Climate Change Scenario, Climate Model and Future Climate Projection

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Model and Future Climate Projection A.K.M. Saiful Islam Professor Institute of

1 Training on Concept of Climate Change: Impacts, Vulnerability, Adaptation and Mitigation 6 th December 2016, CEGIS, Dhaka Climate Change Scenario, Climate Model and Future Climate Projection A.K.M. Saiful Islam Professor Institute of Water and Flood Management Bangladesh University of Engineering and Technology (BUET)

2 Outline of the presentation Understanding Global warming and climate change. Climate change and natural variability. Climate Change Scenarios, Global and regional Climate Change Modeling Regional Climate Change predictions for Bangladesh Impact of water, agriculture, floods and coastal ecosystems

3 Global warming and climate change

4 Climate Systems The complicated system consisting of various components, including the dynamics and composition of the atmosphere, the ocean, the ice and snow cover, the land surface and its features, the many mutual interactions between them, and the large variety of physical, chemical and biological processes taking place in and among these components. Climate refers to the state of the climate system as a whole, including a statistical description of its variations. Composition of Atmosphere 78% nitrogen, 21% oxygen, and 1% other gases. Carbon dioxide accounts for just %. Water vapor 0 to 2%

5 Components of Climate System

blanket for the thermal radiation from the surface which enables it to be

6 Climate Change, Global Warming and Green House Effect Co2 and some minor radioactively active gases are (known as greenhouse gases) acted as a partial blanket for the thermal radiation from the surface which enables it to be substantially warmer than it would otherwise be, analogous to the effect of a greenhouse

8 CO2 constantly increasing after industrializations since 1880 and so does the temperature

9 In 2016, CO2 topped 400ppm

10 Global temperature constantly rising since 1880 This July temperature anomaly of 0.84 degrees Celsius above average , according to NASA.

11 Surface Air temperature ( )

12 Trends of Sea Surface temperature

13 Changes of Sea Surface Temperature

14 Trends of Global Land Precipitations Time series for 1900 to 2005 of annual global land precipitation anomalies (mm) with respect to the 1981 to 2000 base period

http://www.nasa.gov/topics/earth/features/2012-seaicemin.

15 Arctic Sea Ice melting Images gathered from the Defense Meteorological Satellite Program of NASA show the minimum Arctic sea ice concentration 1979 (left) and 2003 (right) Yellow line represents Area 30 years before

16 Arctic Sea Ice Extent (2016)

17 Cracks in Ice bars

Sea level rise Sea level rise is caused primarily by two factors related to global warming: the added water from melting land ice and the expansion of sea water as it warms.

18 Sea level rise Sea level rise is caused primarily by two factors related to global warming: the added water from melting land ice and the expansion of sea water as it warms. The first chart tracks the change in sea level since 1993 as observed by satellites. The second chart, derived from coastal tide gauge data, shows how much sea level changed from about 1870 to

19 Decreasing Land Ice Data from NASA's GRACE satellites show that the land ice sheets in both Antarctica and Greenland are losing mass. The continent of Antarctica has been losing about 134 billion metric tons of ice per year since 2002, while the Greenland ice sheet has been losing an estimated 287 gigatones per year. (Source: GRACE satellite data)

20 Climate Change Scenarios and Climate Modeling

21 Climate Models Climate models are computer-based simulations that use mathematical formulas to re-create the chemical and physical processes that drive Earth s climate. To run a model, scientists divide the planet into a 3-dimensional grid, apply the basic equations, and evaluate the results. Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and evaluate interactions with neighboring points. Climate models use quantitative methods to simulate the interactions of the atmosphere, oceans, land surface, and ice.

23 General Circulation Model (GCM) General Circulation Models (GCMs) are a class of computerdriven models for weather forecasting, understanding climate and projecting climate change, where they are commonly called global Climate Models. Three dimensional GCM's discretise the equations for fluid motion and energy transfer and integrate these forward in time. They also contain parameterizations for processes - such as convection - that occur on scales too small to be resolved directly. Atmospheric GCMs (AGCMs) model the atmosphere and impose sea surface temperatures. Coupled atmosphere-ocean GCMs (AOGCMs, e.g. HadCM3, EdGCM, GFDL CM2.X, ARPEGE- Climate) combine the two models.

24 GCM typical horizontal resolution of between 250 and 600 km, 10 to 20 vertical layers in the atmosphere and sometimes as many as 30 layers in the oceans.

26 How do we model climate?

27 Global Climate Models

28 Grids of Global Climate Models Complicated choices starting from how to grid the globe.

31 Heart of Climate Model Conservation of momentum Conservation of mass Conservation of energy

33 Dynamic core of GCM AGCMs consist of a dynamical core which integrates the equations of fluid motion, typically for: surface pressure horizontal components of velocity in layers temperature and water vapor in layers radiation, split into solar/short wave and terrestrial/infra-red/long wave parameters for: convection land surface processes albedo hydrology cloud cover

34 GCM Solver AGCM contains prognostic equations that are a function of time (typically winds, temperature, moisture, and surface pressure) together with diagnostic equations that are evaluated from them for a specific time period. OGCMs model the ocean (with fluxes from the atmosphere imposed) and may contain a sea ice model. For example, the standard resolution of HadOM3 is 1.25 degrees in latitude and longitude, with 20 vertical levels, leading to approximately 1,500,000 variables.

35 Complexity of GCM: Past, present and future

37 Hardware Behind the Climate Model Geophysical Fluid Dynamics Laboratory

38 A few GCMs BCC-CM1: Agency Beijing Climate Center, National Climate Center, China Meteorological Administration, No.46, S.Road, Zhongguancun Str., Beijing , China BCCR: Bjerknes Centre for Climate Research (BCCR), Univ. of Bergen, Norway CGCM3: Canadian Centre for Climate Modelling and Analysis (CCCma) CNRM-CM3: Centre National de Recherches Meteorologiques, Meteo France, France CONS-ECHO-G: Meteorological Institute of the University of Bonn (Germany), Institute of KMA (Korea), and Model and Data Group. CSIRO: Commonwealth Scientific and Industrial Research Organisation, Australia

39 A few GCMs..(contd.) INMCM3.0: Institute of Numerical Mathematics, Russian Academy of Science, Russia. GFDL: Geophysical Fluid Dynamics Laboratory, NOAA NASA-GISS-AOM: NASA Goddard Institute for Space Studies (NASA/GISS), USA MRI-CGCM2_3_2: Meteorological Research Institute, Japan Meteorological Agency, Japan NCAR-PCM: National Center for Atmospheric Research (NCAR), NSF (a primary sponsor), DOE (a primary sponsor), NASA, and NOAA NIES-MIROC3_2-MED: CCSR/NIES/FRCGC, Japan UKMO-HADCM3: Hadley Centre for Climate Prediction and Research, Met Office, UK

40 Accuracy of climate model predictions Average precipitation Temperature anomaly (a) Observed ( ) (b) Predicted IPCC, 2007

41 How Well Do Climate Models Work? Pretty Good.

42 Importance of anthropogenic contribution

43 Variability exists among models IPCC, 2007

44 Climate models: Limitations Low resolution limits the ability to predict features such as tornadoes, etc Can t predict East Asian or Indian monsoons well Regional scale climatic features are difficult to predict accurately

45 Climate Change Scenarios and Predictions

46 Climate Change Scenarios Scenarios for future changes in external forcing have to be selected. Representative concentration pathways (RCP) scenarios provide a large range of future change in radiative forcing.

47 Projected Annual Green House Gas Emission Changes of CO2 emission for each RCP

48 RCP Scenarios RCP scenarios provide estimates for future concentration of greenhouse gases, aerosols, land use changes Global emission (in PgC per year) and (b) atmospheric concentration of CO 2 (in ppm) in four RCP scenarios.

49 Future Projection of Green House Gas

Changes in global mean surface temperature The magnitude of the surface warming is strongly different in the RCP scenarios, showing the potential impact of mitigation policies.

50 Changes in global mean surface temperature The magnitude of the surface warming is strongly different in the RCP scenarios, showing the potential impact of mitigation policies. Time series of global annual mean surface air temperature anomalies (relative to ) from an ensemble of model simulations performed in the framework of CMIP5. Figure from Collins et al. (2013).

51 Long term Global Average Surface warming

Spatial distribution of surface temperature changes Multi-model mean of surface temperature change for the scenarios RCP2.6 and RCP8.5 in 2081 2100 relative to 1986-2005.

52 Spatial distribution of surface temperature changes Multi-model mean of surface temperature change for the scenarios RCP2.6 and RCP8.5 in relative to Hatching indicates regions where the multi model mean change is less than one standard deviation of internal variability. Stippling indicates regions where the multi model mean change is greater than two standard deviations of internal variability and where 90% of models agree on the sign of the change. Figure from Stocker et al. (2013)

54 Near Term projections of global mean temperature

55 Predicted Arctic sea Ice Results from community climate system models Arctic Sea Ice in 2000 Arctic Sea Ice in 2040

56 Prediction of Sea level rise

57 Changes of Average Precipitation

58 Thank you

Water Stress, Droughts under Changing Climate

Water Stress, Droughts under Changing Climate Professor A.K.M. Saiful Islam Institute of Water and Flood Management Bangladesh University of Engineering and Technology (BUET) Outline of the presentation