Like many people I believe humanity cannot continue to consume the world's resources at current rates. Forests, grasslands and ice-sheets are being destroyed, species made extinct, fish stocks depleted, air and water polluted.
But I get annoyed by simplistic or ludicrous "solutions."
One that annoyed me recently was the ABC's Ockham's Razor talk by Dr Ted Trainer.
I have no issue with the alarm bells he rings.
"We've far exceeded sustainable levels of resource use and ecological damage, especially in the rich world's taken-for-granted lifestyles," he says. "…..the amount of productive land used to provide for one Australian is about seven hectares. If the 9.7 billion people expected by 2050 were each to have that much, we would need almost 70 billion hectares of productive land. But that's almost ten times the amount available on the planet."
For other resources he says the average person in a rich country is also consuming something like 10 times as much as the poorest half of the world's people.
I agree with Dr Trainer's view that we must stop the quest for continuous economic growth, and ever increasing production and consumption.
I partially agree with Dr Trainer's view that technical advance will not solve the problem.
I don't think technical advances on their own will solve the problem.
But I do believe they are part of the solution.
And I strongly disagree with Dr Trainer's back-to-the-past "Simpler Way" solution.
He envisages highly self-sufficient, co-operative and self-governing local communities, using mostly local resources to meet local needs. The economy would have no growth and indeed a Gross Domestic Product (GDP) per capita that would be a small fraction of today's figure.
The economy he envisages could not be driven by profit, market forces or maximising output or wealth.
He thinks suburbs or towns could easily be restructured to become highly productive communities crammed with community gardens, fish ponds, forests, workshops, co-ops and small firms. There'd be many commons containing orchards, animal pens and community facilities, maintained mostly by community working bees and committees. The high level of local self-sufficiency would eliminate the need for most transport, enabling many suburban roads to be dug up and converted to gardens and farms.
Dr Trainer believes people would have plenty of time for their pottery work or novel writing.
To say that Dr Trainer's view is naïve is an understatement.
Such communities have never existed and will never come into being.
He also grossly under-estimates the resource damage 9.7 billion people living in such communities would wreak.
Take, for example, the little suburban pottery in each community of say 1000 people. This would amount to 9.7 million kilns burning huge quantities of wood. The surrounding forests would be devastated, not to mention the greenhouse gas emissions.
Or would we have coal fired kilns or kilns fired by gas or electricity? Where would the electricity come from? Perhaps mini-hydro or wind or solar power?
But the manufacture of solar panels requires highly sophisticate large-scale technology to produce the aluminium frame and the glass cover, not to mention the silicon cells themselves. To make a conventional polycrystalline silicon panel requires very pure semiconductor-grade polysilicon which is obtained from quartz in an electric arc furnace. High temperature treatment produces ingots which are then sliced using wire saws to obtain wafers, which are subjected to a surface etching process.
Try doing all that in your village.
There's no question that we in the rich world are consuming far too much of the planet's resources.
We can't ask poor people in the developing world to cut-back while we consume, consume and consume.
There are some obvious things we can do. New technology will undoubtedly help improve recycling and reduce waste. Cities and neighbourhoods can be better designed and public transport improved.
Surely something can be done about the obesity epidemic?
Defence spending must be curtailed worldwide. Vast quantities of resources are consumed by the production and running of military aircraft, ships, tanks and trucks; the firing of weapons; training and exercises; and of course wars. (We're going to squander $50 billion on submarines that will be obsolete when they're launched.)
This is consumption of real resources. Nothing productive is left behind, unlike spending on a railway line, a school or a hospital.
There are positives from the new economy that are not widely recognised that may play a part in maintaining employment.
We frequently hear a lament from environmentalists that we cannot maintain continuous GDP growth while economists tell us that we need GDP growth to maintain jobs.
What is often not recognised is that GDP is not a measure of real resource consumption. It is a monetary estimate of value added by producers in a country.
Its growth does not mean that more resources are being consumed.
Some examples illustrate this point. If you download an iTunes song you pay Apple and this sale adds to GDP. But you have consumed virtually no material goods.
Similarly if you pay Foxtel to download a movie, or Microsoft to download its software, you have consumed next to nothing. But you have generated revenue for Foxtel or Microsoft and this is counted in GDP.
We do not know what percentage of GDP is generated by trade in virtual goods, but sales have obviously increased over recent years.
The growing share of the services sector in the economy is also good news.
This sector now accounts for roughly 68 per cent of GDP worldwide. It includes personal services such as education and lawyers and accountants' fees, as well as wholesale and retail trade, transport and health care.
While transport and restaurants clearly consume goods, only a small proportion of the cost of some professional services is from the consumption of material goods. Lawyers charge for their brain power. Paper and consumables make up only a small proportion of their fees.
Another bit of good news comes from renewable energy.
Material goods are used in building a wind turbine, or solar panel but once built, a renewable energy generator consumes little material resources. But the sale of their electricity is counted in each year's GDP.
So it's not all doom and gloom when you hear the latest GDP growth figure.
The growth, and indeed a large proportion of GDP itself, may well be from sectors that consume next to no real resources.