“Over the coming decades, rises in global demand for food, fibre, feed and fuel are predicted to cause large increases in the amount of water used by agriculture.”

What do you think is driving these “large increases”?

David Tribe’s opening statement makes the clear connection between increased water-use efficiency and continuous population growth. Not only that, but this continuous increase in demand is his primary motivation for being involved in this honourable field.

And then one correspondent writes; “Ludwig, all this population stuff is completely irrelevant to the issue.”

Ugh!

hey realist, i think there is a possible trend towards high rise 'factory farms'. there is one planned for chicago i think.

http://www.verticalfarm.com/essay.htm

the real beefit is both the lower water use as well as the lower production/transportation costs because they are closer to the consumer. i think the one planned for chicago is becoming more viable with every rise in petrol prices, while the price of production is higher per tomato the transport costs is less.

Realist and its not easy being.

Can you tell me what you are going to replace sunlight with in your high rise hydroponic factories.
If your answer is artifical light then factor in the energy costs, greenhouse gases.

Until we invent clean, green, low cost energy I think you will relying on people like David Tribe and the farmers to put food on your tables for a long while yet.

“Over the coming decades...large increases in the amount of water used by agriculture.”
What do you think is driving these “large increases”?

Well Ludvig, it is too simplistic to nominate population growth as the driver, or economic growth for that matter. In China for example, poverty could well be called the driver, but paradoxically, elimination of poverty can trigger demographic transitions which allow populations to stabilise.

So no, David Tribe’s opening statement does not necessarily make a clear, necessary, connection between increased water-use efficiency and continuous population growth, and I'm not sure, Ludvig, you've fully captured my motivation for being involved in this honourable field.

I am very motivated about using technology and wealth to decrease water, land, carbon, nitrogen, and energy "footprints" on the planet. In my view industrial ecology, in the sense pioneered by Jessie Ausubel, is crucial to good planetary stewardship, and as Perseus shows, human imagination, new ideas and optimism help.

And to anticipate other worries about materialist overload of the planet, its really too simplistic also to identify economic growth in any simple way as the driver for excessive overload on resources. Economic development is full of surprises, famously encapsulated by Alan Greenspan's remark "The Weightless Economy". This refers to the fact that the weight of materials in the annual output of the US economy has not increased since 1900. Today the internet and wireless coms are putting copper wire telephones out of business.

David, I think you would be really battling not to call population growth the main driver of continuously increasing agricultural production. Yes, once you start to dig into the issues, it is more complex. In some instances, most notably China, it is poverty-driven. Elsewhere it is driven by economic growth or profit motive. Also, population growth is not a discreet driver, it is itself driven by economic growth, religious and cultural practices, and poverty, oh and greater food production, to list a few.

My fundamental point is that we can no longer put all of our energies into improving efficiencies and increasing production without very carefully considering the ever-growing population, on all different levels, from local to global. If the ‘technofix’ brigade doesn’t consider the other half of the equation, they are just feeding [literally] unsustainability and an ever-more precarious world.

“I am very motivated about using technology and wealth to decrease water….. "footprints" on the planet.”

Good. But if each person’s average ‘footprint’ is decreased while the number of people continues to increase, what do we gain? In Australia, if we can decrease per-person water usage by say 20%, which will be an enormous achievement, and the population increases by 25%, which is due to happen in something less than 20 years, then we will have achieved nothing. David, even your best water conservation and efficiency measures are due to be cancelled out and overwhelmed in a pretty short timeframe. What will we do then? Unless of course we deal with the continuous human expansion factor, head-on.

“In my view industrial ecology,….. is crucial to good planetary stewardship….”

Yes, but not in isolation. In isolation it just feeds this continuous growth spiral, which takes us further away from sustainability and more into peril.

(continued)

What I really object to is the lack of a holistic outlook here. I’ve seen this a million times with well-meaning technological thinkers.

David, your opening sentence expresses the enormity of continuously increasing demand for agricultural produce, but from then on you just pander unquestioningly to that endless increase. I thought that was terrible, but now it seems even worse: You have downplayed the effect of population and economic growth…… and yet you talk about ecological footprints. I think there is a major point of confusion here in your thinking.