Almost half of the world’s current population is fed by nitrogen fertilizer produced by the Haber-Bosch process. So despite the often bad reputation of fertilizers in the popular press, almost twice the people are alive today than would be possible without industrial fertilizers. 

The problems related to the cascade of reactive nitrogen - once it manufactured, placed on the soil to produce crops, and lost via multiple pathways – are widely recognized.  These problems range from local to regional and global environmental issues such as, nitrate leaching into ground water, eutrophication of lakes and coastal zones, increasing greenhouse gas emissions from nitrous oxide.  These social costs of dealing with the excess nitrogen is often much higher than the benefits to individual farmers. 

Yet fertilizers play a key role in every day food security; this is partly because fertilizers and food prices have been relatively cheap the past several decades.     On a global level, the recent spikes in energy prices in 2008 and 2011, however, have made this connection between energy, fertilizers and food prices painfully clear.  Rising food prices have been met with riots and political unrest throughout the world. 

Less well recognized or appreciated is that household food insecurity and under nutrition in much of rural Africa is related to lack of fertilizers, with an average of 8 kg ha^-1 of nutrient applied per hectare compared to > 100 kg ha^-1 for most other regions. Though not a one-to-one correlation, human protein deficiency has been associated with these areas of low fertilizer N application.

Feeding a growing population with changing diets will require even more fertilizer.  Finding a balance between the costs and benefits will be a challenge as will be finding ways to reach rural Africa with affordable fertilizers to meet basic human needs.