How can nature-killing agriculture be more sustainable?

Modern agricultural systems have achieved astounding gains in productivity in the past 50 years, but they have come at an enormous cost to nature.

Farming is responsible for around a quarter of emissions warping the climate. It's also one of the primary drivers of biodiversity loss, responsible for threats to 80% of at-risk species, according to the United Nations.

Humanity relies on the diversity of plants and animals in the oceans, soils, sky and on land to make the planet habitable, by keeping the air and water clean, providing the basis for many medicines, and pollinating crops.

At the same time, humanity needs to produce enough food for 8 billion people. But there are ways to make the food system more nature- and climate-friendly.

"Every cropping system is going to require some simplification of nature and biodiversity. But there are some that are more biodiversity friendly than others," said Stephen Wood, an agricultural and food systems scientist with The Nature Conservancy and Yale University in the United States. 

Less land for farming, more for nature

Clearing of habitat is one of the main forms of farming-driven habitat loss. 

"That's happening worldwide at a pretty alarming rate," Wood told DW.

Crop and livestock farming is estimated to occupy some 50% of the world's habitable land. While ecosystems such as the Amazon, where cattle farmers are clearing rainforest, usually dominate the headlines, important native grasslands in countries like the US are also being plowed up for crops such as wheat.

Intensive livestock farming has the greatest impact on species loss, because of its high emissions, water pollution and the amount of food needed to feed the animals.

More wildlife-friendly and traditional methods, like herding cattle across long distances to summer and winter pastures, can bring biodiversity benefits. Grazing animals in these cases helps manage invasive pests and maintain grassland habitats important for ground-nesting birds, for instance, said Wood.

On the consumer-end, one of the best ways to reduce the harm caused by livestock farming is to eat less meat, according to environmental non-governmental organization WWF. Agricultural land use would decline 13% if people simply reduced their consumption of meat and dairy to the recommended dietary amount.

Monocultures: A biodiversity desert

Since the 1940s, giant monocultures have dominated farming, largely replacing small farms that grow multiple crops. The effects on biodiversity have been devastating, said pollination ecologist Barbara Gemmill-Herren.

"With large-scale monoculture, after a while it just becomes a sort of a desert for biodiversity," said Gemmill-Herren, who is a senior associate at the World Agroforestry Center, an international institute in Nairobi, Kenya. 

Bees and other pollinators — a key indicator of broader biodiversity — struggle to service such vast areas of monoculture. These single-crop farms lack other animal and plant species that combat the spread of diseases and pests. That in turn intensifies use of pesticide, herbicide and fertilizer, which can pollute rivers and streams, and damage the soil, as well as the insects and worms that birds feed on.

"Intensive farming of any sort, it's just inimical to the insects that really need to thrive, and along with insects comes everything else," said Gemmill-Herren.

While monocultures appear to be extraordinarily efficient at producing calories, this simple calculation hides their true cost, according to Gemmill-Herren.

The ecologist believes the global food system should take ecological and societal costs into account, alongside financial ones. That would result in more wildlife-friendly approaches to farming, like growing trees and shrubs among crops in fields, planting cover crops and mixed crops, said Gemmill-Herren.

But others question the effectiveness of this approach, saying that converting all farms to nature-friendly, pro-biodiversity operations might end up requiring far more land to produce enough food.

But what about herbicide, fertilizer and pesticide use?

Pesticides are a heavy fist that are overused and poorly targeted, according to Gemmill-Herren. The ecologist cited the emerging practice of agricultural companies coating seeds in pesticides, which is then distributed through pollen.

"The best practice in terms of pesticides is to only use them if you absolutely have to. To monitor and go out and really look at things and then decide if you need to use it or if you could use something else," Gemmill-Herren said.

In areas of Nepal such as the Chitwan Valley, Gemmill-Herren said chemical companies and educators have encouraged farmers to use pesticides well beyond what they need. This leads to a cycle of dependency.

Fertilizer overuse too is damaging biodiversity. Run-off into water systems leads to excess nutrient content that causes bursts of algae growth, which then block sunlight and suck oxygen out of the water as they decay, killing aquatic life.

A classic example of this in the US is the Mississippi Delta — where a dead zone bigger than Montenegro threatens one of the country's most important fisheries. Organizations such as The Nature Conservancy are working with farmers to use fertilizers more effectively, and to reconnect rivers to floodplains that filter out the nutrients.

Studies have also shown that over-dependence on herbicides such as glyphosate — which the European Union has just approved for use in the bloc for another year — are harmful to insects and aquatic life, affecting shellfish reproduction rates, for instance.

Weeds are also becoming increasingly resistant to glyphosate. Agencies such as the UN Environment Programme say farmers will be forced to switch back to more complex, but environmentally friendly weed control, such as plucking weeds mechanically or using selected crops and animals to manage the unwanted visitors.

Gemmill-Herren says she has seen heavy reliance on glyphosate in her home state of California. Farmers there use it three times a year — to banish weeds when crops are growing, to desiccate crops to make harvesting easier, and to clear fields of vegetation left over from the harvest.

Bayer, which produces the glyphosate-based herbicide Roundup, claims that its use actually improves biodiversity by requiring less land for farms, and enables no-till farming methods, which is better for overall soil health.

So what do we do?

Proponents of biodiversity should look at how farmers are supported or incentivized to manage their land in a way that protects nature, Wood said. That includes the private benefits of biodiversity they might reap, such as increased soil fertility, pollination and pest control. 

"For many biodiversity challenges it's pretty clear what the solutions are," Wood said. "If we want to restore ground nesting birds, we need to create habitats for ground nesting birds or if we want to create habitats for migrating sandhill cranes in in the US, we need to maintain flooded fields and make sure that there is adequate corn or rice grain left on the ground for them to use as a food source."

It's just a matter of building a system that encourages these practises, added Wood. 

The European Union, which has long faced criticism for the impact of its Common Agricultural Policy (CAP) on biodiversity, is increasingly trying to prioritize nature as part of the massive subsidy program. It's targeting smaller farms and providing funding for more nature-friendly approaches.

But environmentalists and scientists say recent changes to the CAP scheme still fail to adequately protect wildlife and continues to support damaging farming methods.

Edited by: Jennifer Collins