Climate change and dairy expansion singled out in 'Environment Aotearoa' report

The area of dairy farmland has increased by 28 per cent in ten years, putting pressure on the soil and increase nitrogen ...
PETER MEECHAM/FAIRFAX MEDIA

The area of dairy farmland has increased by 28 per cent in ten years, putting pressure on the soil and increase nitrogen levels in rivers.

Rapid growth in dairy farmland and surging carbon dioxide levels pose twin threats to New Zealand's environment, an official report finds.

The Environment Aotearoa report, released on Wednesday afternoon, is an independent assessment of New Zealand's environment, covering air, fresh water, land, the sea, atmosphere, and climate.

It finds a 28 per cent surge in the land area used for dairy farming has caused more land to be dangerously trampled down.

The dairy boom has also created a spike in the amount of nutrient leaching into the soil and fresh waterways.

The soil beneath around 80 per cent of dairy farms had been badly damaged by compaction, making land less productive and degrading the quality of waterways.

Nitrogen on land had increased by 29 per cent as a result of livestock and fertiliser since 1990. This had led to a 12 per cent increase in nitrogen levels in rivers - which was due to grow.

"The greatest impact of excessive nitrogen in New Zealand rivers is nuisance slime and algae growth," the report says.

"This growth can reduce oxygen in the water, impede river flows, block irrigation and water supply intakes, and smother riverbed habitats."

About half of all monitored river sites currently had enough nitrogen to trigger nuisance periphyton growth.

"To make an improvement in freshwater is going to take us decades," said Vicky Robertson, Secretary for the Environment.

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Dr Joanne Clapcott, an expert freshwater ecologist who contributed to the report, said the issue was clear.

"The message is not new but it is very clear – New Zealand rivers and streams continue to be negatively impacted by agricultural intensity."

Parliamentary Commissioner for the Environment Jan Wright had only just received the extensive report, and could not properly comment immediately.

She was pleased the "nitrate challenge" was coming to light.

"It's the cows that are adding the nitrogen largely because of the way they urinate. The nitrogen in their urine is very soluble," she said.

"I call this the 'nitrogen challenge' because it's difficult to do much about it."

ANALYSIS: Environment report 'new and independent'

A reliance on overseas markets meant New Zealand was prone to change its land use rapidly.

"Everything we do on land has an environmental impact. Whenever we do a lot of one thing with the land we tend to have that particular environmental problem on a large scale.

"Depending on relative prices our land use can shift quite fast and quite dramatically."

Environment Minister Nick Smith said water quality was a "key issue" for the Government. 

"The Government is of a view that the issue of nutrients on our fresh waterways is a clear area where was have problems. That is why we have a process underway with the land and water forum to further tighten up the rules in that area," he said.

"Intensive farming is going to need to lift its game if New Zealand is going to be able to hang on to its clean green brand."

Yet Smith cautioned against "townies" becoming complacent, warning that urban areas were contributing to freshwater problems too.

Green Party Environment spokeswoman Eugenie Sage said the report showed the Government put too much stock in the dairy industry.

"We have put a lot of bottles in the dairy basket," she said.

"We are destroying our clean green brand, and our integrity in terms of environmental performance, by allowing dairy cow numbers to top six million."

Dairy cows reached 6.7 million in 2014, the report showed, an increase of over 1.5 million since 2004.

Our economy had to diversify, Sage said.

"There is no limit to human ingenuity, to the kind of products we can bring to market with our collective brainpower. There is a limit to the number of cows that we can have on our land."

CLIMATE CHANGE THREAT

Levels of carbon dioxide - the primary greenhouse gas emitted by human activities - had increased in New Zealand by 21 per cent since 1972.

New Zealand's greenhouse gas emissions increased by 42 percent between 1990 and 2013.

Climate change meant oceans had become more acidic and sea levels had risen, which posed a threat to both marine life and coastal communities.

Rising ocean acidity, which is related to global climate change, effects all marine life by decimating the bottom rung of the marine food ladder - plankton.

Plankton and other animals with shells would find it harder to build their shells in a more acidic ocean. Plankton directly or indirectly feed almost all marine animals.

More than a quarter of New Zealand's indigenous marine mammal species face extinction, with particular risks facing Maui's dolphin and the New Zealand sea lion.

Maui's dolphins are now one of the rarest marine mammals in the world, with just 55 individuals over the age of one found.

Of the 92 indigenous seabird species and subspecies that breed in New Zealand, more than a third were threatened with extinction. A further 55 per cent were "at risk" of extinction.

The report also mentions the risk to marine life from oil extraction at sea.

"Extraction operations directly affect seafloor habitats and species, although the effects are localised," it states.

"Sediment plumes produced by the extraction process can have effects over an extensive area, as the suspended sediment spreads. They reduce food availability for some species and smother seafloor species such as corals." 

Wright, while once again noting that she could not comment specifically on the report, said ocean acidity was a serious and long term challenge that New Zealand couldn't solve by itself.

"There's nothing we can do about it except make our contribution to mitigate greenhouse gas emissions along with the rest of the world," she said.

"The world is going to change. Things are going to be very different in 50 years, and change will come faster as time goes on."

"Even if we ceased to emit greenhouse gases overnight, as a globe, the ocean would still expand for years to come - there's a lag effect."

NATIVE LIFE AT RISK OF EXTINCTION

A shrinking indigenous ecosystem was also revealed: indigenous forests were just a third of their pre-human levels and wetlands had reduced by 90 per cent.

Around 80 per cent of resident bird species faced extinction, as did 88 per cent of reptiles and 100 per cent of frog species, largely due to erosion and an increase in urban living.

Of 2378 indigenous vascular plants, 235 were threatened with extinction and 683 were at risk. Seventy-two per cent of indigenous freshwater fish were at risk or threatened.

"Freshwater habitats are directly affected by the way we use land – through discharges of effluent from industrial and urban sources; run-off from farmland; dams and other barriers to migration; and clearance of vegetation along waterways," the report states.

THE GOOD NEWS

The report shows improvements in some areas: over-fishing has decreased sharply, carbon-monoxide emissions from transport have reduced, and a shift to cleaner home heating had seen "significant" improvements in air quality.

"Most New Zealanders enjoy good air quality most of the time," the report states.

"When air quality does reach levels considered unhealthy, this usually happens for limited periods in certain locations. In this way, New Zealand differs from many countries, where air pollution can be a year-round issue in cities and towns."

Between 2009 and 2014, the proportion of fish stocks subject to overfishing decreased from 25 per cent to 14 percent. In 2014, more than 95 per cent of fish caught were from stocks that were not overfished. 

FUTURE REPORTS

The report is the first of its kind, jointly produced by the Environment Ministry and Statistics NZ, using data from hundreds of sources including regional councils and Crown agencies.

"New Zealanders' past and present activities are putting pressures on our environment," Robertson said.

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

As part of the report's release, a website displaying environmental indicators has also been set up.

The report will next be released in 2018, and is expected to be released every three years afterwards.

It does not make recommendations about tackling the issues raised.

 

 - Stuff

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