PIKETBERG, SOUTH AFRICA: Vegetable gardeners in a mountainous nook in the Swartland, two hours’ drive north of Cape Town, are part of a groundbreaking study where scientists are trying to fine-tune global climate and water models into something useful for smallscale farmers. The results have been surprising for farmers and scientists alike.

Right from the start, the vegetable gardeners of the remote Goedverwacht mission village, in the mountains near Piketberg, said they had a good idea of what the greatest threats were to their survival as small farmers: the dense infestation of Port Jackson wattle, an alien invasive tree from Australia with a ravenous appetite for water, which grows prolifically on the banks of their only irrigation source, the Platkloof River. And the high irrigation needs of neighbouring commercial farmers.

So when a team of climate and water modellers zoomed in on their valley, to see how temperature and rainfall patterns would change in future, they returned with surprising findings that affirmed what the farmers had suspected all along.

Yes, temperatures will rise here in the second half of this century (more warmer days, fewer cooler days); rainfall is more difficult to project; land use change will aggravate climate change related water loss from the river catchment through increased evaporation and altered rain patterns. But the more important threats to water supplies and farming here remain over-extraction for irrigation and the thirsty alien trees.

‘This is science confirming local knowledge,’ says Taryn Pereira, researcher with Cape Town-based non-governmental organisation EMG (the Environmental Monitoring Group).

‘Those people in the community who are active and aware , have really valued the fact that they have been brought together as part of a bigger group of experts who confirmed issues which they raised as their main concerns right from the start.’

In a way, this is good news for a group of farmers who operate on the fringe of the formal agricultural market, because it means they have a measure of control over their circumstances: alien invasives can be cleared, if they get funding to cut and poison the thickets; and if they build strong relationships with their neighbours, they can work together to protect the Platkloof’s water so that everyone can benefit.

Pereira explains that these findings emerged from a study where climate and water modellers at the Universities of KwaZulu Natal and Cape Town (UKZN and UCT) are tailoring their ‘coarse’ regional climate models, in order to zoom in on a tighter grid on the map. It is part of a Water Research Commission (WRC) funded project, led by Durban-based NGO Umphilo Wamanzi, to translate climate change and hydrological models for the country’s key catchments into useful information at a local scale to help farmers like these respond appropriately to climate change.

Goedverwacht, which is one of the epicentres of this pilot modelling project, falls on a small river system in the broader Berg River Catchment, which is the main source of water for the City of Cape Town.

Clearing trees, mending fences

The Goedverwacht gardeners produce vegetables, fruit and tend some livestock on land they rent from the historic Moravian Mission. Produce is mostly for their own consumption, although they are exploring some larger commercial opportunities such as the annual ‘Snoek en Patatfees’, a tourism-oriented festival featuring a regionally popular marine fish, and locally grown sweet potatoes.

‘These farmers are extremely vulnerable,’ explains Pereira, who has worked alongside the community throughout the pilot project.

‘This is already a water scarce community, and farmers are completely dependent on water from the Platkloof River for their irrigation. If a commercial farmer decides to build a new dam upriver, what we find is that the farmer will consult with the church head office, based in Cape Town, which may take months before communicating that information to their tenants, the farmer gardeners,’ explains Pereira.

EMG and the Goedverwacht farmers plan to meet later in July to discuss how to begin clearing the alien tree infestation, as well as how to open up a conversation with neighbouring farmers.

‘These gardeners are really concerned that the commercial farms remain viable, because many people here also work on the farms as labourers,’ she says. ‘Grape farming, for instance, might not be viable here in the long term.’

Farmers are worried that if the commercial operators over-extract water from the catchment in the short term, they will eventually sell up and abandon farming. This will leave the Goedverwacht gardeners without water in the short term, and without employment in the future.

Filling in the gaps

After a recent workshop in May, in which the modelling results were presented to the Goedverwacht farmers, the project team were able to identify certain gaps which need filling if these projections are to be useful for farmers on such a small scale:

-       Robust modelling needs to be built on solid historical climate records, usually triangulating data from several weather stations in a region. This modelling could only access data from one weather station, and it’s unclear how close this site is to the community.

-         The pilot work uses a model based on a 10km squared grid, which might still be too ‘coarse’ and ‘granular’ to give Goedverwacht the climatic detail it needs, particularly since the community is situated in a valley, within a mountain range, which might have a more nuanced micro-climate relative to the broader, flatter surrounds which make up most of the footprint of the model.

-       The modelling didn’t look at the likely increase in ‘fire weather’, where hotter, drier conditions in the air and soils, along with faster winds, might mean more frequent fires in the fynbos community (earlier, region-wide modelling has shown this is likely to occur in the Western Cape province). The gardeners are acutely aware of fire risks in the area.

Although these farmers face plenty of challenges – the insecurity that comes with a lack of tenure on the land they farm, difficulty accessing funds for clearing alien invasive plants, the historic power disparity between themselves and their commercial farming neighbours, the inevitability of climate change – the overall message from this research is positive.

‘The message is not ‘don’t worry about climate change’ but rather that the community first has to deal with neighbours and people who are sharing the river, bearing in mind that climate change will add more pressure,’ Pereira says.

It’s about building relationships. And the river can be the shared space that could allow this to happen.