Section GCM: Climate models and projections

Transcription

1 Section GCM: Climate models and projections Outline GCM.1 Global climate models GCM.2 Using GCMs, Part 1: Attribution GCM.3 Using GCMs, Part 2: Future projections GCM.3.1 how to produce projections GCM.3.2 summary of projections by climate variable GEOG 313/513 Fall 2016 Global Climate Change 1 Prof J. Hicke

2 Learning outcomes Section GCM: Climate models and projections explain what climate models are, why they are useful, what causes variability among models, and which are the most uncertain aspects of models understand how models are used to attribute observed change to human activities describe how future projections are developed discuss general changes expected in the coming decades for climate variables (temperature, precipitation, sea level, cryosphere, extreme events) GEOG 313/513 Fall 2016 Global Climate Change 2 Prof J. Hicke

3 Section GCM: Climate models and projections Outline GCM.1 Global climate models GCM.2 Using GCMs, Part 1: Attribution GCM.3 Using GCMs, Part 2: Future projections GCM.3.1 how to produce projections GCM.3.2 summary of projections by climate variable GEOG 313/513 Fall 2016 Global Climate Change 3 Prof J. Hicke

4 Climate model representation Kitchen, Pearson Education, Inc. Global Climate Change 4 Prof J. Hicke

5 Climate model representation Henderson-Sellers, 1987 Global Climate Change 5 Prof J. Hicke

6 Climate model components/systems www2.ucar.edu/news/understanding-climate-change-multimedia-gallery Global Climate Change 6 Prof J. Hicke

7 Advances in model complexity Global Climate Change 7 Prof J. Hicke

8 Many GCMs Slide courtesy J. Abatzoglou Global Climate Change 8 8 Prof J. Hicke

9 AGCM = atmospheric GCM Edwards, 2010 Global Climate Change 9 Prof J. Hicke

10 IPCC AR5 resolution: 0.5º-4º ( km) IPCC, AR4, 2007 Global Climate Change 10 Prof J. Hicke

11 Finer spatial resolution: improved representation of mountains Global Climate Change 11 Prof J. Hicke

12 observations Comparing model results to observations Global Climate Change IPCC, AR4, Prof J. Hicke

13 GCM evaluation and changes from AR4 to AR5 IPCC, AR5, 2013 Global Climate Change 13 Prof J. Hicke

14 GCM evaluation in the Pacific Northwest Rupp et al., J. Geophysical Research, 2013 Global Climate Change 14 Prof J. Hicke

15 GCM evaluation in the Pacific Northwest Rupp et al., J. Geophysical Research, 2013 Global Climate Change 15 Prof J. Hicke

16 GCM evaluation in the Pacific Northwest relative error Rupp et al., J. Geophysical Research, 2013 Global Climate Change 16 Prof J. Hicke

17 Section GCM: Climate models and projections Outline GCM.1 Global climate models GCM.2 Using GCMs, Part 1: Attribution GCM.3 Using GCMs, Part 2: Future projections GCM.3.1 how to produce projections GCM.3.2 summary of projections by climate variable GEOG 313/513 Fall 2016 Global Climate Change 17 Prof J. Hicke

18 Attribution of climate change to human activities Attribution of climate change to anthropogenic causes involves statistical analysis and the assessment of multiple lines of evidence to demonstrate that the observed changes are (1) unlikely to be due entirely to natural internal climate variability; (2) consistent with estimated or modeled responses to the given combination of anthropogenic and natural forcing; and (3) not consistent with alternative, physically plausible explanations of recent climate change IPCC, AR4, WG II, 2007 Global Climate Change 18 Prof J. Hicke

19 sea ice trend What is detection? What is attribution? temperature trends ocean heat content trends IPCC 2013 WGI report Global Climate Change 19 Prof J. Hicke

20 Section GCM: Climate models and projections Outline GCM.1 Global climate models GCM.2 Using GCMs, Part 1: Attribution GCM.3 Using GCMs, Part 2: Future projections GCM.3.1 how to produce projections GCM.3.2 summary of projections by climate variable GEOG 313/513 Fall 2016 Global Climate Change 20 Prof J. Hicke

21 Integrated Assessment Models feedings GCMs van Vuuwen, Climatic Change, 2011 Global Climate Change 21 Prof J. Hicke

22 Representative Concentration Pathways (RCPs) RCP population growth GDP technology development fossil fuel use climate policy 2.6 moderate high high low aggressive (e.g., carbon capture/storage) 4.6 moderate high intermediate medium moderate 6.0 moderate low intermediate mediumhigh some 8.5 high low low high none Global Climate Change 22 Prof J. Hicke

23 Drivers behind RCP: Population and GDP van Vuuren et al., 2011 Global Climate Change 23 Prof J. Hicke

24 Representative Concentration Pathways (RCPs) CO2 emissions (fluxes) CO2 concentrations (stocks) Inman, Nature Climate Change, 2011 en.wikipedia.org/wiki/representative_concentration_pathways#media viewer/file:all_forcing_agents_co2_equivalent_concentration.png Global Climate Change 24 Prof J. Hicke

25 Radiative forcing of different RCPs anthropogenic aerosols IPCC, AR5, WGI, 2013 Global Climate Change 25 Prof J. Hicke

26 Different physical representations lead to different projections for same GCM Betts et al., Phil. Trans. Royal Society, 2011 Global Climate Change 26 Prof J. Hicke

27 Model-tomodel variability IPCC, AR5, WGI, 2013 Global Climate Change 27 Prof J. Hicke

28 Warming projections IPCC, AR5, WGI, 2013 Global Climate Change 28 Prof J. Hicke

29 Increasing T for higher RCP, later periods Global Climate Change 29 IPCC, AR5, Prof WGI, J Hicke

30 Projected Precipitation Change (%) Model Mean, RCP minus Global Climate Change IPCC, AR5,30WGI, 2013 Prof J. Hicke

31 Changes in precipitation ( minus ) National Climate Assessment, 2014 Global Climate Change 31 Prof J. Hicke

32 Seasonal variability in precip changes Pacific Northwest Northwest Region, National Climate Assessment, 2014 Global Climate Change 32 Prof J. Hicke

33 Northern Hemisphere Snow Cover Mar-Apr Fig 12.32, IPCC AR5, WG1 Global Climate Change 33 Prof J. Hicke

34 Arctic sea ice extent Ice Free Arctic by 2050? Fig 12.28, IPCC AR5, WG1 Global Climate Change 34 Prof J. Hicke

35 Antarctic sea ice extent IPCC AR5, WG1 Global Climate Change 35 Prof J. Hicke

36 Warmer, warmer, warmer IPCC, AR5, WGI, 2013 Global Climate Change 36 Prof J. Hicke

37 Change in heaviest 5 consecutive days of precipitation per year IPCC, AR5, WGI, 2013 Global Climate Change 37 Prof J. Hicke

38 Change in the annual longest string of dry days IPCC, AR5, WGI, 2013 Global Climate Change 38 Prof J. Hicke

39 Abrupt or irreversible change abrupt = a large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems IPCC, AR5, WGI, 2013 Global Climate Change 39 Prof J. Hicke

40 Beyond 2100 IPCC, AR5, WGI, 2013 Global Climate Change 40 Prof J. Hicke