Emissions
of methane (CH4)
OD-8
Ozone
Depletion
Pressure
1 Indicator
definition and unit of measurement
Total
anthropogenic CH
4
emissions from the sectors energy, industrial processes, solvent and other
product use, agriculture, land use change and forestry, and waste (as defined
by IPCC). Unit of measurement is tonnes CH
4
per year. See indicator “Emissions of CH
4”
in the Climate Change section.
2 Placement
in the framework
5EAP:
See
indicator “Emissions of CH
4”
in the Climate Change section.
Agenda
21:
See
indicator “Emissions of CH
4”
in the Climate Change section.
International
conventions and agreements:
See
indicator “Emissions of CH
4”
in the Climate Change section.
Ranking:
Core
ranking:
8
(19%)
Policy
Relevance:
10
(2.2)
Analytical
Soundness:
10
(2 )
Responsiveness:
8
(2.6)
Most
appropriate related state indicator:
Stratospheric
concentration of CH
4,
overall ozone depletion potential.
3 Significance
Purpose:
The
purpose of the indicator is to measure anthropogenic CH
4
emissions. Stratospheric CH
4
has three major effects on stratospheric ozone concentrations. 1) Stratospheric
CH
4
reacts with chlorine compounds, leading to less ozone destruction, 2)
Stratospheric CH
4
produces a significant amount of H
2O.
Stratospheric H
2O
increases the destruction of ozone, 3) CH
4
emissions contribute to the cooling of the stratosphere. This will on the one
hand decrease the effects of ozone depleting substances, and on the other hand
increase the formation of polar stratospheric clouds. The latter might largely
increase the depletion of stratospheric ozone in the future (see the indicator
“Emissions of CO
2”
in this section).
Overall,
an increase in CH
4
emissions is expected to result in a faster recovery of the ozone layer in the
first half of the next century.
Relevance:
The
relevance of the indicator is highly disputable from a policy viewpoint.
Although CH
4
emissions
are expected to have a positive effect on the ozone layer, these emissions are
one of the main causes of the enhanced greenhouse effect. CH
4
emission reductions are therefore justified.
Linkages
to other pressure indicators:
The
indicator is one of the most important indicators for climate change.
Furthermore, since stratospheric ozone affects the greenhouse effect, ozone
depletion should be considered in assessing climate change.
Targets:
See
indicator “Emissions of CH
4”
in the Climate Change section.
4 Methodological
description and underlying definitions
Underlying
definitions and concepts:
See
indicator “Emissions of CH
4”
in the Climate Change section.
Measurement
methods:
See
indicator “Emissions of CH
4”
in the Climate Change section.
Limitations
of the indicator:
See
3. Relevance.
Alternative
definitions:
None.
