One of the biggest issues I think is chronic disease that comes with sedentary lifestyles in consumer societies, leading to huge healthcare costs. Evidence indicates that adding more medical care does not help in this case. We need to change our lifestyles. But this creates virtuous cycles of healing.

Perhaps we need to concentrate on neighbourhoods that are relatively self sufficient, so these might copy some of the qualities of the smaller cities I mentioned, and then the trick is connecting them all in the mega city regional arrangement. THis can bring some efficiencies. Some big cities like Singapore and Hong…

I have seen some amazing light filled "pavilion buildings' with light wells that go several stories down. But I don't think this is that significant in this discussion

My book is not about population disasters. In fact, I think we can have a better world with more people. But the book is really about a transformation from a materially obsessed culture to one where the emphasis is placed on our inner world and relationships, you might say a spiritual culture, one that can deliver…

W may be able to restore the natural world, but I think there will be a net loss of biodiversity what ere we do. But ecological function can be prioritized, leading to better incomes for the rural poor. I talk about an outstanding large scale example of this on China's Loess Plateau.

The first priority I see is for the top 20% of consumers to reduce their consumption—either through improved materials and energy efficiencies or outright reductions—by about 65%. In the low income countries, especially in rural areas where most extreme poverty is experiences, there is a potential to pay small farmers…

Well, we can look at 11 billion as too many people, or look at the population as huge potential to do things like reclaim deteriorated ecosystems. There are some 3 billion hectares of deteriorated ecosystems by some reckoning (se Rattan Lal) Restoring those lands, which would require a huge amount of work, would be…

My view is that we have to completely rethink, culture, politics, economy, travel, transport, everything. Local production will often, though not always, make more sense that transport. People seen something like $7 trillion a year of travel and tourism, about a tenth of the global economy. Discretionary travel will…

Yes, but let's not forget that the rate of increase in population is slowing. It follows the same trajectory everywhere, once women's rights are protected. Although, Iran presents an interesting case study, since its population growth has slowed to near zero at the same time that the Islamic revolution clamped down on…

As in above reply, watershed restoration increases groundwater recharge. Significant potential to increase access to potable water. Also, let's look at rainwater collection in urban areas. A generation prior to mine, everyone had cisterns to collect rainwater.

Some very interesting projects I talk about in ELEVEN, large and small, in desertified areas that make efficient use of water. When ecosystems are restored, watersheds begin to function properly again and ground water recharge occurs. Interestingly, improved ecosystems can even draw down added rainfall, as discovered…

Or should we look to places like Copenhagen, Helsinki, Amsterdam, with a dense form, active transportation, high creativity, high levels of social equality, efforts to reduce ecological footprint through efficiencies and renewable energy, experiments in job sharing, etc.

I think this is unrealistic at least until post 2100 period. Stephen Hawking believes that this our only hope for survival, I talk a fair bit about his view in the book. I am a short term pessimist and a long range optimist, we won't need to go to another planet, just reimagine this one as the home for all of…

No expertise on that topic, but it is only logical that crowding increases possibilities for transfer of disease. Of course, non-communicable diseases of lifestyle, like heart disease, are affected by urban form too.

Inflow to cities keeps increasing. Very interesting book on this called Arrival City by Doug Saunders. But because birthrates are high in rural areas, the total population will also increase, though not as fast as cities. I think we are moving to 60% or more urban.

You may have noted that there is a lot of action underway re restricting immigration. The ebola "crisis" may be used to stop emigration from crowded, poor areas. Actually, I just saw an article on growing crops in abandoned area. No, actually, Naomi Klein mentioned it in her new book THis Changes Everything. Abandoned…

Hope. Despair is a real threat, leading to nihilism. Just saw this quote this morning. "Nihilism is a natural consequence of a culture (or civilization) ruled and regulated by categories that mask manipulation, mastery and domination of peoples and nature."– Cornel West. By the way, you can follow my latest at Facebook…

They are doing that in the Gulf States. Very large ecological footprint I imagine. Though they look very beautiful from above, shaped like leaves.

That has happened already. Buffalo, Pitsburg, many industrial cities of the 19th and early 20th century are smaller than they were.

Again, go to Vaclav Smil's new book. Looked up the title. Making the Modern World: Materials and Dematerialization.