HomeArticlesHistory & Culture The FAO estimates that we lost 75% of our crop diversity during the 20th century. This trend is threatening food security and human health. But in recent years awareness has increased and efforts to reverse this trend are being made. Crop diversity: What it meansWhen we wander around the fruit and vegetable aisles in the supermarket, most of us are not aware of the fact that what we see is just a small fraction of what could be there. Scientists estimate that there are about 400,000 plant species on our planet and approximately half of them are edible.1,2 Throughout human history, we have probably used around 7,000 plant species in our agricultural systems. Yet, today only about 30 crop species make up 90% of the calories in our diet and only three species (rice, wheat, and maize) account for roughly half of the human calorie supply.3,4Over the 20th century, we have lost 75% of our crop diversity.5 The main reason for this dramatic decline is the fact that our industrialised food system focuses on high crop productivity, standardisation, and uniformity rather than diversity.4 In the current setting, a handful of multinational companies supply the majority of commercial seeds. These companies only invest in a limited variety of seeds and therefore, decide what is on offer.6 A US study found that out of 544 different kinds of cabbage in 1903 only 28 survived until 1983. Out of 307 maize varieties, only 12 were left in 1903 and 408 pea varieties were reduced to just 25. The list goes on.7, 8 Some of the lost species might still exist in somebody’s garden or are stored in a dusty seed jar in some basement. But they disappeared from our seed catalogues and hence are not available for commercial farming anymore.7 A risk to food securityDeclining crop diversity poses a huge threat to food security and human health.7, 9 With the global population expected to reach about 9.7 billion people in 2050,10 food security remains a major challenge. It may seem counterintuitive but focusing on highly productive crop varieties, while ignoring the qualities of less productive varieties, threatens overall food security. Relying on a small number of crop species and varieties makes the food system vulnerable to shocks such as droughts, pests, and diseases.6,11 In a uniform agricultural system, the failure of one key crop can have disastrous consequences. A good example is the famous Irish potato famine of the 19th century. When a large part of the Irish population relied on just one potato variety, a potato blight destroyed most of the harvest. The effects were devastating, causing the death of about one million people. And in the years to follow at least another million people fled the country.12Especially with the prospect of climate change, crop failures are expected to become more frequent.6 Crop diversity plays a key role in addressing this challenge. Diverse crop varieties have diverse qualities. Some are highly productive, while others are more resilient to droughts, pests and diseases and perform better in adverse conditions. Therefore, high crop diversity increases the resilience of our food system and thus food security.Declining crop diversity and human health Food security, however, is not only about quantity but also about quality. Estimates suggest that one in three people suffers from micronutrient deficiencies. At the same time almost 2 billion people are overweight or obese.13 So in order to fight malnutrition and diet-related diseases, people not only need access to calorie-rich foods but also access to diverse food and the full range of nutrients.11, 14 However, reduced crop diversity makes it difficult to supplement the energy-dense part of the human diet with nutrient-rich foods.6 This, in combination with globalisation have caused human diets to become more uniform and less healthy all over the world.6, 15Reversing the downward trendLuckily, in recent years we’ve seen an increasing recognition of the importance of crop diversity.4, 11 An important step in maintaining and increasing seed diversity is the creation of so-called gene banks. Today more than 1750 gene banks all over the world collect, preserve and share all different kind of seeds to promote agricultural research and the development of new varieties.16,17 However, the accessibility to (new) varieties remains a challenge and the full potential of gene banks for breeding and research still needs to be explored.17 What can you do as a consumer?If you want to support crop diversity, look out for rare varieties. Farmer's markets often have a bigger selection, you might find it easier to access rare for your own garden or balcony to grow your own food. By collecting the seeds you can even cultivate your own variety, which over the years will be adapted to your local conditions. Do you support crop diversity by growing your own food? Let us know in the comments.