Climate Change 2014 The recent conclusions of the IPCC. Lars Bärring Research scientist, SMHI Rossby Centre Swedish co-focal Point for IPCC

Transcription

1 Climate Change 2014 The recent conclusions of the IPCC Lars Bärring Research scientist, SMHI Rossby Centre Swedish co-focal Point for IPCC

2 IPCC Fifth Assessment Report (AR5) Stockholm September pages, >9 200 scientific papers Special Repors SREX SRREN Yokohama March 2014 >3000 pages, ~ sci. papers (2 volymes) Kampala 2011 Abu Dhabi 2011 >550 pages >1000 pages Berlin April ? pages, ~ sci. papers Synthesis Report Copenhagen November 2014 ~110 pages ( 5 references )

3 Change in global mean temperature ( C) sea level (m) CO 2 (ppm green) metan (ppb orange) N 2 O (ppb red) CO 2 (Gton/yr) emissions from fossil fuel combustion (grey), and land use (yellow)

4 Change in global mean temperature (IPCC 2013, Fig. SPM.1a)

5 Annual global mean temperature ranks (UK Met. Office, July 2013)

6 How about the warming hiatus??

7 The hiatus in a context

8 2014 Sweden >2 C warmer than average for

9 Scenarios: SRES compared to RCP Gamla och Nya scenarier RCP8.5 ~ SRES A1FI ~SRES A1FI RCP4.5 ~ SRES B1 RCP6.0 ~ SRES A1B (Knutti and Sedlacek, Nature Climate Change, 2012, + own additions)

10 Uncertainty: Future vs. climate Global mean temperature change since ( C) Total anthropogenic emissions of CO 2 since 1870 (Gt CO 2 ) Total warming due to anthopogenic activites Warming due to fossil fuel burning Total anthorpogenic emissions of carbon since 1870 (Gt C) SYR Fig. 2.3 [Preliminary graphics, pending final proofing and copy editing]

11 Key message from WGI Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. Observed and simulated global mean temperature and ocean heat content Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system. WGI Fig. SPM.6 Simulations with both natural and anthropogenic climate forcing Simulations without human climate forcing Observations (10 year running mean)

12 SYR Fig. SPM.4 [Preliminary graphics, pending final proofing and copy editing]

13 Key message from WGII In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans. Evidence of climate-change impacts is strongest and most comprehensive for natural systems.. WIDESPREAD OBSERVED IMPACTS

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15 Change of emissions per country group and source Annual emissions of greenhouse gases (GtCO 2 eq/yr)

16 Change of emissions per country group Annual emissions of greenhouse gases (GtCO 2 eq/yr) consumption based production based

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18 Limiting Temperature Increase to 2 C Measures exist to achieve the substantial emissions reductions required to limit likely warming to 2 C A combination of adaptation and substantial, sustained reductions in greenhouse gas emissions can limit climate change risks Implementing reductions in greenhouse gas emissions poses substantial technological, economic, social, and institutional challenges But delaying mitigation will substantially increase the challenges associated with limiting warming to 2 C AR5 WGI SPM, AR5 WGII SPM,AR5 WGIII SPM IPCC AR5 Synthesis Report

19 Mitigation Measures More efficient use of energy Greater use of low-carbon and no-carbon energy Many of these technologies exist today Improved carbon sinks Reduced deforestation and improved forest management and planting of new forests Bio-energy with carbon capture and storage Lifestyle and behavioural changes AR5 WGIII SPM IPCC AR5 Synthesis Report

20 Ambitious Mitigation Is Affordable Economic growth reduced by ~ 0.06% (BAU growth 1.6-3%) This translates into delayed and not forgone growth Estimated cost does not account for the benefits of reduced climate change Unmitigated climate change would create increasing risks to economic growth AR5 WGI SPM, AR5 WGII SPM IPCC AR5 Synthesis Report