 crop diversity. Why it matters? 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 means? When 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 40,000 plant species on our planet and approximately half of them are edible. 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. Over the 20th century we have lost 75% of our crop diversity. The main reason for this is the dramatic decline in the fact that our industrialized food system focuses on high crop productivity, standardization and uniformity rather than diversity. 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 an offer. 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 left in 1983 and 408 pea varieties were reduced to just 25. Some of the lost species might still exist in somebody's garden or stored in a dusty seed jar in some basement but they disappeared from our seed catalogs and hence are not available for commercial farming anymore. A risk to food security. Decline in crop diversity poses a huge threat to food security and human health. With a global population expected to reach about 9.7 billion people in 2050 food security remains a major challenge. It may seem counter-intuitive 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. 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 1 million people and in the years to follow at least another million people fled the country. Especially with the prospect of climate change crop failures are expected to become more frequent. 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. Decline in crop diversity and human health. Food security however is not only about quantity but also quality. Estimates suggest that one in three people suffers from micronutrient deficiencies at the same time almost 2 billion people are overweight or obese. 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. However, reduced crop diversity makes it difficult to supplement the energy dense part of the human diet with nutrient rich foods. This in combination with globalization have caused human diets to become more uniform and less healthy all over the world. Reversing the downward trend. Luckily in recent years we've seen an increase in recognition of the importance of crop diversity. An important step in maintaining and increasing seed diversity is the creation of so-called gene banks. Today more than 1,750 gene banks all over the world collect, preserve and share all different kinds of seeds for agricultural research and the development of new varieties. 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. What can you do as a consumer? If you want to support crop diversity look out for rare varieties. Farmers markets often have a bigger selection you might find it easier to access rare varieties 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. Has listening to this article given you a new perspective on crop diversity? Let us know on the social media linked in the description box. This article was written by Lena Dilly and read by me Eloise Adler. Originally posted on foodonfolded.com. Food Unfolded explores the stories behind the food on our plate. Reconnecting us to the origins and sustainability of our food. Co-funded by the EU and powered by EIT food.