NZ's 'clean environment' under pressure

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The study found that water quality in rivers that run through intensively used land has worsened....
The study found that water quality in rivers that run through intensively used land has worsened. Photo ODT

A major new report has shown how New Zealand's "clean green" environment is under pressure on all fronts - particularly from climate change and intensive land use.

Nick Smith
Nick Smith

The Environment Aotearoa 2015 report - jointly released by Statistics New Zealand and Ministry for the Environment today and drawing on data from hundreds of sources - makes a sweeping health check of our green and blue backyard.

It found that the amount of carbon dioxide in our atmosphere has increased; diversity and conservation status of some native species have declined; water quality in rivers that run through intensively used land has worsened; and more than three quarters of soils under dairy farming are now badly affected by compaction.

"New Zealanders' past and present activities are putting pressures on our environment," Secretary for the Environment Vicky Robertson said.

"These pressures are growing as our population increases, our economy develops, and our lifestyles change."

Environment Minister Nick Smith, who had no input or influence in the report, said it showed the key challenge areas were freshwater, climate change and biodiversity.

New Zealand was making good progress in reducing air pollution that caused urban smog and many premature deaths, a

nd our fisheries were being more sustainably managed with fewer stocks overfished and significant reductions in seabird bycatch, Dr Smith said today.

The report on freshwater was, however, a "mixed bag", he said, and varied significantly around the country.

While water clarity and pollution from ammonia-nitrogen was improving, the trends for total nitrogen and dissolved phosphate were negative.

"While the report finds that 96 percent of monitored freshwater sites are suitable for wading and boating, it does not report on swimming water quality. I am advised this is because the data is inconsistent and not nationally comparable. This is an area on which we will need to improve the data."

The report also showed New Zealand needed to "step up its efforts" on greenhouse emissions and climate change, he said.

The major threat to the country's biodiversity remained from introduced pests, and the while the Government had increased areas were pests were controlled, the reality was that too many of our native species were in decline, Dr Smith said.

The Green Party responded to the report with criticism of what it called a "hands-off" approach by the Government, and stated it should trigger "urgent action" to protect indigenous wildlife, rivers, and seas.

"What we need to see from the Government is a commitment to stop subsidising dairy intensification and to strengthen water standards so that it's safe for people and wildlife to swim in our rivers," environment spokesperson Eugenie Sage said.

"We need a much greater investment in pest control on conservation lands and beyond. We also want to see a commitment to establishing effective deep sea marine protected areas and ocean sanctuaries to protect marine habitats, and a National Policy Statement for Freshwater Management that actually ensures the water is fresh."

Parliamentary Commissioner for the Environment Jan Wright welcomed the report, and said she would be publishing a commentary once she had examined it. "Environmental reporting is important for diagnosing the health of our environment and helping us to prioritise action."

Dr Wright noted the Environmental Reporting Act, passed last month, required the production of environmental reports at regular intervals - and at arm's length from the Government.

Water quality: Farming increases nitrogen run-off

The report found that while water quality was very good in areas with indigenous vegetation and less intensive use of land, it was a different story in agricultural and urban areas where there was reduced water clarity and aquatic insect life, and higher levels of nutrients and harmful E.coli bacteria.

The greatest impact of excessive nutrients in rivers was nuisance slime and algae (periphyton) growth, which could impede river flows, block irrigation and water supply intakes, and smother riverbed habitats.

Between 1990 and 2012, the estimated amount of nitrogen that leached into soil from agriculture increased 29 percent, which was mainly due to increases in dairy cattle numbers and nitrogen fertiliser.

Once in the soil, excess nitrogen traveled through soil and rock layers, ending up in groundwater, rivers, and lakes.

Between 1989 and 2013, total nitrogen levels in rivers increased 12 percent, with 60 percent of monitored sites showing statistically significant increases.

About 49 percent of monitored river sites have enough nitrogen to trigger nuisance periphyton growth, as long as there was enough sunlight, phosphorus, and a lack of flood events for algae to bloom.

Phosphorus also triggered nuisance algae growth, and about 32 percent of monitored sites had enough phosphorus to trigger this growth.

High levels of nitrogen could also be harmful to fish, although less than 1 percent of monitored river sites had nitrogen levels high enough to affect the growth of multiple fish species.

Water clarity improved at two-thirds of monitored sites between 1989 and 2013, while E.coli levels were higher in urban and pastoral areas but met acceptable standards for wading and boating at 98 percent of monitored sites.

Marine environment: Climate change the key threat

The most serious long-term pressures on our vast and incredibly diverse marine environment were likely to be caused by climate change, the report found.

Coastal sea levels and long-term sea-surface temperatures around New Zealand had risen over the last century, and our oceans were now more acidic than when measurements were first taken in 1998.

Eight of our 30 indigenous marine mammal species are threatened with extinction, and the extinction risk of one of these - the New Zealand sea lion - has increased in recent years.

The Maui's dolphin was now one of the rarest marine mammals in the world, with an estimated 55 individuals over a year old remaining.

Of the 92 indigenous seabird species and subspecies that breed in New Zealand, 35 percent were threatened with extinction and a further 55 percent were at risk of extinction.

The risk of extinction had also increased for seven seabird species in recent years.

Between 2009 and 2014, the proportion of fish stocks subject to overfishing decreased from 25 percent to 14 percent.

In 2014, more than 95 percent of fish caught were from stocks that are not overfished.

Air and atmosphere: More carbon dioxide, less carbon monoxide

The report found burning wood and coal for home heating was the primary source of pollutants that caused most concern, as it contributed 58 percent to annual emissions of human-made particulate matter in our air.

This was a problem mainly in winter, in places where households use wood or coal to keep their homes warm.

But air quality showed a significant improvement since 2006, driven mainly by the shift to cleaner home heating.

Between 2001 and 2013, estimated emissions for five key pollutants from road vehicles fell between 26 and 52 percent, due to improvements to fuel, and stricter emission limits on new vehicles.

In 2012, an estimated 1000 premature deaths were associated with particulate matter in our air, 14 percent fewer than in 2006.

In the wider atmosphere, meanwhile, the biggest driver of change was the increase in global greenhouse gases.

Global net emissions of greenhouse gases rose 33 percent since 1990, and between 1990 and 2011, New Zealand emitted around 0.1 percent of global emissions.

New Zealand's emissions of greenhouse gases increased 42 percent between 1990 and 2013.

Concentrations of carbon dioxide - the greenhouse gas that had the greatest impact over the long term - have increased 21 percent since 1972.

New Zealand's temperature increased around 0.9C in the past 100 years, which was "almost certainly" due to the increase in greenhouse gases in the atmosphere, the report found.

Our exposure to high ultraviolet light levels were also part of the reason our rates of skin cancer (melanoma) incidence were among the highest in the world.

Land and nature: Erosion and pests among the biggest problems

While the extent of agricultural land has not changed substantially since 1996, its use has become more intensive in many regions.

The most critical issue affecting our land was erosion caused by human activity, particularly in the north and east of the North Island.

This reduced the productivity of the land and affects water quality, because it added sediment and nutrients to waterways.

Another big issue facing our land is compaction, which ocurred when soil was compressed, reducing the air pockets between soil particles, and making it harder for plants to grow.

Over half the soils measured under dry stock - animals farmed for dairy, meat, wool, and velvet - and nearly 80 percent of soils under dairy farming were affected by compaction, which reduced the productivity of land.

Pests also remained a serious threat to our indigenous animals, plants, and habitats. Possums, rats, and stoats, the most widespread of our pests, were found across at least 94 percent of the country.

The report noted how our land had undergone extensive change since human occupation 700 to 800 years ago, and particularly since European settlement in the 19th century.

Today, agricultural and horticultural land occupied nearly 42 percent of New Zealand, while plantation forestry covered a further 7.5 percent.

Indigenous forest covered about one-quarter of the country, concentrated mainly in upland and mountainous areas, and wetlands had reduced to just 10 percent of their original extent.

*The independently-produced report was produced in the spirit of the recently-passed Environmental Reporting Act, and is the first of its kind since 2007. The next report - about fresh water - will be released next year.


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