It takes a lot of food to feed a global population of 8 billion people - and much of it depends on modern agriculture techniques, including the use of fertilizer.
Today phosphorus, potassium, and nitrogen (often referred to collectively as NPK) are widely recognized as macronutrients, substances required by plants in large quantities for optimal growth, but even before these chemical elements were discovered, farmers applied them to their fields in the form of manure and other minerals.
The Industrial Revolution paved the way for the development of synthetic fertilizers, and by the early 20th century, new technologies emerged that now help feed half of the world's population.
But for all the benefits they bring, fertilizers also have a significant impact on our planet. The modern-day synthetic nitrogen fertilizer sector is responsible for 1.31 gigatons (Gt) of CO2e each year, which is more than the aviation and shipping sectors combined.
What makes this sector unique is that only one-third of these emissions are associated with production; 84 percent of those fertilizer emissions come from ammonia synthesis, which typically requires natural gas as the feedstock.
Around two-thirds of fertilizer emissions are generated through their application in cropland, when CO2 and N2O are directly and indirectly emitted. It is important to note that these field emissions vary significantly around the globe and are also very difficult to accurately measure. But that does not mean mitigation is impossible; we can cut emissions from both production and application with technological advances, cleaner fuels, and better knowhow on the ground.
