change and North-South relations.
Why the poor are most vulnerable.
Societies under stress.
The possible cultural and psychological impacts.
Will there be growing numbers of environmental migrants?
The special concerns of developing countries.
The special concerns of coastal areas and small island states.
Climate and food security.
The impact of climate change on agriculture.
13. WHAT MUST BE DONE TO REDUCE HUMAN CONTRIBUTIONS TO THE GREENHOUSE EFFECT?
The bottom line is that the emissions of greenhouse gases must be reduced. We must develop industrial practices and means of transportation which are less dependent on fossil fuels, and ultimately, manage completely without them.
Since the problem is global, the solutions must be international. The international community took a first step in 1992 when the Framework Convention on Climate Change was signed by 167 countries in Rio. The Framework Convention morally committed industrialized countries to stabilizing their emissions of CO2 by the year 2000 at 1990 levels. However, since the 1990 levels of global CO2 emissions enhanced the greenhouse effect, the 1992 agreement is obviously inadequate.
Unfortunately, few, if any, of the industrialized countries will even meet this weak target. Consequently, the next step must be to make this commitment legally binding, and to strengthen it through a CO2 Reduction Protocol aimed at meeting the objectives of the Convention. The minimum goal must be a 20% reduction in CO2 emissions by 2005, based on 1990 levels.
The industrialized countries have the lion's share of the responsibility for creating the problem and for finding the solutions. They have developed their industrial base, and consequently, their higher standards of living, through the use of vast amounts of fossil fuels. This has resulted in high concentrations of CO2 in the atmosphere.
Furthermore, their per capita emissions of CO2 continues to be tens of times larger than all of the developing countries.
For example, the United States, the largest single emitter, annually pumps into the atmosphere approximately 20 tonnes of CO2 per person. With less then 5% of the world's population, the United States is responsible for 25% of global CO2 emissions. In a comparison, the entire developing world, consisting of more than 100 countries and representing almost 80% of the world's population, is responsible for approximately the same amount of CO2 emissions.
The Intergovernmental Panel on Climate Change (IPCC).
The Convention on Climate Change: What does it say?
A 'responsibility index' for climate change.
Climate change and North-South relations.
Will the North-South gap widen?
Why the poor are most vulnerable.
14. CAN THE WORLD SURVIVE WITHOUT FOSSIL FUELS? WHAT ARE THE ALTERNATIVES?
It is becoming apparent that the world may not be able to survive with fossil fuels. This means that we must develop renewable sources of energy which are environmentally sustainable. Fortunately, we already posses the technology at hand to provide clean and reliable sources of energy for meeting human needs.
Renewable systems include solar photo voltaic power systems, solar hot water systems, wind turbines, bio-fuel plantations, hydroelectric systems and so on. These energy sources are sustainable because they never 'run out'.
Most importantly, many renewable energy sources, such as wind power and solar thermal, are already cheaper than conventional fuels-- even though the price of fossil fuels and nuclear power does not reflect their full environmental and economic costs.
Many of these renewable energy options can be designed, built, and exploited locally and at less costs than conventional systems. They contribute significantly to national economies because they exploit indigenous labour and materials.
In rural areas, the most sophisticated solar arrays can provide sufficient high-quality energy, at a cost lower than power from electricity grids. Solar power could radically improve the living conditions of the world's poorest people. Fortunately, the technology is spreading:
200,000 solar photo voltaic systems have been installed around the world,
including 37,000 in Mexico, 20,000 in Kenya, 16,000 in Indonesia, 15,000 in
China, 4,500 in Sri Lanka, 4,000 in the Dominican Republic and 1,000 in Brazil.
In Kenya more rural households obtain their electricity from solar energy than
from the official policy of grid extension.
In the Dominican Republic, Enersol, a US-based non-governmental organization,
has successfully trained local entrepreneurs to assemble, market, install and
service photo voltaic systems. The program began in 1985 with 6 systems, grew to
a 100 in 1987, more than 1,000 in 1989 and 4,500 in 1994. Since 1992, Enersol has
replicated their successful Dominican program in Honduras and Guatemala and
contributed to projects in Bolivia and Costa Rica. The Solar Electric Light Fund
(SELF) has taken the Enersol model and has established a number of successful
'solar seed' projects around the world.
The European Commission's 'Power for the World Program' (a global photo voltaic action plan) estimates that providing solar electricity to a billion people in the developing world would cost $60 billion ($3 billion a year for 20 years). This is only 3% of annual energy investments in developing countries and less than 0.5% of current military expenditure.
Similar solar solutions are also available for industrial applications to supply reliable grid connected electricity. In the United States, as part of a plan to develop a 1,000 MW Solar Enterprise Zone in the Nevada desert, ENRON has announced plans to build a 100 MW solar power station. Such a power station would be the largest solar operation in the United States, producing enough power for a city of 100,000 people.
The world needs a revolution in the use of renewable energy technologies.
The case for reducing emissions despite scientific uncertainty.
Reducing greenhouse gas emissions from the energy sector.
The economic benefits of cutting greenhouse gas emissions.
15. WHAT CAN I DO ABOUT THE GREENHOUSE EFFECT?
Here are some of practical steps that you can take to reduce human contributions to the greenhouse effect.
LEARN about the greenhouse effect, global warming and climate change.
Learn about alternate, non-fossil fuel based energy sources. Inform your family,
friends and colleagues.
WRITE to your local newspapers and other media outlets and demand they
regularly feature stories regarding global warming, climate change and the
greenhouse effect. The media has the responsibility to inform the public about
this urgent subject.
DEMAND your government fulfills your country's commitments to
stabilizing emissions of CO2 by the year 2000 at 1990 levels, and makes further
commitments to a 20% reduction in CO2 emissions by 2005, based on 1990 levels.
TAKE responsibility for making simple changes in your energy
consumption. The main greenhouse gas, CO2, comes from the burning of fossil
fuels. Two key areas where individuals can help reduce the emissions of CO2 are
in electricity consumption and transportation. Coal and gas-fired power plants
burn huge amounts of fossil fuels and consequently emit vast amounts of CO2. A
car produces more than its own weight in carbon dioxide each year, roughly 2
tonnes per year.
Save Electricity:
SUPPORT the development of renewable energy technologies.
DEMAND your government aims to achieve a minimum 3% per year penetration of your
country's energy supply system with renewable technologies.
Reducing greenhouse gas emissions from the energy sector.
16. WHAT IS GREENPEACE DOING ABOUT THE GREENHOUSE EFFECT AND CLIMATE CHANGE?
The Greenpeace International Climate Campaign aims to: (a) inform the public about the seriousness of climate change and global warming; (b) create the political climate that will compel governments to take immediate and effective action; and (c) promote environmentally sustainable solutions for generating and conserving energy to meet human needs.
Greenpeace maintains that: (a) only through public pressure will the politicians be motivated to deal with this problem in a truly responsible manner; (b) since the causes and the impacts of climate change are global, the solutions must also be based on international agreements. Consequently, the Greenpeace Climate Campaign is both national and international.
The Greenpeace campaign aims to influence national governments to institute domestic policies that substantially reduce greenhouse gas emissions, and to support the development of environmentally sustainable options, such as renewable energy generation. The campaign also intervenes in the international arena, for example at the United Nations Framework Convention on Climate Change, to push the world community towards deep cuts in global CO2 emissions.
Greenpeace demands that, at the minimum, CO2 reductions in industrialized countries must be reduced by 20% of 1990 levels, by the year 2005 through a legally binding CO2 Reduction Protocol.
The Greenpeace Climate Campaign is solutions oriented. Greenpeace is working to
shift global energy dependence from environmentally dangerous sources of energy,
such as fossil fuels and nuclear energy, to ecologically sustainable solar energy.
Return to the ABCs of the Climate Crisis