Antarctica’s Ross Ice Shelf is the world’s largest floating slab of ice: it’s about the size of Spain, and nearly a kilometre thick.
The ocean beneath, roughly the volume of the North Sea, is one of the most important but least understood parts of the climate system.
We are part of the multi-disciplinary Aotearoa New Zealand Ross Ice Shelf programme team, and have melted a hole through hundreds of metres of ice to explore this ocean and the ice shelf’s vulnerability to climate change. Our measurements show that this hidden ocean is warming and freshening – but in ways we weren’t expecting.
All major ice shelves are found around the coast of Antarctica. These massive pieces of ice hold back the land-locked ice sheets that, if freed to melt into the ocean, would raise sea levels and change the face of our world.
An ice shelf is a massive lid of ice that forms when glaciers flow off the land and merge as they float out over the coastal ocean. Shelves lose ice by either breaking off icebergs or by melting from below. We can see big icebergs from satellites – it is the melting that is hidden.
Because the water flowing underneath the Ross Ice Shelf is cold (minus 1.9C), it is called a “cold cavity”. If it warms, the future of the shelf and the ice upstream could change dramatically. Yet this hidden ocean is excluded from all present models of future climate.
There has only been one set of measurements of this ocean, made by an international team in the late 1970s. The team made repeated attempts, using several types of drills, over the course of five years. With this experience and newer, cleaner, technology, we were able to complete our work in a single season.
Our basic understanding is that seawater circulates through the cavity by flowing in at the sea bed as relatively warm, salty water. It eventually finds its way to the shore – except of course this is a shoreline under as much as 800 metres of ice. There it starts melting the shelf from beneath and flows across the shelf underside back towards the open ocean.
The New Zealand team – including hot water drillers, glaciologists, biologists, seismologists, oceanographers – worked from November through to January, supported by tracked vehicles and, when ever the notorious local weather permitted, Twin Otter aircraft.
As with all polar oceanography, getting to the ocean is often the most difficult part. In this case, we faced the complex task of melting a bore hole, only 25 centimetres in diameter, through hundreds of metres of ice.
But once the instruments are lowered more than 300m down the bore hole, it becomes the easiest oceanography in the world. You don’t get seasick and there is little bio-fouling to corrupt measurements. There is, however, plenty of ice that can freeze up your instruments or freeze the hole shut.
Our camp in the middle of the ice shelf served as a base for this science, but everything was moving. The ocean is slowly circulating, perhaps renewing every few years. The ice is moving too, at around 1.6 metres each day where we were camped. The whole plate of ice is shifting under its own weight, stretching inexorably toward the ocean fringe of the shelf where it breaks off as sometimes massive icebergs. The floating plate is also bobbing up and down with the daily tides.
Things also move vertically through the shelf. As the layer stretches toward the front, it thins. But the shelf can also thicken as new snow piles up on top, or as ocean water freezes onto the bottom. Or it might thin where wind scours away surface snow or relatively warm ocean water melts it from below.
When you add it all up, every particle in the shelf is moving. Indeed, our camp was not so far (about 160km) from where Robert Falcon Scott and his two team members were entombed more than a century ago during their return from the South Pole. Their bodies are now making their way down through the ice and out to the coast.
If the ocean beneath the ice warms, what does this mean for the Ross Ice Shelf, the massive ice sheet that it holds back, and future sea level? We took detailed temperature and salinity data to understand how the ocean circulates within the cavity. We can use this data to test and improve computer simulations and to assess if the underside of the ice is melting or actually refreezing and growing.
Our new data indicate an ocean warming compared to the measurements taken during the 1970s, especially deeper down. As well as this, the ocean has become less salty. Both are in keeping with what we know about the open oceans around Antarctica.
We also discovered that the underside of the ice was rather more complex than we thought. It was covered in ice crystals – something we see in sea ice near ice shelves. But there was not a massive layer of crystals as seen in the smaller, but very thick, Amery Ice Shelf.
Instead the underside of the ice held clear signatures of sediment, likely incorporated into the ice as the glaciers forming the shelf separated from the coast centuries earlier. The ice crystals must be temporary.
None of this is included in present models of the climate system. Neither the effect of the warm, saline water draining into the cavity, nor the very cold surface waters flowing out, the ice crystals affecting heat transfer to the ice, or the ocean mixing at the ice fronts.
It is not clear if these hidden waters play a significant role in how the world’s oceans work, but it is certain that they affect the ice shelf above. The longevity of ice shelves and their buttressing of Antarctica’s massive ice sheets is of paramount concern.
Earlier this month, New Zealand’s Supreme Court rejected a proposed land swap that would have flooded conservation land for the construction of the country’s largest irrigation dam.
The court was considering whether the Hawke’s Bay Regional Council’s investment arm could build a dam on 22 hectares of the protected Ruahine Forest Park in exchange for 170 hectares of private farm land. The proposed dam is part of the $900 million Ruataniwha water storage and irrigation scheme.
The New Zealand government’s response to the ruling was to consider a law change to make land swaps easier. Such a move flies in the face of good governance.
The Supreme Court ruling has significant implications for the Ruataniwha dam. In addition, it asserts the importance of permanent protection of high-value conservation land.
The ecological value of the Ruahine Forest Park land was never in question. The conservation land includes indigenous forest, a unique braided river and wetlands that would have been destroyed.
The area is home to a dozen plants and animals that are classified as threatened or at risk. The developer’s ecological assessment acknowledged the destruction of ecologically significant land and water bodies. However, it argued that mitigation and offsetting would ensure that any effects of habitat loss were at an acceptable level.
New Zealand’s environmental legislation states that adverse effects are to be avoided, remedied or mitigated. However, no priority is given to avoiding adverse effects. Government guidance on offsetting does not require outcomes with no net loss.
In Pathways to prosperity, policy analyst Marie Brown argues that offsetting is not always appropriate when the affected biodiversity is vulnerable and irreplaceable.
Recent public concern about declining water quality has provided significant momentum to address pollution and over-allocation to irrigation. Similarly, awareness of New Zealand’s loss of indigenous biodiversity is building.
These issues were highlighted in this year’s OECD Environmental Performance Review and a report by the Parliamentary Commissioner for the Environment on the parlous state of New Zealand’s native birds.
Both issues damage New Zealand’s 100% Pure branding and pose significant risks to tourism and the export food sector. Indigenous ecosystems are a huge draw card to surging numbers of international tourists.
Powerful economic arguments have been put forward by business actors, both internationally and in New Zealand. For example, Pure Advantage supports protection of ecosystems and landscapes. Yet, governance mechanisms are limited.
Since 2009, environmental protection and conservation have increasingly become major battle lines as the National government doggedly pursues its business growth agenda. This favours short-term economic growth over environmental protection.
A key principle behind the Supreme Court decision is that protected conservation land cannot be traded off. It follows a High Court case in which environmental organisations argued unsuccessfully that the transfer of land was unlawful.
However, in August 2016, the Court of Appeal ruled against the Director-General of Conservation’s decision to allow the land transfer. It had been supported on the grounds that there would be a net gain to the conservation estate. The court’s ruling said that the intrinsic values of the protected land had been disregarded.
The Supreme Court has reinforced the importance of the permanent protection status recognised by the Court of Appeal.
In response to the court’s decisions, the government argued that land swaps of protected areas should be allowed. It may seek to amend legislation to facilitate such exchanges.
The Supreme Court made reference to section 2 of the Conservation Act 1987. It defines conservation as “the preservation and protection of natural and historic resources for the purpose of maintaining their intrinsic values, providing for their appreciation and recreational enjoyment by the public, and safeguarding the options of future generations”.
Section 6 of the act states that the Department of Conservation should “promote the benefits to present and future generations of the conservation of natural and historic resources”. As such, the legislation and the department contribute to what is known as “anticipatory governance”.
Anticipatory governance is fundamental to good governance, as Jonathan Boston argues in his recent publication Safeguarding the future: governing in an uncertain world.
It requires protecting long-term public interests. Conservation of our unique ecosystems and landscapes protects their intrinsic values and the services they provide. These include tourism benefits and basic needs such as water, soil and the materials that sustain human life.
The department has correctly recognised that conservation promotes prosperity. However, long-term prosperity is quite different from the short-term exploitation associated with the government’s business growth agenda.
This promotes exploitation in the form of mining on conservation land and increased infrastructure for tourism and other industries, such as the proposed Ruataniwha dam.
Amending the Conservation Act to allow land swaps involves a significant discounting of the future in favour of present day citizens. This is disingenuous and an affront to constitutional democracy. It would weaken one of New Zealand’s few anticipatory governance mechanisms at a time when they are needed more than ever.
During the Abbott government, the often recalcitrant Senate cross bench was thrown a big, juicy bone plainly intended to sweeten their disposition toward government bills which needed their support to pass. The anti- wind farm Senators were outraged with the National Health and Medical Research Council’s (NHMRC) 2015 report on wind farms which found no strong evidence of health effects from turbine exposure. There have been 25 reviews with similar findings published since 2003. The government may have promised these Senators the gift of the office of the National Wind Farm Commissioner which by February 2015 had received just 42 complaints about 12 wind farms, seven of which have not even been built.
In August 2015, the Senate Select Committee on Wind Turbines published its report. The Committee was chaired by Senator John Madigan, an open opponent of wind farms, and consisted of eight members. Six of these had form in savagely criticising wind farms. The content of their final report was therefore utterly predictable, with Labor’s Senator Anne Urquhart’s minority dissenting report shining like a beacon of respect for evidence.
There was no greater display of the naked demonising agenda of the Madigan-aligned group’s anti wind farm show trial than the total absence in their report of any mention of the world’s largest and most important study of the question of whether living near wind farms was harmful to health.
Health Canada’s Wind Turbine Noise and Health study published its preliminary findings on October 30, 2014. Senator Urquhart’s minority report noted that many submissions to the inquiry recognised the great contribution of the Health Canada “Wind Turbine Noise and Health Study” to the body of knowledge on the potential impacts of wind farms on human health. But the 181-page report made no mention of the study.
The study data were collected between May and September 2013 from adults aged 18 to 79 (606 males, 632 females), randomly selected from each household. They lived between 0.25 and 11.22km from wind turbines in two Canadian provinces, Ontario and Prince Edward Island.
In March, the Health Canada study group published its full findings in a series of open-access papers in the Journal of the Acoustical Society of America, the world’s most cited acoustical research journal, and in Sleep, a leading journal in sleep research. Here is a summary of some of its chief findings.
The researchers assessed self-reported sleep quality over the past 30 days using the Pittsburgh Sleep Quality Index and a wrist monitor to record the total sleep time, and the rate of awakening bouts and how long these last, for a total of 3,772 nights.
Averaged over a year, the measured sound of the turbines reached a maximum of 46 dB(A) with an average of 35.6. Forty six decibels is around the sound of a dishwasher operating in a kitchen.
Since January 2012, I have collected and catalogued a remarkable 247 different symptoms and diseases wind farm opponents claim are caused or exacerbated by wind turbines in humans and animals.
But the Health Canada study found that:
Self-reported health effects (e.g., migraines, tinnitus, dizziness, etc.), sleep disturbance, sleep disorders, quality of life, and perceived stress were not related to wind turbine noise levels.
Both self-reported and objectively measured sleep outcomes consistently revealed no apparent pattern or statistically significant relationship to wind turbine noise levels.
But, unsurprisingly, sleep was affected by whether residents had other health conditions (including sleep disorders), their caffeine consumption, and whether they were personally annoyed by blinking lights on the wind turbines.
Sleeping problems affect around 29% of all communities, regardless of whether they are near wind farms or not.
The researchers used a recognised scale to measure self-reported stress (the perceived stress scale – PSS) as well as recording hair cortisol concentrations, resting blood pressure, and heart rate.
However, the majority (77%–89%) of the variance in the perceived stress scale (PSS) scores was unaccounted for by differences in these objective measures. And wind turbine noise exposure had no apparent influence on any of them.
Again, the study concluded that the findings did not support an association between exposure to wind turbines and elevated self-reported or objectively defined measures of stress.
Expressions such as being “hot and bothered” are well understood. When people are annoyed by something in their life, this can lead to the onset of symptoms. Being annoyed is not health problem in itself, but chronic annoyance can have health consequences.
The Health Canada study reported:
Visual and auditory perception of wind turbines as reported by respondents increased significantly with increasing wind turbine noise levels as did high annoyance toward several wind turbine features, including the following: noise, blinking lights, shadow flicker, visual impacts, and vibrations … Beyond annoyance, results do not support an association between exposure to wind turbine noise up to 46 dBA and the evaluated health-related endpoints.
The prevalence of residents reporting that they were very or extremely annoyed by wind turbine noise increased from 2.1% to 13.7% when sound pressure levels were below 30 dB compared to when the noise was between 40–46 dB.
So in summary, those who found the turbines annoying, tended to be those who lived nearer to them.
Even for the most annoying features, more than 86% of residents were not very or extremely annoyed by them.
There is much variation among our families, friends working environments in the way people react to noise. A 2014 review of symptoms related to modern technology (including wind turbines) found those who were more anxious, worried, concerned, or annoyed by a source that they believed to be a health risk more commonly reported symptoms than those without such beliefs.
In this Health Canada study, while proximity to the turbines was statistically significantly associated with annoyance, the relationship was weak. It was better explained by factors such as holding negative views about the visual impact of the turbines (not liking the look of them), being able to the see aircraft warning blinking lights, the perception of vibrations when the turbines were turning and high concern about physical safety. These are all perceptual variables that bothered some but not most.
Less than 10% of the participants derived personal benefit from the turbines (such as income from hosting the turbines). Deriving personal benefit had a statistically significant, although modest relationship to not being annoyed. The authors concluded:
these findings would support initiatives that facilitate direct or indirect personal benefit among participants living within a community in close proximity to wind power projects.
This suggests that strategies such as community sharing of rental incomes, offers of free electricity or home improvement and amenity payments may reduce annoyance.
If a Labor government is elected in July, the future of the ill-conceived Office of the National Wind Farm Commissioner is likely to be vulnerable, as it may well be with the expected departure of several wind farm-obsessed cross bench senators in the double dissolution, should the Coalition be returned.
State governments are increasingly removing wind farm planning barriers and the availability now of the Health Canada health report should drive another large stake through the forces determined to slow the growth of wind energy in Australia.
New Caledonia has created the world’s largest protected area – the Natural Park of the Coral Sea. The link below is to an article that reports on the park.
The link below is to an article reporting on the largest known colony of Eastern Horseshoe Bats in Australia located in the Ourimbah State Forest in New South Wales.
One of the world’s greatest freshwater deltas, the Peace-Athabasca Delta in Canada, is facing a number of threats.
The world’s largest mangrove forest in Bangladesh is under threat from a proposal to build a coal-fired power plant.