EA - Everything I didn't know about fertilizers by Helene K

Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Everything I didn't know about fertilizers, published by Helene K on June 28, 2023 on The Effective Altruism Forum.At a recent EA meetup, someone mentioned fertilizers in the context of climate change and global food production. Admittedly, I had never thought about fertilizers before, except when I’ve been trying to get the tomato plants on my balcony to grow more than five tomatoes per season (I have yet to find my green thumb). Turns out fertilizers are a wildly fascinating topic! I dug into the topic a bit and decided to write up my findings as I assume others might also learn a lot about fertilizers and how they fit into the bigger picture.This post is the product of around twelve hours of research. It is by no means comprehensive and I wonder if I’ve come to the right conclusions in some sections. Any feedback is highly welcome, as well as corrections and resources that could fill in gaps or contradict anything I’ve written here.SummaryFertilizers provide what plants need to grow: nitrogen, potassium and phosphorus (in addition to sunlight and water).Humans have used organic fertilizers for thousands of years and started using synthetic fertilizers in the 20th century.While phosphate and potassium fertilizer is made from mined phosphorus and potash, respectively, nitrogen fertilizer is mostly produced through combining hydrogen from natural gas with atmospheric nitrogen via the Haber-Bosch process.58% of fertilizers are nitrogen fertilizers, with China, the US, India and Russia being the world’s largest producers. Potash is mainly mined in Canada, Belarus and Russia, phosphorus comes mostly from China.Fertilizers have vastly increased food production in the last 100 years and it is estimated that about 50% of today’s global population rely on fertilizers for their food supply, making fertilizers one of the “four pillars of civilization”.In comparison to almost all other regions in the world, crop yields in Sub-Saharan Africa are still very low, an unsettling fact given Sub-Saharan Africa’s fast population growth and high rates of undernourishment. This is partly the result of too little fertilizer use.Because fertilizer is so good at increasing crop yields, it means we can produce more food on the same or even less farmland, helping to preserve wildlife habitats and biodiversity.Many countries around the world use a lot of fertilizers—in fact, many use too much, including China, Mexico, Brazil, Colombia and Thailand, and could maintain their food production even with lower fertilizer use.Producing ammonia for nitrogen fertilizers relies heavily on natural gas, consumes around 2% of the global energy supply and constitutes about 5% of global anthropogenic greenhouse gas emissions, so we need to find ways to produce nitrogen fertilizer more sustainably.There is a range of ongoing development for producing “green ammonia” but most of them are still in their early stages, and it is unclear whether new production technologies can cover future needs for ammonia.Although higher crop yields and fertilizer use seem to be vital for improving food security in Sub-Saharan Africa, the issue is relatively unexplored in EA. It seems worthwhile to have a deeper look into this issue and think about potential cost-effective interventions as well as how they compare to top interventions in global health and development.What are fertilizers?Plants need three things to grow: sunlight, water and nutrients. Fertilizers provide plants with the latter, more specifically with phosphorus, potassium and nitrogen [1].Hang on, but why do we need to give a plant nitrogen? Isn’t our air made up of 78% nitrogen? Yes, but atmospheric nitrogen cannot be used by plants directly and instead needs to be converted into ammonia or other nitrogenous compounds in the soil. This process...