One of New Zealand’s pre-eminent scientists and a Nobel prize winner have both backed a growing chorus of concern from the scientific community over the continued use of Overseer after the programme’s negative review released earlier this month.
Sir Peter Gluckman says he first pointed out his concerns about Overseer’s robustness three years ago and they were no different to those raised by Parliamentary Commissioner for the Environment Simon Upton; it was on the commissioner’s prompting that the review was carried out.
The review found Overseer contained some failings that meant it was not fit to be used as a regulatory tool. Particular concerns were expressed about its ability to allow for all nitrogen loss pathways, with the possibility it underestimates nitrogen leaching losses.
“That is, you have taken a tool developed for doing one very specific task in a somewhat obscure way and tried to modify it to do things it could not do, with some obtuse assumptions, not open to peer review,” Gluckman said.
Gluckman says the many millions poured into Overseer over the years had made it difficult to back out of.
“You tend to keep on going, beyond the use by date, when there probably are simpler models out there that could achieve the same for farmers and the environment,” he said.
Overseer is owned by AgResearch (50%) and the NZ Phosphate Company (50%), in turn jointly-owned by Ballance and Ravensdown.
He took Overseer’s commercial structure to task, concerned that it was combined with a lack of peer review or full disclosure on what constituted its “black box” of formula.
The lack of external international peer review of Overseer is a sticking point among all the scientists concerned at the application of Overseer in setting regulatory limits on farmers’ nutrient losses.
“Here we have something that is a public good providing information for all New Zealanders’ environmental benefit and putting constraints on farmers’ businesses, but managed by a private sector entity,” he said.
“I am not sure this is an appropriate model of ownership in the 21st century. It should be as one would expect climate change models to be – available for all to see.”
Martin Manning contributed to the reports of the IPCC, which was awarded the Nobel Peace Prize in 2007.
His work with dynamic climate modelling shared some commonalities with the complex, changeable interactions between water, soils and nutrients.
Manning says he also held concerns about Overseer’s IP confidentiality and lack of journal exposure.
“From my work in climate change, a key performance indicator of funding and work is that it be published, and some of the government funding for Overseer should have been conditional on getting publication and peer reviews,” Manning said.
“The Government now needs to follow up with the review panel and ask ‘how quickly can we come up with something that complements Overseer?’”
He is also concerned over the integration of greenhouse gas calculations into Overseer.
“That simply would not have credibility with the United Nations’ parameters,” he said.
He says far better groundwater monitoring technology was being used in Europe, and the real-time, event-based reporting the Overseer review found lacking was available.
Internationally esteemed mathematician Professor Graeme Wake says Overseer’s static modelling structure failed to allow for the dynamic, changing water-air-soil interactions that occur on farms.
He consulted on the model at an early stage, but says his later offers of expertise in systems modelling were declined. His requests to review Overseer’s workings had also been repeatedly turned down.
Wake says he was ashamed of a science system that had let the country down and farmers were at least owed a tool that was fit for purpose.
Industry concern has been that if Overseer were not used, then ‘top-down’ regulatory impositions would replace it.
But he says there were other models available globally that had proven effective in estimating nutrient flows.
He had personally been involved in the project to clean up the River Thames, which was awarded a top environmental award in 2010 for the restoration success. More recently his modelling work helped restore the Chin River, which runs through Bangkok, Thailand.
“There are models with far better ability to cope with the dynamic cross-flow of nutrients out there, including one known as ModFlow,” Wake said.
Wake is part of a small group of experts working on an Overseer alternative, incorporating the latest modelling algorithms and mathematics, which the group would make available for peer review on completion, possibly within a year.
The group was recently granted $100,000 from AGMARDT through DairyNZ, to continue work on nitrogen management at catchment level.
“We are confident this will do the job Overseer thinks it is doing,” he said.
Government has given Overseer another year to run in its existing form, while recommended actions include a modification of Overseer, or a completely new nutrient management tool.
Both Wake and Gluckman agreed whatever iteration of Overseer was created, it needed to be held in a non-profit organisation, offering open, transparent insights to its workings. Gluckman says he had no aversion to a “user pays” model, per se.
