Excellent, informative article. We are heading for a perfect storm of environmental disaster.

For the first time last week, I read in New Scientist that James Hansen has raised the possibility of a 'venus scenario' where Earth becomes permanently too hot for life, particularly human life.

Before that happens we have many opportunities to change the future, including the very important matter of how we grow our food.

And population overload is critical, but especially those of us who live in the highly developed, highly polluting, highly consuming world. We, too, must change.

I think this is an excellent reminder that we are all part of the same global systems, and plundering of one affects the next. Our only hope is to start some similary linked recoveries where we start to climb towards sustainablility not some illusion of global "control".

To use a farming expression, we humans are overstocked to buggery. More of us per acre than the soil can feed. There's a limit to the number of sheep I can run on my farm. With new technologies, I can tweak that up a bit, but not by much. If I exceed the limit, I am destroying my soil, my water supply, my pasture or the health and welfare of my sheep - or, more probably, all of them together.

The global population pressures, combined with the unwillingness of consumers to pay the true cost of sustainable food production, have resulted in the corporate farm, and all the sustainability and animal welfare issues associated with that, and in pressure on the remaining owner managers to push their farms and their livestock beyond the limit.

It isn't sustainable. Ask any dairy farmer down here in Tassie at the moment. Or any woolgrower. Or any graingrower, pig farmer, chook farmer etc etc. As the article implies, if we farmers don't farm properly in terms of the soil, water and the livestock/seedstock, the rest of it can only end, eventually, in tears. We can't farm properly and feed 7 billion people, let alone an increase to 9 billion.

I find it alarming that increasingly, the technical solutions to humanities’ woes are being replaced with social, political, moral and ideological responses.

Jonathan Foley starts off well by recognizing our fixation with non-technical solutions to climate change. Unfortunately he quickly replaces this with another fixation, “the global crisis in land use”.

The technical background to this I suppose is that we have too many people and agriculture cannot keep up. He also rightly points to the consequences of man made pollution and agricultural inefficiencies.

It is not unreasonable for a scientist to explore ways to improve our food production and to reduce pollution. What is unreasonable is for such eminent thinkers to keep boring down the same holes, in effect having reached rock bottom and started digging.

Some might suggest that more scientific effort should be invested in replacing agricultural production rather than stretching its finite capacity until it breaks. If we fail to do this we will keep returning to the same conclusion, if we cannot grow food production to meet population inflation then reduce the population. Any technical response is thus replaced by socio/political/religious solutions, contraception, sterilizations or one child families.

It matters not what type of scientist Jonathan is, what matters is that our scientific community needs to stop presenting problems and start producing scientific solutions.

Jonathan states that he worries “about this collective fixation on global warming as the mother of all environmental problems.” I worry that such eminent scientific intellect is wasted in the pursuit of consequences whilst remaining oblivious to causes or alternatives.

If traditional food production is a) limited by finite capacity, and b) causes environmental damage by forcing it beyond that capacity then he, as a scientist, is obliged to explore these causes and alternatives not the effects. Why are so many scientists regurgitating problems in such excruciating detail? When are our scientists going to get out of the socio-political domain and get back to their core function, science and the production of scientific solutions?

Dead cat bounce Jonathan

Jonathon is right about the strain on the present agricultural system.
However the present world population growth will have to stop and soon.
If not nature will do it for us, and it won't be pretty.

The lack of energy to transport food over long distances will come to
an end with the depletion of oil and gas.
The increased cost of the present industrial agriculture will bring
about its demise and I suspect it will be replaced by permaculture
techniques on local smaller scale farming.

This does imply a reducing population spread more evenally over the
country. Certainly the government should stop all immigration right
now as a matter of urgency. For goodness sake, I see in the media
that they are now distributing bottled water in Adelaide !
Is that right Michael in Adelaide ?

Has any one made an estimate of the cost of moving Adelaide ?