WHILE the title, Empirical measurement of the impact of climate change – correcting for measurement error in precipitation and understanding the incidence of impacts, of Dr Kendon Bell’s research project is daunting the intent is relatively straightforward.
He wants to know why climate impact measurements show rainfall changes having little effect on agriculture.
“But there is a contradiction there between those numbers, what they indicate and the way farmers may speak about the impact of a drought in any given year.
“It is as if the impact has been diluted and the goal of the project is to sort out how we measure precipitation, record it and extrapolate it then determine its true effects on agriculture.”
He is working in climate econometrics, an emerging field combining the history of weather, economic and social outcomes with climate forecasts to estimate future damage from climate change.
“The work gives me a chance over the two-year grant period to combine economics and big data to tackle a key question for society and how it affects people.”
He suspects part of the reason climate models show rainfall having only a small impact on agriculture might be simply down to how rainfall is measured.
“It could be we are using gauge measurements in certain places and extrapolate it when it is not entirely accurate to start with. This is particularly so when conditions are dry and only a small amount of rainfall is experienced. Then gauges can do a poor job of picking up precipitation and even lose it to evaporation.”
In addition, the impacts of dry conditions can vary significantly in different locations in a region.
A typical example is in Waikato where drought north of Hamilton can go unnoticed south of Hamilton.
“So those differences in districts can really dilute the overall picture of precipitation’s impact.”
Bell said climate changes outcomes for a small, temperate group of islands like New Zealand might not prove entirely negative in a uniform way across the country.
“We may see things warmer further south and see that as an improvement over winter months.
“We could have to balance that against northern regions that may also have warmer winters but, for them, that may be outweighed by significantly hotter summers.
“The big challenge is adding together the negative effects and the positive to see how they weigh up.”
He expects his task will be made significantly easier not only by having two years of funding but also having access to a network of high-performance computers and support systems through the NZ eScience Infrastructure.
The second half of the project involves an even deeper leap into data as Bell tries to evaluate where prices will move to for key products in an environment affected by climate change.
“It will be a case of trying to determine who benefits and who pays.
“For example, if whole milk prices go through the roof due to lost production overseas, farmers here would benefit but the burden will fall on consumers and at what point will they have to spend less elsewhere due to that?”
The tough part will be determining how much prices will move as products move through the supply chain.
“Farmgate prices are pretty transparent.
“As you move from the processor to the retailer, trying to determine just how much they will pass on the cost rises that may occur can be difficult.”
Perhaps the most recent source for comparison is the food price spikes experienced in 2007.
Price rises on staples including corn in Mexico and onions in India prompted food riots unseen for years.
“But these were spikes whereas under climate change conditions people are likely to be storing more, possibly softening the increase in price and supply shortages.”
He intends to follow weather-induced milk-price shocks through different stages of supply given milk’s relatively short supply chain, perishability and simple inputs that lend it well to modelling.
At the end of his work Bell is confident he can present farmers with a map showing the expected changes in production for a particular commodity for each region under certain climatic conditions, giving farmers a tool to decide for themselves whether a change in commodity or farming method is required.
“Pricing is trickier.
“The final output may be for a given global change in a product (say dairy), how much of the price change will be borne by consumer, processor, retailer and farmer.”
Growing up in Putaruru with dairy farming families as friends Bell appreciates his work steps beyond arcane algorithms and formulations with outcomes that will have real effects on farming communities.
“Scientists tell us climate change effects are here and there is more to come over coming decades.
“This is about trying to understand what the impacts will be, who will benefit and who will suffer and improving the methods in understanding them.”
