We know about greenhouse gases and global warming, and how bad they are for us but we hardly know about the insidious killer in the form of the biologically active nitrogen. We cannot live without it but we also cannot live with it.
Biologically active nitrogen (also known as the reactive nitrogen) is essential in food production but too much of it in the environment is deadly. Unfortunately, we release huge quantities of it to the environment and we already suffer the consequences.
We fight political battles, engage ourselves in military combats, fight terrorism, but meanwhile unnoticed by most of us this insidious killer gradually but surely conquers the world. Its presence was negligible and harmless in 1860 but from the time we 'solved' the food production problem with the help of synthetic fertilisers, and from the time we 'solved' energy problems with the use of fossil fuels, nitrogen pollution increased rapidly and it continues to spread.
The maps below(for 1860, the early 1990s, and 2050), which are the courtesy of Jim Galloway (Galloway, et al. 2004) show the growing problem of nitrogen pollution. By 2050, the pollution will be so intense and so wide-spread that it will engulf nearly all parts of the world, but most of us will not even know what destroys us and the environment.
Global nitrogen depositions in 1860
Nitrogen depositions in that year were small and harmless.
Nitrogen depositions in the early 1990s
By the early 1990s, nitrogen depositions increased all over the world. They spread not only over the land but also over the seas. by that time, they created harmful pollution.
Projected nitrogen depositions in 2050
By 2050, the harmful biologically reactive nitrogen will conquer the world. It is not clear how we shall be able to cope with this enormous and deadly pollution.
Source: Galloway et al. 2004. (See also International Nitrogen Initiative.) Reproduced with kind permission of Jim Galloway.
Note: For a broader discussion of the nitrogen problem see Can We Feed the Word?
Galloway, J. N., Dentener, F. J., Capogne, D. G., Boyer, E. W., Howarth, R. W., Seitzinger, S. P., Asner, G. P., Cleveland, C., Green, P., Holland, E., Karl, D. M., Michaels, A. F., Porter, J. H., Townsend, A. R., and Vörösmarty, C. 2004, ‘Nitrogen Cycles: Past, present, and future’, Biochemistry 70:153-226.