TY - JOUR
T1 - The Doomsday Equation and 50 years beyond
T2 - new perspectives on the human-water system
AU - Parolari, Anthony J.
AU - Katul, Gabriel G.
AU - Porporato, Amilcare
N1 - Funding Information:
The authors acknowledge support from the US National Science Foundation (AGS-1102227, CBET-1033467, EAR-1344703, EAR-1331846, EAR-1316258, and FESD-1338694), the US Department of Agriculture through the Agriculture and Food Research Initiative (2011-67003-30222), and the US Department of Energy through the Office of Biological and Environmental Research Terrestrial Carbon Processes program (DE-SC0006967 and DE-SC0011461).
Publisher Copyright:
© 2015 Wiley Interdisciplinary Reviews: Water.
PY - 2015/7/1
Y1 - 2015/7/1
N2 - In 1960, von Foerster et al. humorously predicted an abrupt transition in human population growth to occur in the mid-21st century. Their so-called ‘Dooms-day’ emerged from either progressive degradation of a finite resource or faster-than-exponential growth of an increasingly resource-use efficient popula-tion, though what constitutes this resource was not made explicit. At present, few dispute the claim that water is the most fundamental resource to sustainable human population growth. Multiple lines of evidence demonstrate that the global water system exhibits nontrivial dynamics linked to similar patterns in population growth. Projections of the global water system range from a finite carrying capacity regulated by accessible freshwater, or ‘peak renewable water,’ to punctuated evolution with new supplies and improved efficiency gained from technological and social innovation. These projections can be captured, to first order, by a single delay differential equation with human–water interactions parameterized as a delay kernel that links present water supply to the population history and its impacts on water resources. This kernel is a macroscopic representation of social, environ-mental, and technological factors operating in the human-water system; however, the mathematical form remains unconstrained by available data. A related model of log-periodic, power-law growth confirms that global water use evolves through repeated periods of rapid growth and stagnation, a pattern remarkably consistent with historical anecdotes. Together, these models suggest a possible regime shift leading to a new phase of water innovation in the mid-21st century that arises from delayed feedback between population growth and development of water resource.
AB - In 1960, von Foerster et al. humorously predicted an abrupt transition in human population growth to occur in the mid-21st century. Their so-called ‘Dooms-day’ emerged from either progressive degradation of a finite resource or faster-than-exponential growth of an increasingly resource-use efficient popula-tion, though what constitutes this resource was not made explicit. At present, few dispute the claim that water is the most fundamental resource to sustainable human population growth. Multiple lines of evidence demonstrate that the global water system exhibits nontrivial dynamics linked to similar patterns in population growth. Projections of the global water system range from a finite carrying capacity regulated by accessible freshwater, or ‘peak renewable water,’ to punctuated evolution with new supplies and improved efficiency gained from technological and social innovation. These projections can be captured, to first order, by a single delay differential equation with human–water interactions parameterized as a delay kernel that links present water supply to the population history and its impacts on water resources. This kernel is a macroscopic representation of social, environ-mental, and technological factors operating in the human-water system; however, the mathematical form remains unconstrained by available data. A related model of log-periodic, power-law growth confirms that global water use evolves through repeated periods of rapid growth and stagnation, a pattern remarkably consistent with historical anecdotes. Together, these models suggest a possible regime shift leading to a new phase of water innovation in the mid-21st century that arises from delayed feedback between population growth and development of water resource.
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U2 - 10.1002/WAT2.1080
DO - 10.1002/WAT2.1080
M3 - Article
AN - SCOPUS:84971277861
SN - 2049-1948
VL - 2
SP - 407
EP - 414
JO - Wiley Interdisciplinary Reviews: Water
JF - Wiley Interdisciplinary Reviews: Water
IS - 4
ER -