A recent article in the Independent is, in my opinion, a good example of how ideology can overwhelm evidence and logic. The article is basically an advertisement for a book, Dead Zone by ornithologist Philip Lymbery , which is out in paperback this week.

Lymbery’s thesis is that bird and other animal populations are steadily declining due to modern farming. If we want to stabilize the environment, and stop or reverse this trend, we need to make major changes to how we grow our food. He then advocates for organic farming and a return to older farming practices. He blames the situation on the attempt to maximize food production.

I think that Lymbery has correctly identified a real problem – an alarming decline in wild species over the last century. However, his proposed solution would actually make the problem worse. It is a classic example of narrative or ideology getting in the way of evidence-based solutions.

I don’t pretend to have any magic solution to the current issues Lymbery discusses. It is important to recognize that they are very complex, and we need to think carefully about what the real source of the problems are and what the best solutions might be.

Lymbery, as an ornithologist, has expertise when it comes to understanding bird populations and reasons contributing to their decline. However, he does not have farming expertise, and his statements about farming sound like knee-jerk appeal to nature fallacies, rather than informed opinion.

I think there are a number of premises that we can agree on, so let’s start there. Wild populations numbers are declining, including small mammals, the birds that feed on them, other bird species, and some insect species as well. The growth in human population, modern industry, and the need to feed over 7 billion people is also the primary cause. Basically – people are making this happen. No argument there.

I also think there is no argument about some of the causes – loss of habitat, fertilizers and pesticides getting into the environment, and climate change are among them.

Where we apparently disagree is on the relative contribution of these various causes, which directly relates to which solutions are likely to work. Lymbery claims that politicians are blaming everything on climate change. Well, maybe in the UK, in the US this issue is sharply divided along party lines. In any case, he seems to be making the opposite fallacy of dismissing climate change as an important contributor. We can agree that climate change is not the sole problem, and we do need to look closely at our farming practices.

The primary difference between Lymbery’s approach and reality, it seems to me, is on the relative contribution of habitat loss vs industrial farming practices. Lymbery’s proposes solution (shifting to organic farming) would decrease the use of some pesticides in farming, but would not eliminate them. It would actually just cause a shift to more toxic and less effective (but “natural” pesticides). This would be a disaster.

The even worse problem with organic farming is that it is less productive. This means we would produce fewer calories per acre, and we would therefore need more land to meet our good needs. Even with gains in farming practices that quality for the arbitrary label of “organic”, and even with reductions in food waste, we simply could not grow enough food organically to feed the world. Estimates are that organic farms overall (this varies greatly by crop) are about 20% less productive than conventional farming.

A switch to organic farming would therefore require more land used for farming. How much more? That is a complex question. Current estimates are that we are currently using 11% of all the land on earth for farming. How much land is suitable for farming has different answers depending on how you define “suitable”.

There is a continuum of suitability and no objective place to draw the line. We are essentially using all the land that is optimal for farming. As we expand our land use for additional farming, we will be expanding into less and less suitable land. This could be land that is sloped so that tractors cannot be used, or has limited access to water, or has poor soil conditions, etc. So essentially, the more we need to expand into less and less suitable land for farming, the less efficient our farming will be in terms of production per acre. So if we switch to farming practices that are 20% less efficient we will need more than 20% more land for farming, because we will be expanding into less and less suitable land.

This all gets back to – what are the major causes of wildlife loss due to human activity. This, of course, is also a complex question. However, in my reading over the years loss of habitat is always considered to be the major cause. At the very least it has to be considered a major cause.

It will take careful analysis to definitively answer this question, but it seems reasonable to assume for now, based on current evidence, that further reduction in habitat (by converting more land into farmland) would have a massive negative effect on wildlife. This negative effect is likely to overwhelm any benefits in changing farm practices – even if organic farming were an advantage, but it isn’t.

Further, when we explore options for reducing the impact of modern farming on the environment, we should have all tools and options at our disposal. Organic farming arbitrarily reduces these tools, by, for example, banning certain technologies, like genetic modification. GM crops that can grow with fewer inputs have the potential to massively reduce the footprint of modern farming. Banning this technology would have a definite negative effect.

Population control often comes up in these discussions. I agree that we need to think about our population growth, and we do need to stabilize the human population. The one zero-sum game in terms of resources is land. There is a finite amount on the Earth, and the more we use for us, the less is available for wildlife. There is no escaping this (until we literally escape the Earth).

There is often the unstated premise, however, in those advocating for radically changing our farming practices that they intend this to go along with a large reduction in the human population. They don’t often state this explicitly, but when you push them they acknowledge that, yes, this only works if we reduce the population. They will get their way if a shift away from modern farming results in massive starvation.

Meanwhile there are also lots of things we can do to farm more intelligently, without increasing our land use, reducing our productivity, or causing starvation. For example, setting aside wildlife refuges (such as patches of land where local plants are allowed to grow and feed the local wildlife) could reduce the impact of farming.

In the end what we need are evidence-based solutions based on careful research. We don’t need ideology, the appeal to nature fallacy, or marketing narratives.