Organic food is becoming increasingly popular. The Market Analysis page of the Organic Trade Association describes how organic food sales were $39.1 billion in 2014, nearly 5% of total food sales in the U.S., and up 11.3% from the previous year. It seems that nearly every grocery store now carries organic foods. I can't even find non-organic fresh herbs in my local grocery store.
There are a lot of hyped up claims about the health benefits of organic foods without a whole lot of data to back up those claims. There's also a lot of misunderstanding about what it actually takes to get classified as 'organic' from the USDA. For example, many organic farmers till use pesticides - they're just naturally occurring chemicals as opposed to synthetic ones. You can read about a lot of these issues in a Scientific American article, Mythbusting 101: Organic Farming > Conventional Agriculture.
But most of that is just hype, and if people are willing to pay extra money for a product that doesn't live up to all its claims, I believe P.T. Barnum may have had something to say about that*. My major problem with organic foods is where they actively cause harm to the environment. A good discussion on organic and conventional crop yields can be found in the entry on the Jayson Lusk blog, Organic vs Conventional Crop Yields. As Lusk points out, most large scale literature reviews find that organic crops on average give yields around 20-25% lower than conventional techniques (there's a lot of variability in that discrepancy depending on the particular crop). And as Lusk further went on to point out, conventional farming will always have an upper hand on organic, because even if some organic techniques are found to be beneficial, conventional farming can always adopt those particular techniques while still having other options that aren't available to organic**.
So, 20-25% lower yieds means that roughly 20-25% more cropland is required. Or to put that a different way, it means 20-25% more habitat destruction. And that's a big deal. Here's an excerpt from the World Wildlife Fund page on Impact of habitat loss on species.
Habitat loss is probably the greatest threat to the variety of life on this planet today.
It is identified as a main threat to 85% of all species described in the IUCN's Red List (those species officially classified as "Threatened" and "Endangered").
Increasing food production is a major agent for the conversion of natural habitat into agricultural land.
I know global warming gets most of the attention now as far as environmental disasters, but habitat loss is arguably worse. There are 7 billion people on this planet right now, and that's likely to increase to around 10 billion in the future, if not more. All those people need food, and most of that food has to be grown on farms. We should be doing everything we can to make those farms as productive as possible, minimizing habitat destruction as much as possible. We shouldn't be pushing for farming techniques that make that production 25% worse.
Most people buy organic foods because they want to eat healthy or because they are concerned about the environment and think organics reduce environmental problems. But they've been misled. The health claims aren't backed up, and the environmental impact is far more negative than most people realize.
*Actually, I still do have a problem with it, the same way I do with all false advertising. Organic proponents are pushing claims that aren't backed up by evidence, which is pretty misleading, though they probably believe the claims themselves so it's not exactly dishonest. And the saying about a sucker born every minute wasn't actually made by PT Barnum, but I'm sure he still had something to say about making money off of suckers.
**It reminds me of the passage from Tim Minchin's poem, Storm, "You know what they call alternative medicine / That's been proved to work? / Medicine."