Risks in the built environment in a changing world Bob Scholes CSIR Natural Resources and Environment 5Feb 2013 SAIA workshop

Question 1: What aspects of the built environment present risks that could be collaboratively addressed? Coastal Flooding due to sea level rise and storms Inland flooding due to increased storm intensity Fires, especially megafires due to climate change Drought, particularly in western southern Africa

Sea level rise Cazenave & Llovel 2010 Contemporary Sea Level Rise. Ann Rev Marine Sci 2, Rahmstorf 2007 Science 316:368 IPCC AR4 Tide gauges Church et al 2004 Satellites Historical sources

Sea level rise, plus changes in storm intensity, combined with tidal dynamics and increased coastal development. CSIR has developed a wave climate model for the entire coastline. Detailed analyses for specific locations require high-resolution bathymetry and altimetry Sea level rise will effect even South Africa

© CSIR A general increase in the frequency of extreme rainfall events, especially the highveld Projected change in extreme rain events over South Africa (>20 mm in 24 hours over an area of 50 km x 50 km) Slide: Francois Engelbrecht, CSIR

Question 2: Practical steps, by whom… coastal flooding BodyTopicAction Surveyor General, SA Navy, private firms Near coast high resolution altimetry and bathymetry Survey areas of infrastructure CSIRSurge mappingApply models to map impact areas Local authoritiesBuilding permitsDo not give permits in at risk areas Insurance industryInsurance premiumsStructure premiums to reflect changing risk Coastal managementCoastal protectionDune, beach and estuary management

Question 2: Practical steps … inland flooding BodyTopicAction CSIRDownscaled climateModels with 8 km resolution for 21 st century Hydrologists: universitis and consultancies Flood return statisticsNew tables and maps for 20 and 100 yr floods DWACatchment managementRestoration, flood control structures, management of flows National Disaster Management, DWA and SAWS Real-time warningModels and observaion system with alerts Planning authoritiesReduction in exposureControl development in flood zone

Question 2 cont: Practical steps…fire BodyTopicAction CSIRAdvanced Fire Information System Realtime warning SAWSFire danger index24 and 48 hour forecasts Working on FireFire avoidanceFuel reduction, firebreaks National Disaster Management Rapid interventionResponse teams for megafires Planning authoritiesReduction in exposureControl buiding in fire- prone areas Fire Protection associationsAvoidance and responseFirebreaks, local response teams

Question 2 cont: Practical steps…drought BodyTopicAction CSIR, UCT-CESAGDownscaled aridity projections Drought probability maps for future climates ARC, SANSA, SAWSEarly warning, affected area verification Greenness and wetness anomalies DAFF, Provincial authorities, Farmers organisations Non-financial insurance avoids damage rather than compensating for it Forage and livestock banking Rapid offtake schemes Insurance industryFinancial insurance for farmers taking appropriate adaptation steps Re-assess risks as they change through the century

End of brief presentation

Human vs Natural Causes

Evidence of a changing world

vs Southern Africa is projected to warm at a higher rate than the global average

CCAM ensemble-average projected change in the Annual frequency of very hot days (>35  C, vs )

..but rainfall futures remain uncertain for our region Ensemble average

Agriculture Climate change effects are negative overall Blignaut et al Dube & Scholes 2011 Scholes livestock: substantial decrease in production Rising temperatures are the key driver, even once rain and CO 2 are factored in But, 1.Large yield gap in Africa (5x) 2.Substantial potential for crop area expansion in in sub-humid Africa (2x)