Intensive agriculture costs the environment less than previously thought

September 15th, 2018

New findings suggest that more intensive agriculture might be the “least bad” option for feeding the world while saving its species – provided that intensive agricultural systems prevents further conversion of wilderness to farmland.

There is mounting evidence that the best way to meet rising food demand while conserving biodiversity is to produce as much food as sustainably possible from the land we do farm, so that more natural ecosystems can be spared from conversion to farming land.

However, this involves intensive farming techniques thought to create high levels of pollution, water scarcity and soil erosion. Now, a study published today in the journal Nature Sustainability shows this is not necessarily the case.

Scientists have put together measures for some of the major “externalities” – such as greenhouse gas emission and water use – generated by high- and low-yield farming systems, and compared the environmental costs of producing a given amount of food in different ways.

The results from four major agricultural sectors suggest that, contrary to many people’s perceptions, more intensive agriculture that uses less land may also produce fewer pollutants, cause less soil loss and consume less water.

The study cautioned that if higher yields are simply used to increase profit or lower prices, they will only accelerate the extinction crisis we are already seeing.

“Agriculture is the most significant cause of biodiversity loss on the planet,” said study lead author Andrew Balmford, Professor of Conservation Science from the University of Cambridge. “Habitats are continuing to be cleared to make way for farmland, leaving ever less space for wildlife.”

“Our results suggest that high-yield farming could be harnessed to meet the growing demand for food without destroying more of the natural world. However, if we are to avert mass extinction it is vital that land-efficient agriculture is linked to more wilderness being spared the plough.”

Examples of high-yield strategies include enhanced pasture systems and livestock breeds in beef production, use of chemical fertilizer on crops, and keeping dairy cows indoors for longer.

The study analysed information from hundreds of investigations into four vast food sectors, accounting for large percentages of the global output for each product: Asian paddy rice (90%), European wheat (33%), Latin American beef (23%), and European dairy (53%).

The cross-disciplinary study involved scientists from 17 organisations from around the world, including colleagues from United Kingdom, Poland, Brazil, Mexico and Colombia.

Our contribution to the study was to provide and analyse data relating to livestock and their impacts on the “externalities” investigated, such as greenhouse gas emissions.

“We found that for Latin American beef systems, pasture systems that used more land also generated higher emissions” said co-author Dr Mario Herrero, Chief Research Scientist with CSIRO.

“This provides evidence that the intensive agricultural systems that we studied do not necessarily put greater pressure on the environment compared with less intensive systems. More research is needed to see whether for fruit or intensive horticulture the same holds true” added Mario Herrero.

The study authors say that high-yield farming must be combined with mechanisms that limit agricultural expansion if they are to have any environmental benefit. These could include strict land-use zoning and restructured rural subsidies.