Title: UNFCCC Article 2 Article 6, Stabilisation scenarios under Uncertainty A webbased climate model for g
1UNFCCC Article 2 ltgt Article 6, Stabilisation
scenarios under Uncertainty A web-based climate
model for global dialogue
- Ghent 17Nov 2003
- Ben Matthews matthews_at_climate.be
- Jean-Pascal van Ypersele vanyp_at_climate.be
- Institut dastronomie et de géophysique G.
Lemaître, - Université catholique de Louvain,
Louvain-la-Neuve, Belgium - Web www.climate.be (UCL-ASTR)
- jcm.chooseclimate.org (interactive model)
- JCM also developed with DEA-CCAT Copenhagen,
UNEP-GRID Arendal, KUP Bern
2UN Framework Convention on Climate Change
Ultimate objective (Article 2)
- '...stabilization of greenhouse gas
concentrations in the atmosphere at a level that
would prevent dangerous anthropogenic
interference with the climate system. - Such a level should be achieved within a time
frame sufficient - - to allow ecosystems to adapt naturally to
climate change, - - to ensure that food production is not
threatened and - - to enable economic development to proceed in a
sustainable manner.'
(technologies, lifestyles, policy
instruments) Emissions pathways(biogeochemical
cycles) Critical Levels (global temperature /
radiative forcing) Critical Limits (regional
climate changes) Key Vulnerabilities
(socioeconomic factors)
inverse calculation
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4European Union 2 C limit
- EU Council Of Ministers 1996
- "...the Council believes that global average
temperatures should not exceed 2 degrees Celsius
above pre-industrial level and that therefore
concentration levels lower than 550 ppm CO2
should guide global limitation and reduction
efforts." - "This means that the concentrations of all GHGs
should also be stabilised. This is likely to
require a reduction of emissions of GHGs other
than CO2, in particular CH4 and N2O" - However, widely varying interpretations of
implications for emissions! - Why? Java Climate Model may help to
investigate...
5- Stabilisation scenarios in Java Climate Model
- (Article 2 critical limits gt critical levels gt
emissions pathways) - Inverse calculation to stabilise
- CO2 concentration (as IPCC "S"/ WRE scenarios)
- Radiative Forcing (all-gases, "CO2 equivalent")
- Global Temperature (e.g. to stay below 2C limit)
- (Sea-level -difficult due to inertia in ocean /
ice) - JCM Core science very similar to IPCC-TAR models,
but (unlike TAR SYR) includes mitigation of all
greenhouse gases and aerosols. - Iterative method to find concentrations attaining
specified forcing/temperature. Very fast
response. - Explore interactively by dragging target curve
with mouse. - Or systematically calculate probabilistic
analysis ...
6- 81 Carbon cycle variants
- 3 Land-use-change emissions (Houghton, scaled),
- 3 CO2 fertilisation of photosynthesis ("beta"),
- 3 Temperature-soil respiration feedback ("q10"),
- 3 Ocean mixing rate (eddy diffusivity of
Bern-Hilda model) - 6 Ratios of emissions of different gases
- Emissions of all gases (including CH4, N2O, HFCs,
Aerosol and Ozone precursors) reduced by same
proportion as CO2 with respect to one of six SRES
baseline scenarios - note atmospheric chemistry feedbacks included,
but not varied - 84 Forcing/Climate Model variants
- 3 Solar variability radiative forcing
- 4 Sulphate aerosol radiative forcing
- 7 GCM parameterisations climate sensitivity,
ocean mixing/upwelling, surface fluxes (W-R UDEB
model tuned as IPCC TAR appx 9.1) - note for sea-level rise, should add uncertainty
in Ice-melt parameters
7Probability from fit to historical data
- Relative probability of each set of parameters
derived from inverse of "error" (model - data) - Measured global temperatures (CRU proxies)
- Measured CO2 concentration (Mauna Loa others)
- Reject low-probability variants (kept 468 / 6804)
- Ensures coherent combinations of parameters, e.g.
- More sensitive climate models with higher
sulphate forcing - High historical landuse emissions with higher
fertilisation factor - Still 2808 curves per plot (including 6 SRES per
set)So show 10 cumulative frequency bands
(using probabilities)
8 Carbon Cycle
Other gases/Aerosols
Climate Model
9 Carbon Cycle
Other gases/Aerosols
Climate Model
10What CO2 level stabilises Tlt 2C ?
- Range 380 - 620ppm,
- Mean 475ppm, Median 450ppm.
- Over 90 of variants are below 550ppm so a
550ppm target has a high risk of exceeding 2C - If we want 90 of variants below 2C,the
concentration should not exceed 400ppm ! - note 550ppm "CO2 equivalent" (all gases) would
bring us close to 2C. However, to keep the
temperature level, total radiative forcing (and
hence CO2 equivalent) must decline gradually.
This is possible while CO2 remains level, due to
declining CH4 and O3 (short lifetime gases).
11Shifting the Burden of Uncertainty
- On average, all sets of scenarios stabilise at
the same temperature level of 2C above
preindustrial level. But their uncertainty
ranges are very different! - (note picture in abstract book)
- A Temperature limit rather than a Concentration
limit reduces the uncertainty for Impacts/
Adaptation... - (assuming we commit to adjust emissions to stay
below the limit, as the science evolves) - ...however this increases the uncertainty
regarding emissions Mitigation pathways. - Which is better?
12If using costs to analyse choice of policy tool /
regime, beware that ...
- A target closer to emissions source (e.g. C-tax,
intensity, etc) might reduce cost of uncertainty
for mitigators, but increase it for those
responding to climate impacts. The chain has two
ends! - Using cost analysis for quota-allocation creates
an incentive to exploit scientific uncertainties,
each party overstating its mitigation costs and
understating its gain from avoided regional
climate impacts. A good regime should encourage
honesty in risk assessment! - Including adaptation costs may help to balance
this game?
13Role-play on Article 2 with students Louvain la
Neuve, Belgium, Dec 2002, as if COP11, Moscow,
Dec 2005 UNFCCC-style-process,17 teams of
National NGO delegates.
- Quantitative interpretation of Article 2
Temperature rise (lt1.9C 2100-1990) Sea-level
rise (46cm 2100-1990) - Principles for Adaptation funds Tax on
emissions trading / JI (/CDM?) Percapita
emissions GDP formula - Final compromise between Russia and Tuvalu (after
US quit) - Equity implications were key aspect of discussion
- Scientific inconsistency maybe realistic in
policy compromises? - Delegates used Java Climate Model to explore
options / uncertainties. By selecting parameters
/ indicators, same model can "justify" diverse
positions! - Such "games" also help us to identify scientific
issues.Reconciling multi-criteria climate
targets, Conversion to CO2 "equivalents" - To be reenacted at COP9 Milano side-event Fri 12
Dec 1pm!
14Article 2 needs global dialogue (Art 6)
- Risk/Value Judgements (including equity
implications) - Impacts Key Vulnerabilities? Acceptable level
of Change? - Risk Target Indicator? Acceptable Level of
Certainty? - (choice of target indicator shifts the burden of
uncertainty) - Such risk/value decisions cannot be made by
scientific experts alone. - The ultimate integrated assessment model
remains the global network of human heads. - To reach effective global agreements, we need an
iterative global dialogue including citizens /
stakeholders. The corrective feedback process is
more important than the initial guess. So let's
start this global debate!
15Experiment with Java Climate Model
Try JCM at jcm.chooseclimate.org Works in web
browser, Instantly responding graphics, Based on
IPCC-TAR methods / data, Open-source, Labels in
10 languages, 50000 words documentation JCM also
used for teaching in several countriesUniv Cath
de Louvain (BE) Open University (UK), Univ Bern
(CH), Univ Washington (CA),... Role-play
"games" with students may be a useful way to
experiment wth the dialogue process and identify
related scientific questions. Longterm Vision
link such courses to make real global dialogue
linking students around the world. Please join in!
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19Use of Java Climate Model in Role-Play
- (Belgium, Denmark, Russia, USA, Australia,
Saudi-Arabia, Venezuela, Brazil, Burkina-Faso,
Marroco, Tuvalu, India, Greenpeace, GCC, FAO,
WB/IMF, Empêcheurs) - Delegates used JCM to explore options and
uncertainties - By selecting different parameters, same model can
"justify" diverse positions, from India to
Australia, Burkina Faso to Saudi Arabia. - Such "games" also help us to identify key science
/policy questions. - areas of potential confusion - e.g. definition of
CO2 equivalents - how to handle potentially inconsistent
multi-criteria targets - JCM also used for teaching in several
countriesOpen University (UK), Univ Bern (CH),
Univ Washington (CA),... - Longterm Vision link such courses to experiment
with real global dialogue between students around
the world.
20Article 2 in IPCC AR4
- IPCC Plenary decided the scientific, technical,
and socio-economic issues associated with Article
2 would be a cross-cutting theme in AR4. -
- Scoping paper suggests steps
- gtAssess Key Vulnerabilities using WEHAB
framework - gtCritical Limits (Thresholds) of climate
parameters - gtCritical Levels (e.g. Concentrations)
- gtPossible Emissions Pathways
- All steps within a Risk / Uncertainty framework
21Risk and Value Judgements
- The global dialogue needs a quantitative
framework. In practice, this will revolve around
simple indicators, e.g. Global annual average
Temperature, CO2 (equivalent?) concentration. - Interface with computer models essential to
consider complex interacting issues and feedback
processes. The Java Climate Model (JCM) enables
anybody to explore both policy options and
scientific uncertainties, simply by dragging
controls on plots in a web browser.
22Caveats
- Climate Sensitivity not well constrained by
historical temperatures. May be higher than TAR
model range (and increasing at higher
temperatures). - Mitigation of other gases in proportion to CO2
reduction (w.r.t. SRES) is a simplistic
assumption. Better to have a socioeconomic/landuse
model. - Several uncertain factors not yet varied
Atmospheric chemistry, Ice-melting etc. - Shape of land-use emissions curve influences
terrestrial carbon-cycle balancing - Regional seasonal changes can be very different
from global average!
23 Inertia in the climate systemStabilising CO2
alone doesn't stabilise temperature (as below
from TARSYR Q6)However stable CO2 may correspond
to stable Temperature if other gases with shorter
lifetimes are also mitigated to a similar extent.