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Hikers approaching Franz Josef Glacier, Westland. The glacier was still advancing until 2008, but since then has entered a very rapid phase of retreat – as are most of New Zealand’s other glaciers. Photo: Getty Images

ScienceJanuary 29, 2019

West Coast council shows that on climate change, facts often aren’t enough

big big mountains with blue sky and a small river of ice between cliffs with people in the foreground
Hikers approaching Franz Josef Glacier, Westland. The glacier was still advancing until 2008, but since then has entered a very rapid phase of retreat – as are most of New Zealand’s other glaciers. Photo: Getty Images

The astonishing decision by the West Coast Regional Council to refuse to back major climate change legislation shows there are still major communication hurdles to be overcome, even when the science is settled.

One of the first things to understand about the science of climate change is that it’s actually quite simple. The projected effects might be unpredictable and complicated, but the causes can be summed up in a few basic bullet points. In fact, it was done so by climate scientist James Renwick on Twitter today:

1. Greenhouse gases absorb heat.

2. More greenhouse gases = more warming.

The issue has blown up after the West Coast Regional Council announced that they would not be supporting the Zero Carbon Bill – the government’s flagship climate change legislation aimed at reducing emissions. The Council made a submission that said “the evidence proving anthropogenic climate change must be presented and proven beyond reasonable doubt”.

Hasn’t that already happened? The recent Intergovernmental Panel on Climate Change report for policymakers put it bluntly: “Impacts on natural and human systems from global warming have already been observed (high confidence). Many land and ocean ecosystems and some of the services they provide have already changed due to global warming (high confidence).” Human activities are listed as the cause. It’s not an overly complicated document, but it is pretty dry. And that could be part of the problem, according to Dr Jess Berentson-Shaw, a researcher and co-director of think tank The Workshop.

“I think it’s important for scientists to understand that just because we find the evidence compelling, and then talk about it, does not automatically mean that’s compelling to everyone else,” she says. “There is a really big gap between the general public’s understanding of this stuff, and experts.”

She adds that the way scientists often talk about climate change can be in and of itself unscientific. “We pay very little attention to the the science of making those facts compelling to the people who need to act on those facts. And it’s not really the scientist’s fault in that sense – that’s a whole different level of expertise that isn’t really well understood or recognised.” She adds that research she has undertaken shows that – counter to the protestations of the West Coast Regional Council – more science and more evidence probably won’t make much of a difference.

So how can it be made more understandable? It’s about finding shared values, says Berentson-Shaw. For climate change, one value that could bridge the gap could be wanting to help future generations. That’s something fundamental to pretty much all political ideologies – that you want your children to grow up in a better world than you did. “Look, it’s really hard to do, and I have to say half the time I fail at it. But starting from a position of arguing the facts immediately gets people into a position of not wanting to hear the evidence. You kind of have to find a way to lower the barrier to do that, and one way to do that is to seek out those common values.”

Sometimes those values may be more easily expressed in economic terms than environmental terms. According to Infometrics, the economy of the West Coast is disproportionally dependent on mining and other primary industries, relative to the rest of the country. The region is on struggle street, with the most recent data showing a shrinking economy, and falling numbers of jobs. As James Renwick puts it, even though the West Coast’s economic fears of emissions reductions have to be taken seriously, “the sea level continuing to rise – that’s going to be more damaging to the local economy than any change in how the economy works there.”

But part of the problem might be simply that those in charge don’t want to listen. Last year, experts from NIWA and the Ministry for the Environment visited the Regional Council, to discuss the effects that climate change-caused sea level rises will have on the area. James Renwick has sent an email to the Regional Council offering to come to them to discuss the issue. He’s hopeful they’ll take him up on it, but believes “they’ve heard the story, and it’s not a matter of not understanding it or needing it to be explained in words of one syllable. But I don’t really think it’s about not understanding, it’s about resistance and not wanting to change.”

But to take that as evidence that Coasters don’t care about climate change would also be wrong. The counter-argument was put in 2017 by Megan Rich, a school principal in the town of Granity. She noted that the school used to have a tennis court and a pool, but both have been destroyed by rising seas. To the north, Buller District’s elected representatives are grappling with the idea that Westport might need to be moved further inland. And political scientist Dr Bronwyn Hayward says she takes students to talk to people on the West Coast every year, and the people are aware of the effects of climate change. “It’s a tough situation they’re in, and listening matters rather than just writing off their objections as being those of rednecks.”

According to Radio NZ’s reporting, only councillor Stuart Challenger opposed the submission. In contrast, councillor Allan Birchfield described climate change as a “fraud.” Jess Berentson-Shaw says for scientists and communicators, people like Mr Birchfield are probably a lost cause. But that doesn’t mean that there’s no point in talking about the issue generally. “Think about it – are you actually going persuade this particular person? Is it worth expending your energy? Or is it more worth trying to persuade people who don’t yet have a particular view on it?” For voters around the country who do want more comprehensive action on climate change, those questions will be in sharp relief when elections roll around later in the year.

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A study of drinking water sourced from groundwater in areas of intensive farming and horticulture found nitrate levels are already high and rising. from www.shutterstock.com, CC BY-ND
A study of drinking water sourced from groundwater in areas of intensive farming and horticulture found nitrate levels are already high and rising. from www.shutterstock.com, CC BY-ND

ScienceJanuary 28, 2019

Could New Zealand’s drinking water be causing cancer?

A study of drinking water sourced from groundwater in areas of intensive farming and horticulture found nitrate levels are already high and rising. from www.shutterstock.com, CC BY-ND
A study of drinking water sourced from groundwater in areas of intensive farming and horticulture found nitrate levels are already high and rising. from www.shutterstock.com, CC BY-ND

A study showing a link between nitrate levels in drinking water and rates of bowel cancer should concern people living in areas of New Zealand where nitrates are high, write Mike Joy and Michael Baker.

Last year, a Danish study reported a link between nitrate in drinking water and the risk of developing colorectal (bowel) cancer. This finding could have important implications for New Zealanders.

New Zealand has one of the highest bowel cancer rates in the world. Recent data show also that drinking water supplies in some parts of New Zealand have nitrate levels more than three times higher than the threshold level for colorectal cancer risk identified in the Danish study.

This study and other research raise an important question about the contribution nitrate exposure through drinking water may be making to New Zealand’s high rates of bowel cancer.

Health implications of nitrates in drinking water

Nitrate fertiliser is added to pasture and crops to accelerate plant growth. Much of it enters waterways either directly with rain and irrigation or through animal urine.

The Danish study, published in the International Journal of Cancer, was extensive both in number of participants and length of follow-up. It included 2.7 million people over 23 years and monitored their individual nitrate exposure levels and colorectal cancer rates.

The findings confirmed widely held suspicions that long-term exposure to nitrate may be linked to cancer risk. The investigators propose that the risk results from nitrate converting into a carcinogenic compound (N-nitroso) after ingestion.

The research found a statistically significant increase in colorectal cancer risk at 0.87ppm (parts per million) of nitrate-nitrogen in drinking water. There was a 15% increase in risk at levels over 2.1ppm, compared with those who have the least exposure.

One key implication is that the current nitrate standard for drinking water used in most countries, including New Zealand, is probably too high.

International nitrate standards

The cancer risk level (0.87ppm) identified in the study is less than a tenth of the current maximum allowable value (MAV) of nitrate-nitrogen of 11.3ppm (equivalent to 50ppm of nitrate). This level has been in use in many countries for decades and comes from the World Health Organisation’s limit. It is based on the risk of “blue baby syndrome” (infantile methaemoglobinaemia, a condition that reduces the ability of red blood cells to release oxygen to tissues) – but not the risk of cancer.

Rates of bowel cancer vary across New Zealand, with the highest incidence in South Canterbury, with an age-standardised rate of 86.5 cases per 100,000 people. Bowel cancer is the second-highest cause of cancer death in New Zealand and each year around 3,000 people are diagnosed and 1,200 die of the disease.

A recent epidemiological review estimated the contribution of a range of modifiable “lifestyle” risk factors to colorectal cancer in New Zealand. In order of importance, these factors are obesity, alcohol, physical inactivity, smoking and consumption of red meat and processed meat. It would be useful to conduct more research to see if nitrate exposure in drinking water should be added to this list.

This map shows the nitrate-nitrogen trends at monitored sites. The Canterbury region, on the east coast of the South Island, shows that groundwater quality has worsened.
Ministry for the Environment, Stats NZ, CC BY-ND

A recent Fish and Game New Zealand investigation of drinking water supplies in the Canterbury region found that nitrate levels in drinking water sourced from groundwater in areas of intensive farming and horticulture are already high and rising. The findings are consistent with data from the regional council Environment Canterbury. The latest groundwater report showed that half of the wells they monitor have values greater than 3ppm nitrate-nitrogen, more than three times the Danish study’s trigger level for colorectal cancer risk.

Christchurch City Council data show that of 420 samples collected during five years from 2011 to 2016, 40% exceeded 0.87ppm.

Impact on ecosystems

When nitrate enters waterways, it accelerates algae growth. Freshwater scientists have long been pushing for nitrate limits to curtail algal proliferation, but restrictions have been slow and in some regions non-existent. An important coincidence is that the Australian and New Zealand guideline for healthy aquatic ecosystems for nitrate is at 0.7mg/l nitrate-nitrogen, close to the level required to stay under the colorectal cancer risk value found in the Danish study.

The Canterbury region exemplifies the problems resulting from the failure of central and local government policy in New Zealand to protect both ground and surface water. These failures cannot be blamed on a lack of awareness as these outcomes were predicted decades ago. For example, in 1986 the Ministry of Works predicted the nitrate contamination we now see as a consequence of regional irrigation schemes. It made it clear that alternative drinking water supplies would have to be found for Canterbury residents.

Apart from health and ecological concerns, another worry is that public fears about drinking water safety will prove a boon for water bottling companies, which have free access to New Zealand’s cleanest water.

While many New Zealanders face significant and increasing costs for water treatment, water bottlers pay virtually nothing. The only cost, apart from bottling costs, is a one-off 35-year regional council consent fee. This anomaly highlights the urgent need for government to put tougher limits on nitrate loss and face up to dealing with water ownership issues in New Zealand.

In conclusion, surface water in many parts of New Zealand is highly contaminated with nitrates as a result of intensified farming. These elevated levels are undoubtedly damaging freshwater ecosystems and biodiversity, and may also be harming human health.

At the very least, public health authorities need to conduct a systematic survey to assess current nitrate levels in New Zealand drinking waters, including those that are not part of the routinely monitored networked system. This information could then be used to provide a quantitative estimate of the colorectal cancer burden in New Zealand that can be attributed to this hazard.The Conversation

Mike Joy is a senior researcher at the Institute for Governance and Policy Studies at Victoria University of Wellington. Michael Baker is a professor of public health at Otago University.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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