Klimamodeller og usikkerhet

Transkript

1 Klimamodeller og usikkerhet Terje Koren Berntsen 1,2 With contributions from: Ragnhild Skeie 2, Marit Holden 3, Magne Aldrin 3 and Gunnar Myhre 2 1 University of Oslo, 2 Center for International Climate and Environmental Research Oslo (CICERO), 3 Norwegian Computing Center

2 Jordas energibalanse Tallene er i W/m 2 Kilde: Stephens et al., Nature Geoscience, 2012

3 Daily Net Radiation Top of the atmosphere. ERBE satellite data

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5 GLOBAL SURFACE TEMPERATURE CHANGE Reviews of Geophysics Volume 48, Issue 4, pages n/a-n/a, 14 DEC 2010 DOI: /2010RG

6 Varmeinnholdet i havet øker Kilde: Levitus et al., Geofys. Res.Letters, 2012

7 Målinger av CO 2 i atmosfæren Kilde: NOAA, 2013 (

8 Sammenheng Temperatur og CO 2 Under istider mellomistider endrer temperaturen seg først og deretter CO 2 NB! Betyr ikke at CO 2 ikke er en drivhusgass som bidrar til oppvarming

9 Temperature Profile of the Atmosphere

10 Adding Greenhouse Gases. What happens? LW out from higher up (lower temperature, E=σT 4 ) Less radiation to space Positive energy balance The system warms until LW out and energy balance is restored Simple example: Double CO 2 concentrations New equilibrium Keep other factors constant Water vapour in the air Cloud distribution (4-D) Surface properties (snow cover, vegetation, etc.) Biogeochemical cycles (e.g. carbon cycle) Ocean currents Definition of ECS: New equilibrium with ΔT s = 1.1 ± 0.1K Equilibrium Climate Sensitivity (ECS): Global mean surface warming due to a sustained doubling of CO 2 in the atmosphere when the system has reached a new equilibrium.

11 Feedbacks in the climate system

12 Svante Arrhenius Beregnet at en dobling av CO 2 konsentrasjonen vil øke den globale temperaturen med 5 6 C. Nyere estimater gjerne litt lavere.

13 Partikler bidrar til både økt refleksjon og økt absorpsjon av solstråling global dimming

14 Radiative forcing since1750 (IPCC, 2007) Radiative forcing since 1850 (Skeie et al., 2011)

15 Global Climate Models

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17 Årsaker til observerte klimaendringer: IPCCs konklusjoner (2007) It is very likely that anthropogenic greenhouse gas increases caused most of the observed increase in globally averaged temperatures since the mid-20th century Discernible human influences now extend to other aspects of climate, including continental-average temperatures, atmospheric circulation patterns, and some types of extremes It is likely that greenhouse gases alone would have caused more warming than observed because volcanic and anthropogenic aerosols have offset some warming that would otherwise have taken place.

18 CO2 (ppm) Estimating climate sensitivity: Two approaches Historic forcing Climate system response Observed response Estimated climate sensitivity CO2 (ppm) Year Idealized Stepwise forcing in ESMs Calculated response in ESMs. CCSM3, Jonko et al. Range from CMIP5 ( K), Andrews et al., GRL, 2012

19 Nye Resultater fra UiO, CICERO og Norsk Regnesentral

20 Skeie et al. 2013, in review in Journal of Climate

21 ECS from global climate models in CMIP5 Andrews et al. Geophys. Res. Lett. 2012

22 Knowledge of ECS pdf of future warming and allowable emissions Meinshausen et al., Nature, 2009

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24 Isdekket i Arktis i September 2012 Kilde: NASA.

25 Nedbørendringer i Europa Kilde: KNMI og EEA:

26 Endringer i snødekket på nordlige halvkule (April-Juni) Kilde: Geophysical Research Letters Volume 39, Issue 19, L19504, 10 OCT 2012 DOI: /2012GL

27 Issmeltingen i Klimamodellene Stroeve, J. C. et al. (2012), Trends in Arctic sea ice extent from CMIP5, CMIP3 and observations, Geophys. Res. Lett., 39, L16502, doi: /2012gl

28 Modellering av karboninnhold i terrestriske økosystem Ahlstrøm et al., ERL, 2012

29 Ahlstrøm et al., ERL, 2012

30 Jiang, J. H., et al. (2012), J. Geophys. Res.,117, D14105, doi: /2011jd

31 Em (Pg(CO2)/yr) Tidsskalaer for utslipp konsentrasjon - temperatur Utslipp År

32 Em (Pg(CO2)/yr) og dco2(10ppm) Tidsskalaer for utslipp konsentrasjon - temperatur Utslipp Konsentrasjon (10 ppm) År

33 Em (Pg(CO2)/yr) og dco2(10ppm) dt(k) Tidsskalaer for utslipp konsentrasjon - temperatur Utslipp Konsentrasjon (10 ppm) Temperatur 1,4 1, ,8 15 0,6 10 0,4 5 0, År

34 FNs klimakonvensjon (1992), Kyotoavtalen (1997) og veien videre 1992: UNFCCC: FNs klimakonvensjon. Ratifisert av 155 land Rammeavtale, ingen konkrete forpliktelser 1997: Kyotoavtalen. Konkrete forpliktelser for utslipp for perioden for I-land. Ingen forpliktelser for U-land Fleksible mekanismer USA ratifiserer ikke avtalen 2011: Durban platform Mål: Avtale for 2020 klar i 2015 Alle land skal ha forpliktelser 2012: Kyoto-2 avtale i Doha ARTICLE 3 (UNFCCC): PRINCIPLES In their actions to achieve the objective of the Convention and to implement its provisions, the Parties shall be guided, INTER ALIA, by the following: 1. The Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof. 2. The specific needs and special circumstances of developing country Parties, especially those that are particularly vulnerable to the adverse effects of climate change, and of those Parties, especially developing country Parties, that would have to bear a disproportionate or

35 CO2 utslipp (Mtonn C/år) Globale fossile CO 2 utslipp Kyoto området Ikke regulert Totalt År Kilde: Carbon dioxide Information Centre (CDIAC)

36 Fleksible mekanismer i Kyotoavtalen

37 Løsningen ligger i energiforbruket Kilde: Solar Energy Perspectives. Rapport fra IEA, 2011.

38 Takk for oppmerksomheten