Significant Cuts in
Carbon Dioxide Along With Cuts in Black
Carbon and Other Greenhouse Gases Offer
Big Boost for Climate, Crops and Human Health
Geneva/Nairobi,
4 September 2009 - Faster action on climate
change may be possible if nations combine
substantial cuts of carbon dioxide emissions
alongside accelerated moves across a suite
of other greenhouse gases and pollutants.
Scientists estimate
that nearly 50 per cent of the emissions
causing global warming in the 21st century
are from non-CO2 pollutants ranging from
black carbon and low-level ozone to methane
and nitrogen compounds.
These 'climate forcers'
will add to the warming caused by carbon
dioxide from the burning of fossil fuels
that have been building up since the Industrial
Revolution unless their emissions are also
addressed.
Many of these non CO2
gases and pollutants need to be addressed
in their own right because of growing concern
over their impact on human health, agriculture
and ecosystems such as forests.
Achim Steiner, UN Under-Secretary-General
and Executive Director of the UN Environment
Programme, pointed out that the time has
come for further urgent scientific assessments
to determine the precise contribution, impacts
and the options for action on 'non-CO2'
pollutants.
"There remains
some scientific uncertainty about some of
these pollutants' precise contribution to
global warming. But a growing body of science
points to a potentially significant role,"
he said.
"The international
community's over-arching concern must be
to seal a convincing deal at the UN climate
convention meeting in Copenhagen in less
than 100 days time-one that puts the world
on track towards swift and significant cuts
in carbon dioxide while also providing the
funding to assist vulnerable countries and
communities to adapt," said Mr. Steiner,
speaking on the margins of the 3rd World
Climate Conference, hosted by the World
Meteorological Organisation.
"It is clear that
the world must deploy all available means
to combat climate change. At this critical
juncture, every transformative measure and
every substance contributing to climate
change should not be overlooked," he
added.
Drew Shindell, a leading
climatologist with NASA's Goddard Institute
for Space Studies, and a lecturer in the
Department of Earth and Environmental Sciences
at Columbia University New York, said: "By
including black carbon and tropospheric
ozone precursors in climate mitigation strategies,
alongside the longer-lived greenhouse gases,
development strategies that are both more
effective and less costly can be developed".
"The UN Environment
Program should be congratulated for raising
these issues and calling for action. The
science supporting the strong role of these
pollutants in climate change and in damage
to human and ecosystem health is becoming
increasingly strong," added the scientist
who has also been a reviewer of the assessments
of the Intergovernmental Panel on Climate
Change (IPCC) and whose science has been
used extensively by the panel.
Experts say that in
addition their climate contribution, there
are compelling and abundant economic and
environmental reasons why some of the non-CO2
pollutants need to be addressed under treaties
such as the UN Framework Convention on Climate
Change and its Kyoto Protocol, the Montreal
Protocol on Substances that Deplete the
Ozone Layer, and regional health agreements,
national air quality strategies and voluntary
initiatives.
Mr Steiner cited black
carbon from the inefficient burning of biomass
and dung for cooking and from diesel engines
and coal-fired power stations. Other major
sources include the burning of forests,
savannas and crop residues.
Black carbon is among
a suite of air pollutants linked to 1.6
million to 1.8 million premature deaths
annually as a result of indoor exposure
and 800,000 as a result of outdoor exposure.
Researchers have also
put a wide range of figures on black carbon's
likely near-term climate change contribution,
ranging from 20 plus per cent to up to 50
per cent of the CO2 warming effects. Especially
damaging are the black carbon emissions
that end up on snow and ice, including the
Arctic and Himalayan Tibetan Plateau.
Tropospheric ozone including
near-surface ozone is a major greenhouse
gas, harms human health and is linked to
significant damage to crops and ecosystems.
A regional assessment
report by the UNEP Project Atmospheric Brown
Cloud cited annual losses from the wheat,
rice, corn and soya bean crop in China,
Japan and the Republic of Korea alone-linked
with ground level ozone-may be $5 billion
a year.
Another study by the
Massachusetts Institute of Technology estimates
that five per cent of cereal production
in the United States is lost to ground level
ozone and that by 2100 crop yields globally
could be cut by 40 per cent.
Up to a fifth of all
summer-time hospital visits in the north-eastern
United States related to respiratory problems
are linked to low level ozone, sometimes
referred to as smog.
Researchers at the University
of Illinois are suggesting that tree growth
in the United States is some seven per cent
less and that this will climb to up to 17
per cent less by 2100 as a result of low
level ozone pollution.
Tropospheric ozone,
which occurs from the ground up to 15 kilometres
in altitude, is generated by substances
such as carbon monoxide and nitrogen oxides
mixing with emissions of petroleum products
like volatile organic compounds and solvents
in the presence of sunlight.
Researchers estimate
that the contribution of tropospheric ozone
to the greenhouse effect could range from
15 per cent to 20 per cent, of the CO2 warming.
Meanwhile nitrogen compounds,
emitted from sources including animal wastes,
sewage, inefficient use of fertilizers,
sewage and vehicle emissions are being linked
to a wide range of impacts and not just
climate change.
The rising number of
dead zones-deoxygenated areas of seas and
oceans-is raising concern over already vulnerable
and depleted fish stocks. Meanwhile nitrogen
compound emissions are also contributing
to changes in vegetation and ecosystems
as a result of their artificial fertilizing
effect.
Mr Steiner, speaking
less than 100 days before the crucial UN
climate convention meeting in Copenhagen,
said: "While carbon dioxide can remain
in the atmosphere for centuries, some of
these other pollutants such as black carbon
and ozone have relatively short-lives in
terms of days, weeks, months or years".
"Fast action across
a broad front could thus deliver some quick
wins on health, food security and wider
environmental concerns while also making
important contributions to advancing the
climate change challenge and the achievement
of the poverty-related Millennium Development
Goals".
Lessons from the Ozone
Layer Treaty
Action under the Montreal
Protocol on Substances that Deplete the
Ozone Layer to phase-out fluorinated gases
such chlorofluorocarbons (CFCs)-substances
once common in products such as hairsprays
and refrigerators-has underlined the multiple
benefits that can occur in a transition
to a Green Economy.
CFCs, whose full and
final global phase-out along with 95 other
chemicals is scheduled for 2010, were identified
as the prime culprit behind the destruction
of the Earth's ozone layer-the high-flying
protective gassy shield that filters out
deadly ultra-violet rays.
In the past few years
scientists have also calculated that the
phase-out will, between 11000 and 2010,
have reduced global emissions by the equivalent
of 135 Gigatonnes of CO2, delaying climate
forcing by up to 12 years.
Governments in 2007
agreed to an accelerated freeze and phase-out
of CFC replacements-hydrochloroflurocarbons
(HCFCs)-specifically for the climate benefits.
Scientists with the
Montreal Protocol estimate that this strategy
could deliver cumulative emission reductions
equal to more than 16 Gigatonnes of CO2
from now up to 2040
Concern is now focusing
on another group of fluorinated gases called
hydroflurocarbons (HFCs) and finding alternatives
to these so they do not now become the replacements
for the replacements.
While HFCs do not damage
the ozone layer, they are significant greenhouse
gases. Under one scenario, they could equal
around 45 per cent of total CO2 emissions
by 2050.
The UN Framework Convention
on Climate Change and the Montreal Protocol
are now cooperating to map out the best
strategy to meet this challenge.
"The story of the
Montreal Protocol underlines how action
on one front can deliver benefits on many
others-that every dollar spent on phasing-out
substances that are damaging the ozone layer
and sparing humanity impacts such as increased
skin cancer and eye cataract cases, has
also been working to address global warming,"
said Mr Steiner.
Background
Black carbon
What is it?
This is basically the smoke that comes out
of diesel vehicles and biomass burning.
It is a pollutant often linked to inefficient
burning, its sources ranging from biomass
burning (including wood and dung in cooking)
to diesel engines and coal-fired power stations.
Unlike CO2, which can
remain in the atmosphere for centuries to
millennia, black carbon has a life of few
weeks or less
One study estimates
that emissions from transport are responsible
for 18.5 per cent of black carbon emissions.
26 per cent of emissions
are from stoves for heating and cooking
with over 40 per cent of this from wood
burning; over 20 per cent from coal; 19
per cent from crop residues and 10 per cent
from dung.
Another estimates that
0.1 per cent of black carbon is from power
stations. Coal for other industrial uses
such as coking may contribute around eight
per cent.
What is it doing?
Black carbon is a key
component of air pollution.
The World Health Organization estimates
that 1.6 million people a year die from
indoor air pollution, making it the 8th
most important risk factor.
In India it may be responsible
for an estimated 3.5 per cent of the disease
burden and in African countries such as
Mali, Malawi and Rwanda, the figure rises
to five per cent.
An additional 800,000
premature deaths are caused each year by
urban air pollution with black carbon and
tropospheric ozone key components.
Climate Change Links
Research indicates that
black carbon in the atmosphere absorbs heat.
The UNEP Atmospheric
Brown Cloud (ABC) project, led by Professor
Ramanathan of the Scripps Institution of
Oceanography in La Jolla, California, suggests
that these brown clouds-which include black
carbon-are playing a major role in the observed
retreat of the glaciers in the Hindu Kush-Himalayan-Tobetan
region.
In addition the ABC
study suggests that solar heating of the
atmosphere by black carbon and dimming at
the surface by black carbon and other pollutant
particles are altering weather patterns
in Asia, including:
Triggering significant
drying in northern China and increased risk
of flooding in southern China and an overall
decrease in monsoon precipitation over India
and Southeast Asia by between five and seven
per cent since the 1950s.
Since the 1950s the
Indian summer monsoon is not only weakening
but shrinking with a decrease in early and
late season rainfall and a decline in the
number of rainy days.
Decreased reflection
of solar radiation by snow and ice due to
increasing deposits of black carbon is emerging
as another major contributor to the melting
of ice and snow.
The precise contribution
to climate change is subject to a great
deal of investigation and, as with all the
non-CO2 pollutants, the role of other substances
and the historical contribution to climate
change is different from the contribution
to present day changes and for likely future
scenarios.
The impact of black
soot depositing on ice and snow in places
like the Arctic and mountain glaciers, such
as those in the Himalayas is also subject
to increasing investigation.
One paper in the Journal
of Geophysical Research suggests that eliminating
black carbon and other organic carbon emissions
might reduce net warming in the elevated
regions of Eurasia by 20 per cent to 45
per cent over 3-5 years.
Some Possible Actions
with Multiple Green Economy Benefits
Boosting the efficiency
of power stations and switching to cleaner
and renewable energies will not only cut
CO2 emissions but also reduce black carbon
emissions.
Fitting or retrofitting particle traps to
diesel vehicles, ideally in combination
with the introduction of ultra low sulphur
fuels, can also reduce black carbon emissions
while improving air quality and public health.
A paper in August 2009
in Foreign Affairs estimates that fitting
particle traps to one million semi-trailer
trucks would, over 20 years, yield climate
benefits equal to taking over 160,000 trucks
or 5.7 million cars off the road.
Mass introduction of
more efficient biomass-burning stoves and
cookers or introduction of solar cookers
would also have multiple benefits.
Some companies have
developed such stoves that cut black carbon
emissions by around 70 per cent using passive
air flows and better insulation; at the
same time, these stoves use 60 per cent
less wood, helping to save the forests and
reducing CO2 emissions.
UNEP has just launched
an Integrated Assessment of Black Carbon
and Tropospheric Ozone to evaluate their
role in air pollution and climate change.
Building on the UNEP
ABC project, measuring and monitoring of
black carbon and other atmospheric particles
is to be extended from the Asia-Pacific
region across Africa in order to pinpoint
'hot spots' where reducing emissions can
protect human health.
In addition, UNEP-ABC
is sponsoring Project Surya. This aims to
reduce black carbon emissions from cooking
with biomass and dung in rural India and
document its impact on the climate forcing,
health and regional climate.
Tropospheric including
Low Level Ozone
What is it?
Ozone is a gas that
near ground level is considered a pollutant,
often times called smog, because it impairs
human health and productivity of natural
systems such as forests.
Tropospheric ozone refers
to the ozone that is present in the atmosphere
from the ground up to about 15 km altitude
in the Tropics.
In this layer of the
atmosphere, most ozone is formed by pre-cursor
emissions from the surface, including volatile
organic compounds from petroleum products
and solvents and others like carbon monoxide
from fossil fuel burning.
In the presence of sunlight,
these can react to form ozone.
Low level ozone tends
to stay locally, whereas higher up it spreads
regionally and globally.
Unlike CO2, which can
remain in the atmosphere for centuries to
millennia, the pollutants that form ozone
persist for hours to months and the ozone
formed has a life of just a few days.
What is it doing?
In the European Union
more than 21,000 premature deaths annually
are associated with ground level ozone according
to the European Environment Agency.
It is estimated that
in 2000 in the European Union, well over
Euro 6 billion-worth of crops were lost
due to ozone.
Climate Change Links
The precise contribution
of tropospheric ozone to climate change
in the 21st century is, according to some
estimates, thought to be equal to between
15 per cent and 20 per cent of that caused
by all other greenhouse gases, including
CO2 and black carbon.
Some Possible Actions with Multiple Green
Economy Benefits
Boosting the fuel efficiency
of vehicles and moving to plug-in hybrids
and electric ones would cut some of the
emissions that allow tropospheric ozone
to form
Reducing emissions from
a variety of sources including leaks from
refineries and petrol stations to paint
products, paint shops and dry cleaners
The reactions that produce
the ozone run faster at higher temperatures-some
scientists suggest that simple measures
to reduce the urban heat-island effect,
by for example having white roofs on buildings
or more tree planting, could help to reduce
the ozone concentration
Methane
Methane is a gas emitted
naturally from swamps and other wetlands.
Human emissions of methane come mainly from
landfills and other sources such as oil
and gas facilities and livestock. The biggest
and growing source is from deforestation,
which is contributing up to 20 per cent
of emissions.
Methane has an atmospheric
life-time of around 12 years, although the
precise life-time depends on factors such
as temperature and concentrations of other
substances.
At the upcoming UN climate
convention meeting in Copenhagen, it is
hoped that governments will agree to an
agreement on Reduced Emissions from Deforestation
and forest Degradation (REDD).
This would essentially
pay developing countries to conserve forests
with the multiple likely benefits of improved
water supplies, soil stabilization, reduced
losses of biodiversity and employment in
resource management and eco-tourism.
UNEP, in cooperation
with the UN Development Programme (UNDP)
and the Food and Agricultural Organization
of the UN with funding from Norway, have
launched a UN REDD programme to prepare
nine pilot countries for a future REDD arrangement.
Under the Kyoto Protocol's
Clean Development Mechanism, developed countries
can invest in off-setting emissions by assisting
developing ones to reduce methane emissions
from sources such as landfills.
Other options include
emissions from untreated sewage and coal
mines.
Nitrogen compounds come
from a variety of sources including combustion,
vehicles, the livestock sector and fertilizer
use.
Some contribute to the
formation of tropospheric ozone whereas
other nitrogen compounds, for example nitrous
oxide which has an atmospheric lifetime
of about 114 years are greenhouse gases
in their own right.
The elevated concentration
of nitrous oxide alone contributes about
four per cent to climate change
Notes to Editors:
The Intergovernmental
Panel on Climate Change's fourth assessment
report http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm
The large contribution
of projected HFC emissions to future climate
forcing http://www.pnas.org/content/106/27/10949.full?sid=ee661dea-7bf6-4c47-8e96-c532edc76b78
Project Atmospheric
Brown Cloud http://www-abc-asia.ucsd.edu/
ABC Summary: regional
assessment report with focus on Asia http://www.unep.org/pdf/ABCSummaryFinal.pdf
UN Reduced Emissions
from Deforestation and forest Degradation
www.un-redd.org
Quantifying the impact
of current and future tropospheric ozone
on tree biomass, growth, physiology and
biochemistry: a quantitative meta-analysis-Global
Change Biology http://www3.interscience.wiley.com/journal/121482655/abstract?CRETRY=1&SRETRY=0
The 3rd World Climate
Conference www.wmo.int/wcc3/
For More Information Please Contact:
Nick Nuttall, UNEP Spokesperson and Head
of Media
