@article {77,
	title = {Regime Shift in Fertilizer Commodities Indicates More Turbulence Ahead for Food Security},
	journal = {PLOS One},
	volume = {9},
	year = {2014},
	month = {May},
	abstract = {Recent human population increase has been enabled by a massive expansion of global agricultural production. A key component of this "Green Revolution{\textquoteright}{\textquoteright} has been application of inorganic fertilizers to produce and maintain high crop yields. However, the long-term sustainability of these practices is unclear given the eutrophying effects of fertilizer runoff as well as the reliance of fertilizer production on finite non-renewable resources such as mined phosphate-and potassium-bearing rocks. Indeed, recent volatility in food and agricultural commodity prices, especially phosphate fertilizer, has raised concerns about emerging constraints on fertilizer production with consequences for its affordability in the developing world. We examined 30 years of monthly prices of fertilizer commodities (phosphate rock, urea, and potassium) for comparison with three food commodities (maize, wheat, and rice) and three non-agricultural commodities (gold, nickel, and petroleum). Here we show that all commodity prices, except gold, had significant change points between 2007-2009, but the fertilizer commodities, and especially phosphate rock, showed multiple symptoms of nonlinear critical transitions. In contrast to fertilizers and to rice, maize and wheat prices did not show significant signs of nonlinear dynamics. From these results we infer a recent emergence of a scarcity price in global fertilizer markets, a result signaling a new high price regime for these essential agricultural inputs. Such a regime will challenge on-going efforts to establish global food security but may also prompt fertilizer use practices and nutrient recovery strategies that reduce eutrophication.},
	isbn = {1932-6203},
	doi = {10.1371/journal.pone.0093998},
	url = {http://dx.doi.org/10.1371/journal.pone.0093998},
	author = {Elser, J. J. and Elser, T. J. and Carpenter, S. R. and Brock, W. A.}
}
@article {68,
	title = {General Resilience to Cope with Extreme Events},
	journal = {Sustainability},
	volume = {4},
	year = {2012},
	pages = {3248-3259},
	abstract = {Resilience to specified kinds of disasters is an active area of research and practice. However, rare or unprecedented disturbances that are unusually intense or extensive require a more broad-spectrum type of resilience. General resilience is the capacity of social-ecological systems to adapt or transform in response to unfamiliar, unexpected and extreme shocks. Conditions that enable general resilience include diversity, modularity, openness, reserves, feedbacks, nestedness, monitoring, leadership, and trust. Processes for building general resilience are an emerging and crucially important area of research.},
	isbn = {2071-1050},
	doi = {10.3390/su4123248},
	url = {http://dx.doi.org/10.3390/su4123248},
	author = {Carpenter, S. R. and Arrow, K. J. and Barrett, S. and Biggs, R. and Brock, W. A. and Crepin, A. S. and Engstrom, G. and Folke, C. and Hughes, T. P. and Kautsky, N. and Li, C. Z. and McCarney, G. and Meng, K. and Maler, K. G. and Polasky, S. and Scheffer, M. and Shogren, J. and Sterner, T. and Vincent, J. R. and Walker, B. and Xepapadeas, A. and de Zeeuw, A.}
}
