1. How will climate change affect Herbertsdale (according to the scientists’ models) Presentation to Herbertsdale community meeting 15 January 2014 Environmental Monitoring Group

2. Project Overview  To see whether (and how) downscaled climate change and hydrological models can support community-led adaptation  Working as interdisciplinary team: scientists, modellers, social-scientists, academics, NGO activists – finding common language, collective learning and mutual support  Team: Umphilo waManzi, EMG, UKZN, UCT (advisory); funded by WRC  Case studies: Umgeni, Berg and other catchments

3. Herbertsdale catchment

4. What do the models say?  RAINFALL: The impact on rainfall is not highly significant.  TEMPERATURE: Herbertsdale is likely to be between 1.5 and 2 degrees hotter by mid-century.  COLD DAYS: There will be significantly fewer days that are cold.  HOT DAYS: The number of hot days is predicted to increase slightly.  STREAMFLOW: the rivers are likely to be slightly fuller.

5. How accurate are these findings? (the science behind the results)  The scientists use mathematical models to project the climate in the future  They use data which can be old (e.g. land use around Herbertsdale)  They have to make decisions about which models to use and what information to put into the models  First: they choose a storyline which helps determine how much greenhouse gas will be in the atmosphere due to human activity  For this study, they picked the IPCC’s A2 scenario (this assumes the world is similar to how it is now…with not much international cooperation and with economic & technical development confined to certain regions)

6. How accurate are these findings? (the science behind the results)  Second: decide how many models to use  They used 10 out of the possible 21 that the IPCC recognises for the A2 scenario  Third: define an area around Herbertsdale to model www.emg.org.za

7. How accurate are these findings? (the science behind the results)  Fourth: use local data from weather stations to inform the models  Limitation: there is only one rain gauge nearby (west of the defined catchment area)  More gauges would give better information for the area and would make errors less likely www.emg.org.za

9. Land use data (based on 2000 survey)

13. What do the models say?  RAINFALL: The impact on rainfall is not highly significant. Most models predict 5-15% increased annual rainfall, although one model (CS2) predicts there could be up to 8.5 more rain days per year, which could mean 8 fewer days to harvest aloe. The timing of rain is unlikely to change significantly (although could be a slight increase in late summer and early spring)  TEMPERATURE: Herbertsdale is likely to be between 1.5 and 2 degrees hotter by mid-century. One of the models predicts an increase of 2.5 to 3C, which would make things pretty hot! And have resultant impacts on soil moisture, water in rivers, etc.

14. What do the models say?  COLD DAYS: There will be significantly fewer days that are cold (all models predict that 7 or fewer days will drop below 5C; versus current average of 17 days)  HOT DAYS: The number of hot days is predicted to increase slightly, although you probably won’t notice them (only one model, IP2, projects a significant increase in the number of days over 35C)  STREAMFLOW: the rivers are likely to be slightly fuller; on average, the models predict approx 20% increase in streamflow

15. What does Herbertsdale need to respond to?  Hotter weather  Fewer cold days  Possibly more frequent and severe droughts and floods ( and, for example, if rain increases, streamflow will increase more significantly)  Markets for produce (e.g. black gold)  Neighbouring farmers responding to climate change (e.g. impact on water, crop choices, jobs, food)  Municipality responding to climate change (e.g. increased water tariffs)  Low carbon economy (less use of fossil fuels such as petrol, diesel, coal for electricity, farming, etc.)  Existing social and economic challenges (e.g. unemployment, low wages, drug abuse, etc.)