Published: 17 December 2013

The real cost of pesticides in Australia's food boom

Nancy Schellhorn, Anna Renwick and Sarina Macfadyen

More than $17 billion worth of crops grown in Australia annually is attributed to agricultural pesticides. That’s a staggering 68 per cent of the $26 billion industry, according to a recent Deloitte report commissioned by CropLife Australia. So should we all pat ourselves on the back and eat up?

Insect predators such as this ladybird can control pests just as well as pesticides.

Credit: Nancy Schellhorn

Most of us want cheap, perfect-looking produce and farmers want to make a decent living. Agricultural pesticides have undoubtedly reduced food loss and helped farmers provide the unblemished produce we have grown so used to.

But pesticides also represent a significant source of risk for human and wildlife health, and pollution into our waterways. Should we be concerned about these ‘costs’, and how do we account for them?

What are the costs of pesticides?

Pesticides (insecticides, herbicides and fungicides) are applied over large areas in agriculture and urban settings. Their use represents an important source of diffuse chemical pollution that is difficult to monitor and difficult to control.

The overuse and reliance on pesticides has resulted in weeds and insects developing resistance to insecticides and herbicides. This results in excessive, ever-increasing pesticide use in an attempt to get on top of the problem.

For example, in the early 90s, the overuse of insecticides resulted in resistant cotton bollworm (a serious moth pest of cotton), which nearly brought the cotton industry to its knees. New technology – genetically modified cotton expressing a bacterial toxin that kills only moths including the bollworm – has been a saviour to the industry and insecticide use has reduced by 87 per cent.

Australia also has the worst weed-resistance problem in the world, and many herbicides are no longer an option for control. Producing crops at a profit may be at risk, and the only way to get on top of the problem is likely to be by non-chemical means.

Pests developing resistance to pesticides isn’t the only problem. The use of ‘broad-spectrum’ insecticides also wipes out all the good insects – the ones that eat the pests munching away at crops. Consequently, other pest insects that escaped the initial spray are able to grow large populations unchecked.

Unfortunately broad-spectrum pesticides are some of the cheapest chemicals in Australia costing only $1.50 per hectare to apply in grain crops, making them an obvious choice for many farmers. These issues in themselves are challenging to manage not to mention the cost to human health and wildlife.

Insects are animals with neurological systems, and many insecticides, particularly organophosphates – a widely used class of insecticides – are neurotoxins to insects and to humans. Organophosphates are still widely used in agriculture in Australia even though many have been banned in the EU, and banned or restricted in the USA. Rarely do we ever measure these costs.

What are the alternatives?

The challenge is to reduce the risk from excessive pesticide exposure while maintaining and increasing the level of crop productivity. What are our alternatives?

There is an extensive range of policy instruments used by many countries to address human and ecosystem health concerns and pesticide pollution of water and air. These include regulation; payments to encourage lower use and more accurate application; pesticide taxes to encourage greater use efficiency by farmers; and advice and information for farmers on ‘best practice’.

For example, in 2008 the French government launched EcoPhyto Plan with a goal to reduce the use of pesticides and plant protection products by 50 per cent by 2018, with an annual budget of ?41 million (A$61 million).

In 2009, the EU adopted ‘Integrated Pest Management’: legislation to achieve sustainable use of pesticides and prioritise non-chemical methods. The legislation takes effect in 2014.

This strategy will include a range of alternative management strategies to pesticides that can help control pests.

For pest insects, we can grow new crop varieties more tolerant to pest damage. We can manage weeds in fields and around field edges. We can conserve insect predators such as spiders and ladybirds. And we can selectively use insecticides that leave predators unharmed.

Research has also shown that native vegetation on farms can support these insect predators and native fauna. Managing vegetation to promote beneficial insects is known as ‘pest-suppressive landscapes’, which could be a part of integrated pest management.

Another method may be crop rotation that produces ‘biofumigation’ activity, such as mustards, which produce a compound that inhibits fungal growth. These strategies can reduce soil-borne pathogens and break the disease cycle.

Where next for Australia?

If we compare pesticide sales and crop production in Australia we find that both increased from the early 1990s to early 2000s.

But for many OECD countries we now find that crop production has been decoupled from growth in pesticides. Instead, crop production has been boosted by other factors, including education and training, payments for beneficial pest management, pesticide taxes, new pesticide products that can be used in smaller doses, and the expansion of organic farming.

In Australia there is actually very little data on pesticide use and environmental impact. This makes it difficult to judge how Australia is tracking against other countries, and how our flora and fauna are responding with continued exposure to these toxins.

Many groups and public lead alliances have expressed serious concerns about the way pesticides are regulated in Australia and about the implications for human health and the environment; several dozen pesticides banned in Europe are currently registered and used commonly in Australia.

Protecting crops against damage from weeds, insect pests and disease is an ongoing challenge. Integrated approaches, where chemical control is but one option – not the only option, and support for innovation from science, industry and farmers – will see us tackle these challenges.

Greater support for the development and registration of ‘softer chemicals’ that are less toxic to the farm workers, and the environment, is needed. Australian farming is one of our most trusted industries precisely because we take steps to protect our people and our environment. We can’t get complacent if we’re to maintain that trust.

Dr Nancy Schellhorn is Team Leader, Spatial Ecology at CSIRO. Dr Anna Renwick is a research ecologist at the University of Queensland. Dr Sarina Macfadyen is a research scientist at CSIRO. This article was originally published at The Conversation.

Published: 19 January 2015

Mapping East Asia’s disappearing tidal flats

Nick Murray

Who speaks for the tidal flat? There are many voices for the mangrove forest, the coral reef and the seagrass meadow, but the chorus for the mud, sand and silt flats that sit hidden under shallow water for most of the tidal cycle is often silent.

In China alone more than 1.2 million hectares of wetland reclamation has taken place in the last 50 years, perhaps accounting for more than 5 per cent of the worlds’ tidal wetlands.

Credit: Nick Murray

Not only do hundreds of species of migratory bird depend on them for their existence, this coastal ecosystem also protects large chunks of humanity and provides ecosystem services to hundreds of millions of people around the world.

A zone under pressure

The problem for all coastal ecosystems is the shifting character of the coastal zone. The last 50 years has seen the global human population migrating rapidly to coastal regions. As a result, coastlines around the world have become a focus of expansion of urban, agricultural and industrial areas.

This development is having a major impact on coastal ecosystems, which has resulted in the widespread loss and degradation of ecosystems such as mangroves, seagrasses, coral reefs and tidal flats. And that has major consequences for humans and nature.

In terms of the human cost, coastal ecosystems are a frontline defence that protects billions of dollars of infrastructure from storms and sea level rise, and maintaining their integrity is among the most cost-effective options for coastal protection.

Tidal flats are a widespread coastal ecosystem that is frequently overlooked in the planning and management of coastal resources. They are among the most widespread of any coastal ecosystem and, as well as providing ecosystem services to hundreds of millions of people worldwide, they sustain a suite of threatened and declining species.

For instance, tidal flats support the majority of the world’s migratory shorebird species, enabling their yearly migration from the arctic to areas as far south as Patagonia. Unfortunately, their proximity to centres of human population have also made these areas targets for cheap and rapid coastal development.

Drawing a mud map

So, what’s the magnitude of the problem?

Until now we have had no way of knowing just how much of this declining coastal ecosystem has been destroyed, or how much and where it remains. The principal reason for the lack of accurate maps of this ecosystem is due to the rapidly changing conditions they encounter: changing tides either expose or cover them, severely limiting the application of classical remote sensing methods.

To solve this problem, our small team of remote sensors and spatial ecologists have been developing methods to map tidal flats over very large areas.

Using the heavily developed tidal flats of mainland East Asia as a case study, we have developed a rapid mapping approach for identifying the distribution of tidal flats while assessing their changing status at continental scales.

The tidal flats in this region – which fringe the countries of North Korea, South Korea and China – are among the largest in the world, measuring up to 20 kilometres wide in some places. Our methods – utilising free data from the US Geological Survey’s Landsat archives and freely available regional tide models – allow fast implementation across thousands of kilometres.

Indeed, with more than 28,000 images to choose from, we determined the changing status of tidal flats across more than 14,000 kilometres of coastline.

Easily overlooked, and invisible for much of the tide cycle, mud flats are disappearing right before our very eyes. And their loss comes with an enormous cost.

Credit: Nick Murray

Impacts of reclamation

Our results demonstrate that tidal flats in East Asia are being destroyed at rates similar to other major at-risk ecosystems, such as tropical forests and mangroves. The principal cause of these losses related to coastal development. Changes to sedimentation regimes due to the damming of major rivers is also an issue as this results in offshore losses of tidal flats.

In East Asia, land scarcity is a severe issue and often the cheapest method of acquiring land for large coastal developments is through land creation, often termed reclamation. Tidal flats, which are generally characterised by low-sloping flats in areas protected from severe weather, have proven an ideal environment for cheap and rapid coastal development.

This radical transformation involves the construction of seawalls, infilling and finishing for land use. These areas are then developed into new parcels of land for aquaculture, agriculture, suburbs and industry.

Loss of coastal wetlands to land reclamation is a global problem that is severely affecting the world’s coastlines. In China alone more than 1.2 million hectares of wetland reclamation took place in the last 50 years, perhaps accounting for more than 5 per cent of the world’s tidal wetlands according to some estimates.

This is clearly a symptom of China’s rapid coastal urbanisation. This arc of growth will form one of the world’s largest urban areas by 2030 – a continuous coastal urban corridor over 1800 kilometres long.

The rapid pace of coastal population growth and sea-level rise – as well as increasing demand for aquaculture, coastal wind farms, and tide energy – will certainly apply further pressure to the world’s tidal flats in the future.

The loss of tidal flats along migratory pathways, especially staging sites (where birds must replenish their energy stores during migration for long, energetically expensive flights) can have extreme consequences for shorebird populations. For the millions of shorebirds that migrate through the East Asian-Australasian Flyway, the intertidal areas of Asia are a crucial migratory bottleneck.

Credit: Nick Murray

Uncertain future

An effective conservation strategy must manage the complex economic and social trade-offs that drive coastal development.

Decision-making that simultaneously plans for coastal development and coastal conservation along the world’s most rapidly developing shores is clearly needed.

For example, places where natural values have effectively been lost due to sediment depletion and coastal subsidence could be prioritised for development. As part of a carefully integrated plan, this could ease pressure on a functioning network of coastal protected areas and ensure continued delivery of ecosystem services.

Not only might this avert catastrophic extinctions of coastal biodiversity, it will also help us ensure we have a coastline capable of adapting to an increasingly uncertain future.

Dr Nick Murray is a Research Associate at the Centre for Ecosystem Science, University of New South Wales. He carried out this research in association with the Environmental Decisions Group (EDG), while completing his PhD at the University of Queensland. The EDG is a network of conservation researchers developing the science of effective decision making to better conserve biodiversity, and includes a number of Australian and International research centres, including CSIRO. This article first appeared in Decision Point – a free monthly online publication from the EDG.

More information

‘Tracking the rapid loss of tidal wetlands in the Yellow Sea’, published in Frontiers in Ecology and the Environment

‘Continental scale mapping of tidal flats across East Asia using the Landsat archive’, published in Remote Sensing

‘IUCN situation analysis on East and Southeast Asian intertidal habitats, with particular reference to the Yellow Sea (including the Bohai Sea)’, IUCN occasional paper

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