Twin threats to our pristine environment
RAPID growth in dairy farmland and surging carbon dioxide levels pose twin threats to the environment, an official report finds.
The Environment Aotearoa report, released yesterday, 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 about 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.’’
‘‘To make an improvement in freshwater is going to take us decades,’’ said Vicky Robertson, Secretary for the Environment.
Dr Joanne Clapcott, an expert freshwater ecologist who contributed to the report, said the issue was clear – ‘‘rivers and streams continue to be negatively impacted by agricultural intensity.’’
Parliamentary Commissioner for the Environment Jan Wright 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.’’
A reliance on overseas markets meant New Zealand was prone to change its land use rapidly.
Environment Minister Nick Smith said water quality was a ‘‘key issue’’ for the Government.
‘‘That is why we have a process under way 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 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 spokeswoman Eugenie Sage said the report showed the Government put too much stock in the dairy industry and the economy had to diversify.
CLIMATE CHANGE THREAT
Levels of carbon dioxide – the primary greenhouse gas emitted by human activities – had increased by 21 per cent since 1972.
New Zealand’s greenhouse gas emissions increased by 42 per cent 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, affects 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 the Maui’s dolphin and the New Zealand sea lion.
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.’’
Wright said ocean acidity was a serious and long-term challenge that New Zealand could not 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.’’
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.
About 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, the report says.
‘‘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 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.’’
Between 2009 and 2014, the proportion of fish stocks subject to overfishing decreased from 25 percent to 14 per cent.
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.
The next report will be made public in 2018.
They do not make recommendations about tackling the issues raised.