Adapting agriculture to a changing climate

This is a guest post by Dr Gavin Kenny ((Gavin has a PhD in agricultural meteorology, managed a European Union climate change project at Oxford University in the early 1990s, followed by eight years with a research group at University of Waikato. He has worked independently since 2001.)), a New Zealand scientist who has worked on agricultural adaptation to climate change in NZ and world wide. He has a very interesting and informed perspective on the sorts of things NZ agriculture should be doing to address climate change as it happens — exactly the sort of conversation we need to have on this big issue. The article first appeared in the agriculture section at Stuff.co.nz last week.

For more than 20 years I have worked professionally on the “what ifs” of climate change, focused mostly on what it might mean for agriculture. I’ve done this work in New Zealand, Europe, the Pacific Islands and Asia. During that time I have experienced the progression from the hypothetical to real-world responses. Climate change, particularly as experienced through more frequent drought and flood events, is increasingly influencing what farmers are doing in many countries. It is not clear whether this is yet the case in New Zealand, but I suspect so.

With a record summer drought just behind us, and with negative and positive effects that will continue to unfold for farmers, it is relevant to ask: What if we get more frequent and intense droughts in the future? How might farming change and how might those changes affect wider society?

To help guide our thinking and acting for the future it is instructive to first look to the past, not just in New Zealand but to other societies and civilisations that have entered periods of more frequent and intense droughts.

In his book The Long Summer: How Climate Changed Civilisation, Brian Fagan explores the impact of climate shifts, including drought, on civilisations over the last 15,000 years. He writes:

“In our efforts to cushion ourselves against smaller, more frequent climate stresses, we have consistently made ourselves more vulnerable to rarer but larger catastrophes.”

The story of the city of Tiwanaku is a good example. Over a period of 500 years Tiwanaku thrived near the shores of Lake Titicaca in what is now Bolivia. The city was supported by agricultural intensification that was strongly reliant on water.

The onset of a climatic shift about AD1100 changed everything. Annual rainfall declined by 10 to 15 per cent over a prolonged period and Tiwanaku crossed a critical threshold of vulnerability. Fagan explains:

“The ability of the Tiwanaku state to adjust to the great drought was limited culturally by centuries of rapid population growth underwritten by the remarkable productivity of the raised fields. […] Tiwanaku’s economy was entirely dependent on this single agricultural technology, which in turn depended on abundant water. When the water failed, the entire system collapsed.”

Focusing back on present-day New Zealand we have seen a strong move towards intensification of farming over the last 20 years. Two obvious examples of this intensification are the increased focus on irrigation and the huge increase in use of urea fertiliser. The lesson from Tiwanaku is that it would be unwise to simply put our faith, and a huge amount of debt for infrastructure development, in more large irrigation schemes.

This is not a matter of cockies ((NZ slang for farmers.)) versus townies. Agricultural intensification in New Zealand has been fuelled by our collective demand for consumer goods. We can’t criticise the negative things we see with farming without looking at our own behaviour.

And that gets to the crux of what climate change requires of us all: behaviour change. Simply put, we’re increasingly living beyond our means and the capacity of our land and water resources to sustain our wants.

What’s the alternative then? Since 2001 I have worked on documenting positive things farmers are doing that are relevant in terms of building resilience to climate change.

This includes increasing numbers, still a minority, who are shifting to biological soil management; changes in pasture species and management with a focus on longer covers (not grazing the grass so hard) and greater rooting depth; changes in stock policies aimed at greater flexibility; a focus on greater soil moisture retention; fencing of riparian areas; on-farm water storage; planting trees for multiple benefits; fencing remnant native bush and putting them into QEII Trust covenants.

We already have the ingredients for smart, resilient, farming systems. The vision I have for farming in New Zealand is consistent with Colin Tudge’s Campaign for Real Farming. In a New Zealand context this would involve developing a “Food First” policy to ensure that the basic food needs of all within New Zealand are met for now and for a future with climate change. We then export the surplus.

This would be founded on low carbon farming systems that are a functional part of, and working within the natural constraints of, local environments. There is a lot of unrealised ecological potential in this regard, which is strongly linked to unrealised economic potential.

To develop such a future we’ll all need to look at changing our behaviour. In Colin Tudge’s words “We are talking about the difference between a world that could endure effectively forever, in peace and conviviality, and one that could be in dire straits within a few decades.”