“Make a list of all the environmental and social problems that today afflict us and our poor battered planet. – not just the extinction of species and animals and plants, that fifty years ago was the first signs of impending global disaster, but traffic congestion, oil prices, pressure on the health service, the growth of mega-cities, migration patterns, immigration policies, unemployment, the loss of arable land, desertification, famine, increasingly violent weather, the acidification of the oceans, the collapse of fish stocks, rising sea temperatures, the loss of rain forest. The list goes on and on. But they all share an underlying cause. Every one of these global problems, environmental as well as social becomes more difficult – and ultimately impossible - to solve with ever more people.”

Source: 1960s - 1980s, MANAGEMENT: Tasks, Responsibilities, Practices (1973), Part 1, p. 317

A steady-state economy, 2008

Rainforests and the Timeless Metaphors of Dreams by Manav Gupta (August 1997)
"on my eyot, umbilical cords of earth" by Manav Gupta (May 1999)
One minute films on environment consciousness (Commissioned by the Govt. of India) (2005)
1990s

Source: The Geological Evidences of the Antiquity of Man (1863), Ch.20, p. 393
Context: I endeavoured to sketch out (and it was, I believe, the first systematic attempt to accomplish such a task) the laws which govern the extinction of species, with a view of showing that the slow, but ceaseless variations, now in progress in physical geography, together with the migration of plants and animals into new regions, must, in the course of ages, give rise to the occasional loss of some of them, and eventually cause an entire fauna and flora to die out; also, that we must infer, from geological data, that the places thus left vacant from time to time, are filled up without delay by new forms, adapted to new conditions, sometimes by immigration from adjoining provinces, sometimes by new creations. Among the many causes of extinction enumerated by me, were the power of hostile species, diminution of food, mutations in climate, the conversion of land into sea, and of sea into land, &c.

Source: Democracy and freedom. 1919, p. 43; Cited in: John Cunningham Wood, Michael C. Wood (eds). George Elton Mayo: Critical Evaluations in Business and Management, Volume 1. 2004, p. 78

new viruses
"Implosion" https://web.archive.org/web/20121013194328/http://www.thatsmags.com/shanghai/article/414/implosion (2011)

Progress, Coexistence and Intellectual Freedom (1968), Dangers, The Threat to Intellectual Freedom

Twitter https://twitter.com/marwilliamson (22 Oct 2019)
Williamson's quotes in social media

Jared Polis, "Boulder, Colorado's Sesquicentennial", Congressional Record, June 25, 2009.