A sweeping audit has revealed an environment under attack from virtually every direction – with climate change also now adding to the pressure.

The Government's just-released Environment Aotearoa 2019 report formed a largely bleak stocktake of our natural heritage, and boiled the picture down to priority areas that needed the most attention.

They ranged from polluted waterways in farming areas and our myriad under-threat species, to our dismally high per-capita emissions and the emerging hand of climate change.

"If we want to protect the things we value, now and for future generations, we need to focus our attention on the choices we can make from here," Secretary for the Environment Vicky Robertson said today.

"The choices we have to make to respond to the issues raised are not always straightforward.

"The economy has been built on our environment, our population continues to grow and climate change is amplifying many current pressures."

Understanding the issues, Robertson said, meant efforts could be focused on the places where the biggest difference could be made.

The Herald singled out four headline figures in the report, which was produced by the Ministry for the Environment and Stats NZ.

75

It's well known that the story of New Zealand's biodiversity is an epic tragedy.

Seventy-five animal and plant species have been driven to extinction since humans arrived here.

Many others now languished close to the brink.

Almost 4,000 of our known native species were currently threatened with - or were at risk of - extinction.

That remarkably included 90 per cent of seabirds, 76 percent of freshwater fish and 84 per cent of reptiles, along with 46 per cent of vascular plants.

The extinction risk had worsened for 86 species in the past 15 years - compared with the conservation status of just 26 species improving in the past 10 years.

More alarming was the welfare of those species that we didn't even know about.

Due to a huge lack of data, only an estimated 20 per cent of New Zealand's species have ever been identified and documented.

"There's an urgent need to document what exists, particularly in the case of insects, microplants such as liverworts, lichens and mosses, and marine life," said the Department of Conservation's chief science adviser, Dr Ken Hughey.

"These species are important because they underpin what makes New Zealand's biodiversity so special, alongside charismatic megafauna like the Maui dolphin and kakapo.

"They're the building blocks that make up our soils, provide food for birds and fish, and enrich habitats – but we don't know the rate of loss because we don't have a complete picture of what's there.

"Getting the data on the remaining 80 per cent of New Zealand species will give us a much better idea of strategies to protect our biodiversity."

Just how many plants and animals had been lost on our watch was difficult to calculate.

What was clearer was the mark humans had left on the landscape.

Many ecosystems had been irrevocably transformed – and what remained had faced wave after wave of introduced pests.

Non-native plant species now outnumber natives here, and stoats, possums, and rats were present on more than 94 per cent of New Zealand land in 2014.

New diseases also posed threats: myrtle rust, a disease that kills native plants like manuka, pohutukawa, and rata, made it to our shores in 2017.

Healthy ecosystems provided important functions: native forests, for example, regulated the climate by storing carbon and prevented erosion.

Natural wetlands also provided important ecosystem services such as purifying water by filtering out nutrients and sediments, regulating water flow during storms, and storing carbon as peat.

When these areas were degraded, and the species within them lost, they became less resilient to more change, which in turn drove further biodiversity decline.

Just how much had we lost?

In the short period between 1996 and 2012, more than 70,000ha of native vegetation vanished, through conversion to pasture, plantation forestry, and urban areas.

It's a dramatic fact that lush green native forests once blanketed 80 per cent of the country: that had since fallen to just a quarter of it.

Ten percent of New Zealand was once also covered by wetlands – 90 percent of these original wetlands have now been drained.

These pollution-filtering kidneys of our landscape have continued to disappear, with at least 1,247ha lost between 2001 and 2016.

By 2012, just over half of our land had been changed to accommodate urban areas or pasture, which now accounted for about 40 per cent of it

Importantly, loss of native vegetation had triggered naturally high rates of erosion and soil loss.

The economic losses associated with soil erosion and landslides were estimated to be at least $250 million to $300 million a year.

Further, increased erosion and soil loss could build up sediment in our rivers, lakes, and coastal environments.

One model of soil erosion used in the report showed how 44 per cent of the soil that entered our rivers each year was likely to come from land covered in pasture.

Plantation forests offered only a temporary benefit for retaining it.

And harvesting by clear-felling exposed and disturbed soils, which could then be vulnerable to erosion for up to six years after harvest.

Meanwhile, the fringes of our urban areas are increasingly being fragmented – broken into smaller land parcels – and sold as lifestyle blocks.

The number of lifestyle blocks has increased sharply in recent decades, with an average of 5,800 new blocks a year since 1998.

One 2013 study found that 35 per cent of Auckland's best land was used as lifestyle blocks.

While urban areas make up a small proportion of our total land - 0.8 per cent, or around 228,000ha, as at 2012 – most areas had developed on this high-quality land, with native forests being cut down and wetlands drained.

The rate of urban sprawl was also spreading: urban land increased by 10 percent between 1996 and 2012, especially around Auckland, Waikato, and Canterbury.

Between 1990 and 2008, 29 percent of new urban areas were on rare, versatile land which often had prime soils ideal for agriculture.

The report noted how the loss of versatile land was happening at the same time as our food production system was under pressure to increase production without increasing its effect on the environment.

This loss could force growers onto more marginal land that was naturally less productive and required more fertiliser.

"It's time to own up to downstream effects of our land use decisions and get tough on industries that undermine our ability help nature thrive," said Forest and Bird's chief executive, Kevin Hague.

"With more than 40 per cent of our land area in exotic pasture, we no longer have a margin of error when it comes to protecting fragments of wetland and native forest.

"We need stronger rules, and we need to put more effort into restoring nature and protecting the margins of our forests and waterways."

82 per cent

The troubled state of our lakes and rivers has been a battleground issue over recent times – one poll out this year found Kiwis were more worried about it than the sky-high cost of living.

The report singled out the impact of farming as an obvious issue.

Computer models estimated that, between 2013 and 2017, about 82 per cent of the river length in pastoral farming areas wasn't safe for swimming.

And over the same period, nearly three quarters of that area was modelled to have nitrogen levels that could affect the growth of sensitive aquatic species.

Compared with catchments dominated by native vegetation, waterways in areas of pastoral farming have markedly higher levels of pollution by excess nutrients like nitrogen, along with sediment and pathogens.

Recent measurements showed that water quality had been improving at some places, yet worsening at others.

The report noted it was difficult to understand exactly what was causing the changes in water quality, partly because water catchments contained a mix of different types of farms and land uses.

"At many of these sites, some variables are at desirable levels or improving, while others are simultaneously at undesirable levels or degrading," explained Niwa's chief freshwater scientist, Dr Scott Larned.

"The importance of variation in rates of improvement or degradation is difficult to convey.

"For example, slowly improving water clarity in a highly turbid lake may be cause for concern rather than celebration, if the lake is likely to remain in a poor condition for many years."

Still, the figures bore a dramatic shift from sheep and beef farming into dairy farming – and most notably in Canterbury, Otago, and Southland – over recent times.

The national dairy herd increased by 70 per cent between 1994 and 2017, while numbers of sheep and beef cattle declined.

The number of cattle per hectare had increased in some parts of the country - a change that made leaching into waterways more likely – and the amount of nitrogen applied in fertiliser had also risen more than six-fold since 1990.

In our cities and towns, waterway pollution was even worse.

Models indicated that 94 per cent of urban waterways had nitrogen levels high enough to affect some aquatic plant species, and weren't safe for swimming, based on campylobacter infection risk.

The report further found it wasn't just pollution that was hurting our freshwater estate, but also extraction.

Although New Zealand had plenty of fresh water, it also recorded the second highest volume of water take per person out of all OECD countries – and that demand had risen markedly.

It had been driven by a near doubling of irrigated agricultural land area between 2002 and 2017, most notably in Canterbury.

Aside from hydroelectricity, most of the consented water allocation was for irrigation, making up just over half of takes in 2013/14, compared with 14 per cent for household consumption.

Taking too much water meant low flows in rivers that offered habitats for fish – and migratory native fish like whitebait and eels were especially at risk.

16 per cent

Out in the oceans, meanwhile, the pressure of commercial fishing had eased in the past decade, and most commercially caught fish came from stocks were considered to be managed sustainably.

But in some cases, it was too late.

By 2017, some 16 per cent of fish stocks in our oceans were assessed as over-fished – and 10 were considered collapsed.

The report highlighted how trawling using large nets or dredges remained the most destructive method of fishing, causing damage to seabed habitats.

The area trawled and the number of tows had decreased over the past 15 to 20 years, but still covered a large area, and some areas had been trawled every year for the past 27 years.

Between 1990 and 2016, trawling occurred over approximately 28 per cent of the seabed where the water depth was less than 200 metres - and 40 per cent where depth was 200 to 400 metres.

Fishing vessels were now larger and more powerful, and used wider trawls and longer lines than when trawling first started more than 100 years ago.

A small number of boats today could have the same impact as a larger fleet would have had in previous decades.

Fishing affected the whole marine ecosystem.

Fish stocks were managed individually and did not account for interactions between different stocks or the broader marine environment.

Because scientists still didn't precisely know the cumulative effects of fishing on the marine environment, it was unclear if the current levels of fishing were sustainable - or where the tipping points were.

Removing fish also changed food chains, affecting species that depended on fish for food, or that were eaten by them.

Not only that, seabed trawling changed the physical structure of the seabed – which we didn't know how long it took to recover – and directly threatened critically endangered species such as the Maui dolphin, of which just an estimated 63 remained.

Added to that was the mounting toll of marine pollution, through sediment, waste and ocean acidification – one of many signs of a fast-warming world.

17.5 tonnes

It's often argued that New Zealand accounts for just a tiny contribution to global emissions – and that's true.

But it's an embarrassing fact that each of us has a shamefully large emissions footprint when compared internationally.

In 2015, the country emitted 17.5 tonnes of carbon dioxide equivalent greenhouse gases per person, which was higher than all but five of 43 industrialised nations.

Our gross greenhouse gas emissions had increased by 20 per cent since 1990, but had been relatively steady in the past decade, despite increases in population and GDP.

This meant our emissions per person were lower now than 10 years ago.

Similarly, our emissions per unit of gross domestic product since 1990 are 43 per cent lower – yet still high internationally, and the fourth highest in the OECD in 2016.

Our larger cities tended to have high levels of black carbon, one of the most important contributors to global warming.

The report noted our high per-person emissions were partly due to the large proportion of methane and nitrous oxide from agriculture.

These gases warmed our atmosphere more strongly than carbon dioxide (CO2), and increased our per-person CO2-equivalent greenhouse gas emissions.

Road vehicles were the main source of CO2 emissions, and New Zealand still had the highest rate of car ownership in the OECD.

In the background, the rate at which climate change was affecting our environment was unprecedented.

Already, New Zealand had experienced higher land and sea temperature; up to 22cm of sea level rise in the past century; ocean acidification; and melting that had seen our glaciers lose a quarter of their ice in just 40 years.

In some parts of the country, climate change was manifesting with drier soils, fewer frost days and shifted rain patterns.

While most places had seen no change in extreme rainfall since 1960, studies indicated that because of climate change, some flood and drought events were worse than they would have been or had a higher likelihood of happening.

These effects are only expected to intensify over coming decades, with wide-ranging consequences.

"Years of procrastination and denial mean that our per capita impacts are among the highest in the world," Hague said.

"We need to take action on this immediately, and we need a strong Zero Carbon Bill."

'We must transform the way we live'

Climate Change Minister James Shaw was all too aware of that need.

"The introduction of climate change legislation, establishing an independent climate change commission to guide emissions reductions, and the just transition to a low emissions economy are vital, as the evidence in this report shows," he said.

"An important message here is that all of the issues described in this report are made worse, in some way, by climate change and this Government isn't ignoring that."

Environment Minister David Parker said he was unsurprised at what the report told us.

"We've known for years about the pollution and damage we've been causing to our oceans and freshwater, climate and biodiversity," he said.

The Government had work underway that would directly address many of the issues raised, he said.

Last year it released its Essential Freshwater plan to achieve a noticeable improvement in water quality in five years.

"That will take steps to stop further degradation of our waterways," he said.

"They include controls on further intensification and on activities with a significant risk of contaminating waterways through pollutant losses, such as intensive winter grazing on forage crops."

The new rules would also address the loss of our wetlands.

"New Zealanders are facing up to the reality and taking action, be it community groups, farmers groups or the school students who took to the streets over climate change," Parker said.

"This Government is delivering on public expectations that we will protect and restore our environment for this and future generations."

But Kevin Hague pointed to many more bold actions that were urgently needed if New Zealand wanted to stem the damage wrought on its backyard.

"Within the next year, among other things, we need a forceful Biodiversity Strategy, an effective Zero Carbon Bill, good National Policy Statements on Freshwater Management and Indigenous Biodiversity, more funding for the Department of Conservation, and strong environmental policies from all of our political parties," he said.

"We must transform the way we live in our environment; we also need to stop supporting industries that undermine this change."

"Forest & Bird faces these battles every day: more water being taken out of the already compromised Rangitata River, delays to getting cameras on fishing boats, or a coal mine proposed at the site of the largest known population of a rare and beautiful forest butterfly.

"Ultimately a thriving natural world can help us all: by providing clean water, protecting us from climate change impacts, and allowing our children a chance to see the wonderfully unique creatures – such as geckos, kaka, or dolphins – that call New Zealand home."