We always cross our fingers and hope for favourable conditions on the morning of our annual Lyrebird Survey which this year was held on Saturday May 30th. This year there was no rain but unfortunately the wind was up and noisy gusts were swirling through the canopy.
The logistics of getting a large crew of volunteers up and ready to participate at 6.15am means that we can’t afford to be flexible with our dates so it is a matter of carry on regardless. This year we had 22 volunteers turn up for the count, with most people pairing up, we were able to cover 12 out of our 16 monitoring stations, as is often the case the 4 stations in the southern section of our count area were left out.
Volunteers did a great job of arriving by 6.15 and by the time instructions were given and stations allocated it…
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In a radio interview this morning, Prime Minister Tony Abbott raised what he described as the “potential health impacts” of wind farms.
Yesterday’s article in The Australian by Liberal Democrat senator David Leyonjhelm highlighted some very good points about wind turbine noise and its effect on people living near them. People are complaining of a range of health related problems and are attributing them to wind turbines. The question is: what is the cause of these health problems?
Many blame the production of infrasound from wind turbines, yet this has not been proven to date. What is needed is new, comprehensive research to determine the true cause.
These concerns are currently being aired through a Senate Committee on wind farms and regulations, chaired by independent senator John Madigan.
Earlier this year the National Health and Medical Research Council found that there was no evidence that wind turbines directly affect health, but called for further research, particularly on the effects within 1.5 km of turbines.
I have been interested in how wind turbines produce noise, through a variety of research projects spanning several years. The most recent was an ARC Discovery project focusing on the fundamental noise-producing physics of wind turbine blades and the development of techniques to link personal annoyance with noise levels inside homes. My group and I have also investigated ways to reduce wind turbine noise by changing the shape of the blades and to steal ideas from owls, who have the ability to fly and hunt silently.
So are Leyonjhelm’s claims correct? Let’s run through them.
Claim: “Wind turbines emit infrasound and low-frequency noise.”
Wind turbines undoubtedly create infrasound. It is created by the movement of the blades through the air, as the blades pass the tower and, depending on the construction of the turbine, by the gearbox.
Claim: “Inappropriate levels of infrasound, regardless of the source, cause adverse health impacts.”
However, most experts believe that the level of infrasound produced by wind turbines is too low to be heard or create health problems. Recent measurements show that infrasound can propagate many kilometres from a wind farm – what we don’t know is if these very low level sounds can cause health effects.
Previous studies on the effects of infrasound on health have focused on the exposure of high levels of infrasound from industrial sources. These studies show that perception or physiological effects occur at levels that are many times those generated by wind farms.
Claim: “Research by NASA … established wind turbines could generate surprisingly high levels of infrasound and low frequency noise.”
While it is true that early designs of wind turbines created large amounts of low-frequency noise that was annoying (the so-called “downwind” turbines of the 1980s which were reported on by NASA), modern designs that place the rotors upwind of the tower have greatly reduced this problem and made wind turbines quiet enough for widespread use.
There have also been many years of intensive research and development into the design of quiet wind turbine rotors and operational methods to reduce noise. This is not to say that wind farm noise is not responsible for reported health problems.
The effect of sensitization after long exposure to low-level noise, the effects on sleep and the role of moderating factors must be considered along with noise generation and propagation effects to properly understand why so many people are complaining of health problems near wind farms.
Claim: “Wind farms are not required to limit or even monitor their infrasound emissions.”
There are no requirements for infrasound to be monitored near wind farms because it occurs at a very low level and is not expected to be heard by most people. It is also very difficult to measure, especially in the presence of wind that will also generate infrasound of the same or higher level when it passes through trees or blows over a house.
Even when we do record it, we don’t yet know what level is responsible for causing health problems.
What is needed is new multi-disciplinary research linking engineers with medical and health scientists where noise data and health information are recorded simultaneously for people living close to and far from wind farms. Only such detailed research can help provide an answer to this challenging and perplexing problem.
It’s now five years since the International Year of Biodiversity, and nearly 15% of Earth’s land surface is protected in parks and reserves. By 2020, we should reach the agreed global target of 17%. This is good news for species diversity, right?
Not really. Biodiversity loss continues apace despite these global agreements and conservation actions, and is unlikely to stop any time soon.
We explored this apparent paradox with the help of a simple model that simulates the current relative proportions globally of the area of remaining tropical forest, and the area that has been cleared for agricultural development. We used the model to look at what happens to these proportions when networks of conservation reserves expand.
Our research led to two insights: both the area of forest protection and the area of clearing for development can expand at the same time; and the governance regimes responsible for protected areas can actually be weakened by protected area expansion. This is because pressure for the creation of new protected areas comes largely from public discourse.
Forests and forces
In our model we depicted tropical forestlands as consisting of protected forests; traditionally managed or “unallocated” forests; and cleared agricultural land – plausible categories that broadly reflect the current status and areas.
We then modelled the different governance regimes (and feedbacks such as public discourse) responsible for this current status, regimes that:
a) protect unallocated forest;
b) develop (and clear) unallocated forest for agriculture;
c) maintain current habitat and restore agricultural land to forest, thereby opposing clearing for development.
We use the model to present three plausible scenarios of governance regime and land-use change trajectories.
Our dynamic hypothesis depicted in the figure shows how the driving forces of development and protection, while competing for the remaining stock of forest habitat, do not necessarily oppose each other. Consequently the total stock of forest habitat can decrease while the area of protected forest increases.
The force that directly opposes clearance of forests for development is the one that maintains existing unprotected forest use regimes or that seeks to restore cleared forest.
The relative power of the governance regimes that “develop”, “protect”, or “maintain/restore” will determine what ultimately happens to the area of remaining forest habitat. Biodiversity loss will only stop when the net loss of forest habitat each year is zero – which means halting the clearing of tropical forest for agricultural development, as well as increasing protected areas.
But in the real world we are doing the opposite – investing heavily in the force that drives tropical forest clearing. The leaders of the G20 nations recently gave a huge boost to the power of development regimes, by pledging to invest up to US$70 trillion on new infrastructure projects by the year 2030. This is precisely the kind of driving force that will harm wildlife conservation, and which the growth of protected areas will fail to counter.
It seems counter-intuitive, but our research suggests that increasing the area of the world’s conservation reserves can also reduce the perception of the risk of ongoing biodiversity loss, primarily because the focus on the 17% protection targets takes our eye off the critical issue of halting habitat loss. As a result, the global distribution of protected areas is currently “high and far”, skewed toward mountainous areas and places far from development frontiers. If achieving 17% leads the public to conclude that biodiversity is now safe, it can lower the main feedback currently giving power to the protect force – public pressure for political action.
This is compounded by the phenomenon of extinction debt – the time delay between habitat loss and the resulting extinction of species that live here – which hides the impact of development on wildlife in both protected and unprotected areas.
What do we do about it?
Conservation has traditionally sought to identify and protect “representative samples” of different types of ecosystems. Recently, however, there has been an increased interest in identifying and protecting areas based on cost-effectiveness criteria.
We suggest instead that one useful leverage point for slowing tropical biodiversity decline would be to concentrate on placing protected areas near active agricultural frontiers, which could help to constrain the march of agriculture through tropical forests.
This approach has already been shown to work in urban planning, including in Australia, where it has been used to fight urban sprawl. A second useful leverage point is to set global targets that include both a percentage for protection and an overall percentage for remaining forest habitat. Globally, forest cover now is at 62% of its original extent, while 75% has recently been identified as the extent necessary to stay within planetary boundaries.
Sharing is caring
There is currently much debate in the conservation literature about “land sparing or land sharing”. Our scenarios suggests that while land sparing through rapid protected area expansion has immediate conservation benefits, these benefits are lost over time as species populations eventually crash. The land-sharing scenario, through strengthening the power to maintain current forest habitats, suggests better biodiversity outcomes in the long term.
Realising these long-term benefits may only be possible with a resurgence in traditional forest-management practices that promote wildlife-friendly agriculture, and that restore forest habitat. All too often the governance regimes of traditional forest owners have been subsumed by the State in order to allow commercial forestry or forest clearance for agriculture. However, there are signs that this may be changing in some places through commercially viable drivers of sustainability.
Our analysis suggests that human activity will continue to damage wildlife diversity, in spite of successful efforts to meet the target of protecting 17% of Earth’s land surface. The reason is that a large percentage of natural habitats are disappearing in the face of development, particularly through the clearing of tropical forests for agriculture.
This destruction will continue because the overall balance of land management is still geared towards ongoing clearing for development rather than sustainable re-development of our current human footprint. Getting out of this trap will require an understanding of the processes that reinforce this perverse situation, and the realisation that this system needs to be redesigned.
This is a new frontier in conservation science, and our new analysis is hopefully a first step towards unravelling this complex social-ecological problem.
What we need to do next is to identify the critical feedback relationships that can empower natural resource management, and to put reasonable limits on the power of development regimes. Otherwise, the world’s biodiversity will continue to dwindle even if conservation reserves expand rapidly.
This article was coauthored by Craig Miller, a former researcher with CSIRO Sustainable Ecosystems.
Ro Hill is Principal Research Scientist, Ecosystems, Biodiversity Knowledge and Services Program at CSIRO.
Barry Newell is Visiting Fellow, Fenner School of Environment and Society at Australian National University.
Iain Gordon is Chief Executive at James Hutton Institute.
Michael Dunlop is Senior Research Scientist: land-water-biodiversity-climate at CSIRO.