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Climate Change, CO2 and Carbon
[top]
[end]Global
warming and climate change
Global warming has always taken place; without it, the planet would
be freezing cold and uninhabitable. It is caused by sunlight, which
radiates to the earth as short wave radiation, being trapped by the
'greenhouse gases' surrounding the earth. As the solar radiation
reaches the earth and the atmosphere around it (the troposphere),
that part of the radiation which is converted to infra-red
radiation can no longer pass through these gases so freely and is
locked into the atmosphere. To try to return to an equilibrium, the
air heats up until the outgoing long-wave radiation (OLR) matches
the incoming solar radiation. Currently, this steady state is not
being reached and the planet is gradually becoming hotter - known
as the
Enhanced Greenhouse Effect
Radiative forcing describes the changes brought about by the
mechanism described above. A positive radiative forcing makes the
earth and the atmosphere around it hotter (global warming), whilst
a negative radiative forcing makes it cooler.
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[end]2.
Trends and History
[top]
[end]Greenhouse
gases and aerosols
Greenhouse gases can be split into those that are
naturally occurring, and those that are produced as a result of
human activity. Important greenhouse gases include
carbon dioxide, ozone,
methane,
nitrous oxide and water vapour. Over the last
thirty or so years, there has been a steady and unprecedented climb
in the levels of greenhouse gases, and most people now believe that
this accelerated growth is largely man-made (anthropogenic). This
increase in greenhouse gases is raising the temperature of the
earth and the air around it to dangerous levels. Manufacturing,
power generation, farming and transport are largely blamed, and the
excessive level of greenhouse gases they produce are believed to be
at the root of climate change.
See a country list of Carbon Dioxide emissions per
capita here
Aerosols (microscopic airborne particles or droplets) affect global
warming. Some of them (such as those from erupting volcanoes) have
a cooling effect. Most aerosols will scatter and absorb solar and
infrared radiation in the atmosphere, and have probably had an
overall negative contribution to global warming. They also affect
cloud formations by increasing the numbers of fine particles that
retain the droplets in warm clouds.
On the other hand, black carbon (soot), created by burning
carbonaceous fuels, tend to warm the planet. The quantity of black
carbon is a function of the way in which it is burnt, and recent
research indicates that the smoke from household cooking stoves is
particularly high in black carbon.
'Positive feedbacks' involving water vapour, snow, and ice may
amplify the direct response to greenhouse gas emissions by a factor
of two to three. The water vapour feedback is particularly
important as water vapour is a powerful greenhouse gas, and models
project that global warming will raise water vapour levels in the
lower atmosphere - a phenomenon that appears to be happening
already, particularly in the Northern hemisphere. Water vapour
concentrations are affected by temperature and pressure, which
dictate how much vapour can be carried within the atmosphere. If
water vapour is at an altitude where the temperature is lower than
ground temperature it will inhibit outgoing radiation, causing
positive forcing. As the difference in these two temperatures
widens, the effect is exacerbated. Further, as the air warms,
allowing more water vapour to be held, this increases the effect,
and is known as positive water vapour feedback.
Snow and ice reflect sunlight very effectively. If a small warming
melts snow earlier in the year, more energy will be absorbed by the
ground exposed underneath it, in turn causing more warming. This is
the main reason wintertime northern regions are expected to warm
the most.
Clouds are closely connected with this system; although they may
prevent infrared radiation from escaping, they also reflect back
some of the solar radiation. As clouds form from water vapour, they
release latent heat, which can be a central influence in a weather
system (
http://www.grida.no/climate/ipcc_tar/wg1/266.htm).
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[end]3.
Current Best Practice
HEDON Household Energy Network has created a
special interest group called
CarbonSIG where through this, people who are
concerned and working on climate change issues are trying to create
a sustainable environment that benefits those living in poverty
through information, discussion and action around improved
household energy.
Authors / contributers wanted! Do you have knowledge or
expertise in this topic? If you do, please consider writing
something for this topic...
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[end]4.
Areas of Research
[top]
[end]Cooking
and greenhouse gases
Over two billion people cook using
biomass, and yet more cook one coal - the
majority of whom cook over three-stone fires and / or rudimentary
stoves. These cooking methods lead to substantial levels of
Products of Incomplete Combustion (PICs) - over one hundred of
them, among which are some of the more potent greenhouse gases,
including methane and Nitrous oxide . The amount of global warming
attributed to each gas is known as its Global Warming Potential
(GWP), which describes its potential relative to
carbon dioxide. As gases break down over
different periods of time, GWP changes with the time period over
which the global warming is being considered - known as the Time
Horizon.
Table 1 shows some of the more common greenhouse gases, modified
from the IPCC working group report 2001, showing the GWP with a
time horizon of 100years: (
http://www.grida.no/climate/ipcc_tar/wg1/130.htm#tab41a)
| Chemical species | Formula | 100-yr GWP |
| Carbon dioxide | CO2 | 1 |
| Methane | CH4 (ppb) | 23 |
| Nitrous oxide | N2O (ppb) | 296 |
Note, however, that black carbon does not appear in these tables
despite its high global warming potential. For further information
on black carbon see:
[top]
[end]Effects
of global warming
There is a growing consensus that, with a business-as-usual
scenario, the mean global temperature will increase by between 2C
and 5C before the end of this century. We are already seeing the
impacts:
- A rise in the level of the oceans - already driving
island-dwellers from their homes
- The permafrost at the ice-caps disappearing
- More violent and unpredictable weather - hurricanes, flash
floods
- An increase in droughts and violent rains
- Biodiversity reduction as living things fail to evolve fast
enough to survive
- Increase in disease and epidemics as disease vectors spread
geographically
- Parts of the world becoming unbearably hot, leading to mass
migrations, and land and water conflicts
Just to maintain the status quo of levels of carbon dioxide and
other greenhouse gases affecting our planet, we need to reduce
emissions by around 70%.
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[end]5.
Organisations/People
[top]
[end]International
action
Since 1994, most countries of the world have joined an
international treaty -- the United Nations Framework Convention on
Climate Change (
http://unfccc.int/2860.php ) to consider what can be
done to reduce global warming and to cope with whatever temperature
increases are inevitable. The Convention on Climate Change sets an
overall framework for intergovernmental efforts to tackle the
challenge posed by climate change. Under the Convention,
governments strive to:
- Gather and share information on emissions, policies and best
practice
- Launch national strategies for addressing emissions and
adapting to expected impacts. These include provision of financial
and technological support to developing countries
- Cooperate in preparing for adaptation to the impacts of climate
change
An addition to the treaty, the Kyoto Protocol, has more powerful
(and legally binding) measures. Not all countries - notably the US
- have signed up to this Treaty to date.
Main actors at international level
- The Conference of the Parties (COP) is the prime authority of
the Convention. It is an association of all member countries (or
"Parties") and usually meets annually for a period of two weeks.
These sessions are attended by several thousand government
delegates, observer organizations, and journalists.
- The Subsidiary Body for Scientific and Technological Advice
(SBSTA) counsels the Conference of the Parties on matters of
climate, the environment, technology, and method.
- A Subsidiary Body for Implementation (SBI) helps review how the
Convention is being applied. It also deals with financial and
administrative matters.
Expert groups
- The Consultative Group of Experts (CGE) on National
Communications from "non-Annex 1 Parties" helps developing
countries prepare national reports on climate change issues.
- The Least Developed Country Expert Group (LEG)advises such
nations on establishing programmes for adapting to climate
change.
- The Expert Group on Technology Transfer (EGTT) encourages the
sharing of technology with less-advanced nations.
Partner agencies include
- The Global Environment Facility (GEF),
which has existed since 1991 to fund projects in developing
countries that will have global environmental benefits.
- The Intergovernmental Panel on Climate Change (IPCC) provides
services to the Convention; publishing comprehensive reviews every
five years of the status of climate change and climate-change
science, along with special reports and technical papers
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[end]6.
Resources and web links
[top]
[end]HEDON
Cooking and Carbon Special Interest Group
Carbon SIG is a
special interest group on cooking and carbon
being established to discuss all things dealing with all things to
do with climate change and household energy. Its specifically aims
are to connect people and organisations working on household energy
and carbon emission reduction, sequestration and adaptation to
climate change, to support high quality business, government and
NGO networking, to foster co-ordination and collaboration leading
to the creation of new knowledge and ultimately improved household
energy provision and finally to support information exchange on
carbon emission reduction, carbon sequestration, and climate
adaptation in the household energy sector. Carbon SIG special
interest group has its own vocabulary for making the various
meanings of words for climate change and household energy precise
and comprehensive to people that do not have specific knowledge on
this field. You can see the CarbonSIG glossary
here?
[top]
[end]Climate
change science
The IPCC website on climate change (
http://www.grida.no/climate/ipcc_tar/wg1/index.htm)
provides a very comprehensive scientific background to the current
situation. It looks at evidence based on temperature of both land
and sea, humidity, clouds, rainfall, snow and ice cover - and
analyses the likely effects of global warming for separate
geographic areas. The summary for policymakers provides an
excellent overview
http://www.grida.no/climate/ipcc_tar/wg1/005.htm)
Carbon trading - or carbon emissions trading - is a concept where
companies in the industrial world can agree to offset some of their
emissions by paying for those emissions to be reduced in a
developing country. There is substantial argument over whether
these emission reductions are 'real' or whether this mechanism
allows large industrial organisations to continue to pollute by
giving them a 'conscience clause' in that their payment is used to
fund development in other countries. Emissions are sold by price
per tonne of carbon dioxide saved. There are two distinct
mechanisms:
- Clean
Development Mechanism (CDM); This is the mechanism set up under
the Kyoto protocol and is more relevant for very large projects as
verification is expensive and complex. In terms of stoves, there
are currently obstacles to using the CDM as biomass fuel
has to be shown to be 'renewable' both before and after projects
have taken place. This constraint is currently under review by the
COP. Kyoto carbon trading is set to start in April 2007. A detailed
description of how cooking stoves relate to the CDM can be found
here
- Voluntary market: This mechanism is perhaps more appropriate
for smaller projects. Companies (represented by several of our
CarbonSIG members) negotiate with organisations and industries to
provide funding for development projects which reduce carbon
emissions. The level of monitoring and verification differ from
company to company, and are also dependent on the wishes of the
industry offsetting the carbon.
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[end]7.
Documents and further reading
These resources have been taken from the
Carbon SIG special interest group page
edit this page