[email protected]@climate.be [email protected] jcm.chooseclimate.org UNFCCC Article 2 Article 6, A web-based climate model for global dialogue

[email protected] [email protected] jcm.chooseclimate.org

UNFCCC Article 2 <=> Article 6, A web-based climate model for global

dialogueStabilisation scenarios under

Uncertainty

WCCC-2003 Москва

Ben Matthews [email protected]

Jean-Pascal van Ypersele [email protected]

Institut d’astronomie 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

mailto:[email protected]


UN 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)

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Role-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 (<1.9°C 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"



European 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...



Stabilisation scenarios in Java Climate Model(Article 2: critical limits => critical levels => 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 ...


Carbon Cycle Other gases/Aerosols

Climate Model


Shifting the Burden of UncertaintyOn average, all sets of scenarios stabilise at the same

temperature level of 2°C 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?


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 gasesEmissions 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 variants3 * 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


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)

Probability from fit to historical data


Carbon Cycle Other gases/Aerosols

Climate Model


What CO2 level stabilises T<= 2°C ?

Range: 380 - 620ppm,

Mean ~ 475ppm, Median ~ 450ppm.

Over 90% of variants are below 550ppm so a 550ppm target has a high risk of exceeding 2°C

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).



Article 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!



Try JCM at jcm.chooseclimate.orgWorks 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 countries:Univ 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!

Experiment with Java Climate Model


Documents

[email protected]@climate.be [email protected] jcm.chooseclimate.org UNFCCC Article 2 Article 6, A web-based climate model for global dialogue