Klimaatsverandering oor Suid-Afrika van die volgende paar dekades tot die einde van die eeu

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Arabella McDaniel
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1 Klimaatsverandering oor Suid-Afrika van die volgende paar dekades tot die einde van die eeu Francois Engelbrecht1 and Christen Engelbrecht2 1.WNNR Natuurlike Hulpbronne en die Omgewing 2.Landbou Navorsingsraad Insttuut vir Grond, Klimaat en Water

8 2015/ /98 Summer-season rainfall anomalies over the Free State and North West provinces (x-axis) and Niño 3.4 sea-surface temperature anomalies (y-axis) for Rainfall anomalies from CRU and GCPC are for DJF. SST anomalies from AMIPII are for 2016/17 OND. All anomalies were calculated with respect to the baseline period. CSIR-ACCESS

9 2015: the warmest year on record!

10 The 2015/16 El Niño (image from NOAA): One of the strongest events ever recorded. Strong El Niño s are projected to double in frequency towards the end of 21 st century under low mitigation

11 Drought in southern Africa In September 2016, the entire summer rainfall region was in a state of mild drought, or worse. The Free State, northern KwaZulu-Natal and eastern Mpumalanga was in a state of severe drought. A dust storm rolls over the plains of the Free State in December How will climate change impact on the attributes of drought in the megadam region of SA?

12 Drought in southern Africa By September 2016, The entire summer rainfall region of South Africa was in a state of mild drought, or worse. Depleted grazing in Kruger Park in September The Free State, northern KwaZuluNatal and eastern Mpumalanga was in a state of severe drought.

13 2015 warmest year ever recorded globally (+ 1 ºC); summer of 2015/16 the warmest ever recorded over southern Africa (+ 2 ºC) 2015/16 anomalies relative to 2006/7 to 2014/15 climate; ARC station data; Engelbrecht C et al. (2017) in preparation

14 Observed trends in annual-average temperatures over Africa (Engelbrect et al., 2015; ERL 10: ) Garland et al., 2015; Int J of Env Res and Public Health CSIR

parameterizations Developed by the CSIRO Marine and Atmospheric Research (McGregor, 2005) Runs in quasi-uniform or in stretched grid mode

15 Global climate modelling at the CSIR NRE NWP and RCM capacity build around the conformal-cubic atmospheric model (CCAM) of the CSIRO A cube-based global model; semi-lagrangian semi-implicit solution of the primitive equations Includes a wide range of physical parameterizations Developed by the CSIRO Marine and Atmospheric Research (McGregor, 2005) Runs in quasi-uniform or in stretched grid mode Multi-scale climate modelling. The first Africanbased earth system model VRESM is under development through a CSIRCSIRO collaboration CSIR

Regional climate modelling over Africa using CCAM CCAM applied in stretched-grid mode Modest stretching provides a resolution of about 8 km over southern Africa Development of Africa s first coupled

16 Regional climate modelling over Africa using CCAM CCAM applied in stretched-grid mode Modest stretching provides a resolution of about 8 km over southern Africa Development of Africa s first coupled climate model is in progress Development targets the main unresolved climate change questions for Africa and the SH in support of climate services A C192 stretched-grid with resolution about 8 km over southern Africa CSIR

HPC and codescalability Computer clusters available to the project include the CHPC in South Africa (24 000 + CPUs VRESM allocation is currently ~ 3 000 000 core hours per quarter); The VRESM design

17 HPC and codescalability Computer clusters available to the project include the CHPC in South Africa ( CPUs VRESM allocation is currently ~ core hours per quarter); The VRESM design has achieved some comparable resolution and computing times with less than 10% of the cores required by some more traditional coupling approaches. CSIR NRE data servers and CHPC VRESM allocated space currently amounts to 600 TB CCAM-TOM (CSIRO) scaling with 35 atmosphere levels and 30 ocean levels, suggestng excellent simulaton speed for computng resources

18 Emission Scenarios and Representatve Concentraton athways From CSIRO: Martn ix 2.6 Projected temp anomalies for relatve to pre-industrial conditons (0-degree world) AR5 WG1 estmatons relatve to were adjusted with a 0.6 C factor Only RCP 2.6 can safely keep us well below the Cancun agreed 2 C (Long Term Global Goal), whilst the world is currently between A2 and RCP 8.5 Scenario Temp anomalies relatve to preindustrial (adapted from AR5) RCP to 2.3 RCP to 3.2 RCP to 3.7 RCP to 5.4

19 CSIRO-CSIR collaboration: 0.5 resolution global climate change downscalings for CORDEX using CCAM Downscaling various CMIP5/AR5 CGCMs for different RCPs CSIR Martin Dix, CSIRO

20 CSIRO-CSIR collaboration: 0.5 resolution global climate change downscalings for CORDEX using CCAM Downscaling various CMIP5/AR5 CGCMs for different RCPs CSIR Martin Dix, CSIRO

21 More uncertainty surrounds the projected rainfall futures of Africa under climate change Southern Africa is projected to become generally drier by most models, whilst East Africa is projected to become generally wetter an El Niño signal! Figure: Projected changes in rainfall (mm) (left) and the average value of the Keetch-Byram drought index (right) over Africa for relative to CSIR Engelbrecht et al., 2015; ERL 10:

22 Projections of changing annual average temperature (degrees C) over southern Africa for the period relative to CSIR-CHPC

23 Projections of changing annual average temperature (degrees C) over southern Africa for the period relative to CSIR-CHPC

24 Projections of changing annual rainfall over southern Africa for the period relative to CSIR-CHPC

25 Projections of changing annual rainfall over southern Africa for the period relative to CSIR-CHPC

26 Climate Change and the seasonal cycle Regional climate models realistically represent the present-day seasonal cycle in rainfall and circulation across the African continent (Engelbrecht et al., 2009) Model projections of future climate change are generally not indicative of significant changes in the seasonal cycle of rainfall and temperature over Africa, however, significant changes are projected in the amplitude of seasonal extrema The most interesting changes are to be found on the application side, e.g. a changing seasonal cycle in energy demand and wild fires (e.g. Engelbrecht et al., 2015; ERL 10: ) Figure shows the present-day (black) and end-ofthe-century range of projected changes in the seasonal cycle of the Keetch-Byran drought index over southern and tropical Africa (Engelbrecht et al., 2015; ERL 10: )

27 3 ºC world Projected climate change futures for southern Africa: an El Niño signal? The Free State and North West province are projected to drift into a temperature climate regime never observed in recorded history 1.5 ºC world Temperature increases of 5-9 degrees C are plausible by the period Significant rainfall reductions are projected CSIR

28 Main messages related to the climate-change signal A robust pattern of drastic temperature rise is projected for southern Africa under the RCP8.5 and A2 scenarios an actionable climate change signal. Temperature increases are projected to range between 4 and 7 C over the interior by the end of the century increases larger than 6 C are plausible over much of semi-arid southern Africa under low mitigation. Temperature increases may plausibly reach 3-4 C by the 2040s Drastic increases in the number of high fire-danger days, very hot days and heat-wave days are projected to across the African continent under low mitigation. The southern African region is likely to become generally drier. Over northeastern South Africa, Mozambique and Zimbabwe an increase in extreme rainfall events is plausible. Multi-year El Niño type droughts may plausibly occur from the mid-century ( (onwards) CSIR

Mozambique. General Climate. UNDP Climate Change Country Profiles. C. McSweeney 1, M. New 1,2 and G. Lizcano 1

Mozambique. General Climate. UNDP Climate Change Country Profiles. C. McSweeney 1, M. New 1,2 and G. Lizcano 1 UNDP Climate Change Country Profiles Mozambique C. McSweeney 1, M. New 1,2 and G. Lizcano 1 1. School of Geography and Environment, University of Oxford. 2.Tyndall Centre for Climate Change Research http://country-profiles.geog.ox.ac.uk