“…the most important environmental liability of oil as an energy source is probably not air pollution or oil spills but the chance that war will be waged over access to the world's remaining supplies. The most important environmental liability of coal is not the occupational toll of mining or the public toll from coal-transport accidents …or the direct damage to public health from airborne sulfates… rather it is the threat of global climate change posed by accumulating atmospheric carbon dioxide, the consequences of which …are potentially enormous but highly resistant to convincing quantification. The most important environmental liability of nuclear fission is neither the routine nor accidental emissions of radioactivity, but the deliberate misuse of nuclear facilities and materials for acts of terrorism and war.”

[P.H. Gleick and J.P. Holdren. 1981. “Assessing Environmental Risks of Energy.” American Journal of Public Health, Vol. 71, No. 9, pp. 1046-1050 (September 1981).]

“Of all the pressing large-scale environmental problems facing society, global climatic changes appear to have the greatest potential for provoking disputes, worsening tensions, and altering international relations between developed and developing countries.”
[P.H. Gleick, 1989. "Greenhouse warming and international politics: Problems facing developing countries." Ambio. Vol. 18, No. 6, pp. 333-339.]

“Among all the major environmental threats, global climatic change appears to be the most likely to affect international politics because of its wide scope and magnitude.”
[P.H. Gleick, 1989. "Greenhouse warming and international politics: Problems facing developing countries." Ambio. Vol. 18, No. 6, pp. 333-339.]

“The supply and use of both water and energy resources are intricately connected, and we can no longer consider the formulation of rational energy policy and water policy to be independent.”
[P.H. Gleick, 1994. “Water and Energy.” Annual Reviews of Energy and Environment. Vol. 19:267-99.]

“Absent from traditional water planning has been any voice for natural ecosystems, any thought that the goals, aspirations, and desires of future generations may not be the same as those of the present generation, and any explicit representation of the complex interactions between land-surface processes, atmospheric behavior, the natural biota, and society. It is time for a change. A first step toward sustainable water use would be to guarantee all humans the water needed to satisfy their basic needs.”
[P.H. Gleick, 1996. "Basic water requirements for human activities: Meeting basic needs." Water International. Vol. 21, No. 2, pp. 83-92.]

“I recommend that international organizations, national and local governments, and water providers adopt a basic water requirement standard for human needs of 50 liters per person per day (l/p/d) and guarantee access to it independently of an individual’s economic, social, or political status. Unless this basic need is met, large-scale human misery and suffering will continue and grow in the future, contributing to the risk of social and military conflict.”
[P.H. Gleick, 1996. "Basic water requirements for human activities: Meeting basic needs." Water International. Vol. 21, No. 2, pp. 83-92.]

“The right to water sufficient to meet basic needs should be an obligation of governments, water management institutions, or local communities… Specifically, 50 liters per person per day of clean water should now be considered a fundamental human right.”
[P.H. Gleick, 1996. "Basic water requirements for human activities: Meeting basic needs." Water International. Vol. 21, No. 2, pp. 83-92.]

“A basic water requirement is a fundamental human right implicitly and explicitly supported by international law, declarations, and State practice. Governments, international aid agencies, non-governmental organizations, and local communities should work to provide all humans with a basic water requirement and to guarantee that water as a human right. By acknowledging a human right to water and expressing the willingness to meet this right for those currently deprived of it, the water community would have a useful tool for addressing one of the most fundamental failures of 20th century development.”
[P.H. Gleick, 1999. “The human right to water.” Water Policy, Vol. 1, No. 5, pp. 487-503.]

“All human beings have an inherent right to have access to water in quantities and of a quality necessary to meet their basic needs. This right shall be protected by law.”
[P.H. Gleick, P.H. 1999. “The human right to water.” Water Policy, Vol. 1, No. 5, pp. 487-503.]

“The imperatives to meet basic human water needs are more than just moral, they are rooted in justice and law and the responsibilities of governments. It is time for the international community to reexamine its fundamental development goals. A first step toward meeting a human right to water would be for governments, water providers, and international organizations to guarantee all humans the most fundamental of basic water needs and to work out the necessary institutional, economic, and
management strategies necessary for meeting them.”
[P.H. Gleick, 1999. “The human right to water.” Water Policy, Vol. 1, No. 5, pp. 487-503.]

“Among all the major environmental threats, global climatic change appears to be the most likely to affect international politics because of its wide scope and magnitude.”
[P.H. Gleick, 1989. "Greenhouse warming and international politics: Problems facing developing countries." Ambio. Vol. 18, No. 6, pp. 333-339.]

“An ethic of sustainability will require fundamental changes in how we think about water, and such changes come about slowly. Rather than endlessly trying to find the water to meet some projection of future desires, it is time to plan for meeting present and future human needs with the water that is available, to determine what desires can be satisfied within the limits of our resources, and to ensure that we preserve the natural ecological cycles that are so integral to human well-being.”
[P.H. Gleick. 2000. “The Changing Water Paradigm: A Look at Twenty-first Century Water Resources Development.” Water International, Volume 25, Number 1, March 2000, pp. 127-138.]

“Among all the major environmental threats, global climatic change appears to be the most likely to affect international politics because of its wide scope and magnitude.”
[P.H. Gleick, 1989. "Greenhouse warming and international politics: Problems facing developing countries." Ambio. Vol. 18, No. 6, pp. 333-339.]

"A communications and computer revolution is sweeping the globe. There is renewed interest in reaching out to outer space. International financial markets and industries are increasingly integrated and connected. And efforts are being made to ensure regional and global security. In this context, our inability to meet the most basic water requirements of billions of people has resulted in enormous human suffering and tragedy and may be remembered as our century’s greatest failure.”
[P.H. Gleick. 2000. “The Changing Water Paradigm: A Look at Twenty-first Century Water Resources Development.” Water International, Volume 25, Number 1, March 2000, pp. 127-138.]

“History shows that although access to clean drinking water and sanitation services cannot guarantee the survival of a civilization, civilizations most certainly cannot prosper without them.”
[P.H. Gleick, 2001. “Making Every Drop Count.” Scientific American, February, pp. 28-33.]

“The fastest and cheapest solution is to expand the productive and efficient use of water.”
[P.H. Gleick, 2001. “Making Every Drop Count.” Scientific American, February, pp. 28-33.]

“Addressing the world’s basic water problems requires fundamental changes in how we think about water, and such changes are coming about slowly. Rather than trying endlessly to find enough water to meet hazy projections of future desires, it is time to find a way to meet our present and future needs with the water that is already available, while preserving the ecological cycles that are so integral to human well-being.”
[P.H. Gleick, 2001. “Making Every Drop Count.” Scientific American, February, pp. 28-33.]

“Two paths lie before us: a ‘hard path’ that will rely almost exclusively on centralized infrastructure to capture, treat and deliver water supplies; and a ‘soft path’ that will complement the former by investing in decentralized facilities, efficient
technologies and policies, and human capital. This soft path will seek to improve overall productivity rather than to find new sources of supply. It will deliver water services that are matched to the needs of end users, on both local and community scales… The soft path will not be easy to follow. It will require institutional changes, new management tools and skills, and a greater reliance on actions by many individual water users rather than a few engineers. Yet when compared with the growing cost to society of continuing down the hard path, it is evident that a new way of thinking about our scarce water resources is long overdue.”
[P.H. Gleick, 2002. “Soft water paths.” Nature, Vol. 418, pp. 373. 25 July 2002.]

“Addressing the world’s basic water problems requires fundamental changes in how we think about water, and such changes are coming about slowly. Rather than trying endlessly to find enough water to meet hazy projections of future desires, it is time to find a way to meet our present and future needs with the water that is already available, while preserving the ecological cycles that are so integral to human well-being.”
[P.H. Gleick, 2001. “Making Every Drop Count.” Scientific American, February, pp. 28-33.]

“The soft path seeks to improve the overall productivity of water use and deliver water services matched to the needs of end users, rather than seeking sources of new supply.”
[P.H. Gleick, 2002. “Soft water paths.” Nature, Vol. 418, pp. 373. 25 July 2002.]

“Ultimately, meeting basic human and ecological needs for water, improving water quality, eliminating overdraft of groundwater, and reducing the risks of political conflict over shared water require fundamental changes in water management and use. More money and effort should be devoted to providing safe water and sanitation services to those without them, using technologies and policies appropriate to the scale of the problem. Economic tools should be used to encourage efficient use of water and reallocation of water among different users. Ecological water needs should be quantified and guaranteed by local or national laws. And long-term water planning must include all stakeholders, not just those traditionally trained in engineering and hydrologic sciences. The transition to a comprehensive “soft path” is already under way, but we must move more quickly to address serious unresolved water problems. We cannot follow both paths.”
[P.H. Gleick. 2003. “Global Freshwater Resources: Soft-Path Solutions for the 21st Century.” November 28, 2003, Science, Vol. 302, pp. 1524-1528.]

“The soft path for water strives to improve the productivity of water use rather than seek endless sources of new supply. It delivers water services and qualities matched to users’ needs, rather than just delivering quantities of water. It applies economic tools such as markets and pricing, but with the goal of encouraging efficient use, equitable distribution of the resource, and sustainable system operation over time. And it includes local communities in decisions about water management, allocation, and use.”
[P.H. Gleick. 2003. “Global Freshwater Resources: Soft-Path Solutions for the 21st Century.” November 28, 2003, Science, Vol. 302, pp. 1524-1528.]

“Treated wastewater isn't a liability, it’s an asset. We don’t need potable water to flush our toilets or water our lawns. One might say that’s a ridiculous use of potable water. In fact, I might say that. But that’s the way we've set it up. And that’s going to change, that’s got to change, in this century.”

[In Jon Gertner, “The Future is Drying Up.” The New York Times, October 21, 2007.]

“Thirty to 40 percent of all agricultural production comes from peak non-renewable water. We’re good at measuring the economic value, bad at measuring ecological value of water.”
[http://www.triplepundit.com/2013/10/20-inspiring-quotes-sxsweco-2013/. From the 2013 SxSWEco Conference, Austin TX)

“We're on a runaway train, scientists are blowing the whistle, but politicians are still shovelling coal into the engine.”

(The Independent, UK. http://www.independent.co.uk/environment/climate-change/arctic-could-become-ice-free-for-first-time-in-more-than-100000-years-claims-leading-scientist-a7065781.html )