Published : Mar 14,
2013 Last modified : Mar 14, 2013 12:25
PM
Emissions of air pollutants and greenhouse
gases from the shipping sector have increased
substantially in the last two decades, contributing
to both climate change and air pollution
problems, according to a report from the
European Environment Agency (EEA).
The shipping sector needs an integrated
monitoring, reporting and verification system
for emissions in European waters to systematically
address both types of emissions together,
the report says.
Air pollutants emitted
by shipping can affect air quality in many
areas, particularly around ports and busy
shipping channels. The release of greenhouse
gases and air pollutants from international
shipping has a complex effect on the climate
- greenhouse gas emissions have a warming
effect, while on the other hand some air
pollutants lead to cooling.
Jacqueline McGlade,
EEA Executive Director, said: “This study
shows the complex effects different emissions
are having on the planet. We need initiatives
that protect the environment as an overall
system. The choice between either clean
air or mitigating climate change is a false
dichotomy - Europe needs both. By avoiding
unnecessary movement of goods and improving
transport efficiency, we can address both
air pollution and greenhouse gas mitigation
together.”
At the global level,
the combined emissions from ships have a
net cooling effect on the climate, according
to recent scientific literature. This is
because these aerosols directly scatter
some radiation and indirectly lead to cloud
formation. The overall cooling effect is
rather uncertain. Nevertheless, it seems
that the cooling effect of aerosols is currently
larger than the warming effect of greenhouse
gas emissions.
The EEA has also carried
out a model simulation which shows that
the direct aerosol cooling effect may be
slightly reduced by new EU rules on sulphur
content in ship fuels. However, there is
still some uncertainty as changes in cloud
formation and other direct and indirect
effects are not taken into account in this
modelling.
Shipping’s air pollution
problem
Compared to other economic
sectors, shipping is currently one of the
most unregulated sources of air pollution.
The report highlights that some success
has been achieved through EU legislation,
especially on sulphur content of marine
bunker fuels where limits are stricter than
the international standards.
Air pollution from shipping
harms health, increasing heart disease,
respiratory illnesses and premature death
in some cases. Some of these air pollutant
emissions also damage the environment through
acidification and eutrophication.
While some air pollutants
are emitted far from land, around 70 % of
the global emissions from ships are within
400 km of coastlines, and this rate is much
higher in European waters. Moreover, some
pollutants from ships can travel hundreds
of kilometres in the atmosphere.
In some areas, ships
can contribute up to 20-30% of the local
fine particulate matter (PM2.5) concentrations.
Around some busy ports and shipping channels
ships can contribution as much as 80 % of
nitrogen oxide (NOx) and sulphur dioxide
(SO2) pollution. The report highlights that
there are relatively few measurement data
available to attribute shipping’s contribution
to local air pollution, although there are
some modelling studies.
Shipping and carbon
emissions
In 2007 national and
international shipping was responsible for
3.3 % of global carbon dioxide (CO2) emissions
– and around 30 % of this is emitted on
routes passing through European ports. Emissions
from the sector are projected to grow by
up to 4 % per year over the next decade.
There is a clear link
between economic growth and the movement
of goods, so emissions from shipping currently
change in step with the level of economic
activity. Carbon dioxide emissions from
international shipping departing from EU
ports increased by approximately 35 % between
11000 and 2010. Other key pollutants have
increased between 35 and 55 % over the same
period. However, most emissions types have
decreased since 2006, possibly due to the
economic downturn and the legislation reducing
SO2 levels.
Curbing air pollution
and greenhouse gases together
The report shows that
reducing fuel consumption is the best way
to reduce emissions. Better fuel efficiency
may be the easiest way to cut both air pollution
and greenhouse gases, the report says, recommending
technical improvements and also different
ship operating procedures. If ships reduced
their speed by 10 %, known as ‘slow steaming’,
it could cut energy demand by approximately
19 %, according to one study. Some shipping
sectors are already switching to liquid
natural gas (LNG), leading to an eradication
of SO2 emissions, 80 % reduction of NOx
and 20 % reduction of CO2.
‘End-of-pipe’ emissions
reductions technologies such as sea water
scrubbing can also reduce air pollutants,
but would not address greenhouse gases.
Environmental legislation
Against the background
of challenges presented by global trade
operations, ships registered in many different
countries and marine fuel bunkered in any
location in the world, there is currently
considerable debate on the regulation of
emissions from the shipping sector. The
report provides an overview of the various
topics that need to be addressed, ranging
from ship registration to atmospheric modelling
of air quality and climate impacts.
