Emissions
of sulphur oxides (SOx)
CC-6
Climate
Change
Pressure
1 Indicator
definition and unit of measurement
Total
emissions of sulphur oxides. Natural emissions from e.g. volcanic eruptions are
not accounted for in this indicator. The unit of measurement is tonnes of
sulphur oxide emissions per year.
2 Placement
in the framework
5EAP:
Chapter
5: The themes and targets of the programme, section 5.1: Climate change and
section 5.2: Acidification and air quality.
Agenda
21:
Chapter
9: Protection of the atmosphere, section 2: Conservation and management of
resources for development.
International
conventions and agreements:
The
UNECE LRTAP (Geneva, 1979) and its 1985 (Helsinki) and 1994 (Oslo) protocols on
sulphur emissions.
Proposal
for a Council decision on the conclusion by the EC of the Protocol to the LRTAP
on further reduction of sulphur emissions (COM(97)88) is under discussion with
Member States (Directive to enter into force by 1.6.98).
Ranking:
Core
ranking:
6
(23%)
Policy
Relevance:
7
(2.8)
Analytical
Soundness:
5
(2.8)
Responsiveness:
2
(2.8)
Most
appropriate related state indicator:
Concentrations
of sulphates (as (NH
4)2SO2
), global temperature.
3 Significance
Purpose:
SOx
emissions produce sulphate aerosols in the troposphere. These aerosols cool the
climate in two ways: directly by scattering and absorbing radiation, and
indirectly by providing seeds for cloud formation. The main purpose of this
indicator is to monitor total emissions of SO
x.
Relevance:
Although
SO
x
emissions are the largest anthropogenic source of aerosols, the policy
relevance is very limited. Negative effects of SO
x
emissions, such as acidification and effects on human health, justify policies
to reduce SO
x
emissions.
Linkages
to other pressure indicators:
The
indicator is linked with those in the area of Climate Change, specifically to
the indicator for total emissions of aerosol particles (CC-7). The indicator is
furthermore related to the policy fields Air Pollution. See the corresponding
methodology sheets (e.g. AP-3 and AP-4).
Targets:
The
EU target is a 35% reduction of SO
2
in 2000 (1985 level).
4 Methodological
description and underlying definitions
Underlying
definitions and concepts:
Sulphur
oxides are mainly emitted by fossil fuel combustion (especially power
stations). SO
x
emissions are the largest anthropogenic source of aerosols. Over heavily
industrialised regions, aerosol cooling may counteract nearly all of the
warming effect of greenhouse gas emissions.
Measurement
methods:
The
1996 "Guidelines for National Greenhouse Gas Inventories” include SO
2
emissions. A more detailed methodology can be found in the joint EMEP/CORINAIR
(1996) “Atmospheric Emission Inventory Guidebook”.
Limitations
of the indicator:
The
cooling effect of aerosols has a geographical variation and is very difficult
to quantify. Therefore, the definition of a weighting factor to add this
indicator to the other climate change indicators will be difficult. Besides, SO
x
emissions are also included in the aggregated indicator for aerosol particles
(CC-7). See also 3. Relevance.
Alternative
definitions:
An
aggregated indicator for aerosol particles.
