2nd Drop: Trade-offs between Ecosystem Services?

South's Africa Working for Water Programme

Hi everyone! The first part of this post is just to briefly highlight South Africa's Working for Water programme that was covered in last week's article. 'Ecosystem services, efficiency, sustainability and equity: South Africa's Working for Water programme' by Van Wilgen et al. 1998 provide a very good summary of the impetus, costs, funding and challenges of the programme. 

Overall I do agree with the authors' that the 'Working for Water' programme in South Africa serve as a good example of how the valuation of the ecosystem service of water provision, can serve as a more viable option as compared to conventional approaches in increasing water supply - especially given the cash-strapped economy and poverty situation in South Africa. However I do feel that such valuations of ecosystem services should not neglect the fact that there are trade-offs involved and such payments-for-ecosystem-services systems must be able to justify themselves from a cost-benefit-analysis perspective.

Trade-offs between Ecosystem Services

Which brings me to this second portion of this week's post that highlights the trade-offs that we should take into consideration when we choose particular ecosystem services over others. 'Trade-offs between ecosystem services: Water and Carbon in a biodiversity hotspot', by Chisholm 2010 investigates the potential benefits of afforestation (carbon sequestration and timber production) against the losses to water supply (land-use changes increasing water usage and affecting catchment flow) through a dynamic ecological-economic model applied to Jonkershoek Valley in South Africa. 

Results of the model show that afforestation only appears viable to the forestry industry because the true cost of water used by the plantation are not accounted for by the industry. More importantly the results show largely that afforestation is more commonly associated with overall losses - costs of water supply lost outweigh benefits of C accumulation. The author ends off by discussing the huge amount of variability and uncertainty that still affects the model - given uncertainty in future economic conditions - and thus highlights the need for further research into the development of guidelines as to the conditions under which afforestation of native vegetation will be adopted for carbon sequestration as a viable climate mitigation strategy despite possible trade-offs on water supply.

Here are some reflections that I had:

1) Trade-offs between water and carbon, a choice that is not easily made?

• Payment for ecosystem services systems are not necessarily always synergised harmoniously like Working for Water
• Afforestation scenario described here is a clear eg. - carbon sequestration through plantations measured against lost in water supply
• Where land-use changes are involved, trade-offs will be present and hence choices to sacrifice particular ecosystem services must be made
• But such sacrifices are complicated given socio-economic context of African nations? Ecosystem service of water provision through protection of catchment areas may inhibit land-use changes for economic development purposes (eg. mining, forestry and agriculutre)
• Even with South Africa's payment-for-ecosystem-services scheme of water tariffs for funding may not be sufficient - understate the true value of water that industries pay
• Competing interests from different sectors, eg. forestry industry resisted raising of water-use fees

> Ecosystem services approach may not always be synergised/ complimentary with development and other environmental goals. Identification of clear objectives and considerations of potential trade-offs given socio-economic context must be made for approaches to be effective.

2) Uncertainty with regards to future values of Water and Carbon...

• Demand of water to increase - population increase + per capita consumption increase - and supply to fall...but extent of effect on economic value unclear
• Carbon prices also likely to increase but extent of increase also uncertain...
• Author himself highlight that model is limited given difficulty in incorporating some costs; (1) negative feedbacks due to afforestation raising the value of water; and (2) carbon credits value may be overestimated (afforestation may be ineffective for climate change mitigation because of the lower albedo?)
• there are clearly various other socio-economic and ecological factors that affect the monetary values of ecosystem services

> Ecosystem services approach is closely tied to monetary valuations. But such valuations are complicated by various factors and bogged down by uncertainty! However this does not mean that monetary valuations should be avoided, but instead more research and considerations should be made to ensure valuations are more accurate and representative. This is especially because such monetary valuations of ecosystem services have great potential in motivating policy makers through economic rationality (eg. Working for Water).

THANKS for reading and the comments made! Again, will try to keep my bullet points shorter :X

~Till Next Time~

Jonkershoek Valley, photo by Wimpielmmelman