Contaminated stormwater caused by run-off from streets, houses and development blocks is increasing as the proportion of hard surface areas rises in modern Canberra.

Nutrients from leaf litter entering the drainways is probably the largest contributor to the problem and causes algal outbreaks in the lakes.

Having observed the huge quantities of leaf litter clogging a multitude of street gutters and drains in older Canberra suburbs and the reluctance of most residents to act themselves, I would suggest a fleet of mechanical street sweepers in daily action would make an enormous contribution to reducing the problem.

I recall seeing one go past our place a long time ago.

John Mungoven, Stirling

‘‘Scientists dig deep for missing piece of climate puzzle’’ (January 27, p18) is a lucid lay explanation of complex Antarctic research into atmospheric greenhouse gases other than carbon dioxide.

The research has profound implications for predicting the course of climate change, for better or worse. Oh ... and for finding possible hidden traps in hydrogen as a new clean fuel. Thank you, Peter Hannam, for the article, and CSIRO for the Australian research contribution.

John Young, Isaacs

On Australia Day this year (Panorama, January 27, p2) Ian Warden quotes a Bruno Latour. He is a noted French sociologist of science, with chairs at the LSE and Cornell, no less.

Latour has a theory that our ‘‘talking-about-anything-but-climate-change has been conspiratorially engineered by cunning elites’’. We are easily being distracted by things like Facebook and Brexit, he argues.

I like the way Warden then challenges us ... ‘‘Have you said anything or done anything about climate change today?’’ he asks. I like it because for some months I have been telling my patient friends that we should refuse to greet each other with anything less than big-picture observations about the plight of our planet. Only then should we allow ourselves to move on to matters particular to us as individuals.

I have even threatened to start a sect whose rules I would establish along those lines. And it’s not just conversation that would be shaped by my sect. I would be emboldened to have rules of dress, like Scott Morrison, but they would be more profound. I would encourage members to purchase T-shirts like the one I bought recently that reads: ‘‘Killing the planet is against my religion’’.

The wearing of such a message has become an excellent way to avoid the conversational distractions so aptly described by Ian Warden and Bruno Latour.

Jill Sutton, Watson

Congratulations on the front-page article (January 20) comparing petrol pricing. In our present financial system, competition supposedly keeps prices down.

However, if we look at banks, electricity companies, petrol and many other services, there is a transparent lack of competition.

Petrol, however, is the closest to our daily expenditure. If that industry cannot control its greed, there are ways to improve its lack of ethics. The first is price control. The second is to support independent service stations by ensuring they can operate freely as far as pricing is concerned.

At the moment we are discussing a form of price control on electricity distributors. If we can do that then we should also be able to apply that to petrol and diesel.

At present, most if not all of our fuel is refined overseas. This might well be a cheaper way to do it, but in the event of a conflict it leaves us with inadequate reserves, and that leaves us vulnerable.

Howard Carew, Isaacs

I wholeheartedly agree with Jim Coats’ letter of January 21 titled ‘‘No safe illegal pill’’, which echoed the sentiments expressed by R.Salmond and A.Richardson (Letters, January 17) regarding pill testing.

One wonders if these correspondents are aware that it is equally true that there is no safe legal pill either.

The number of adverse reactions, allergies, contraindications, interactions, side effects, dependencies, mistaken prescriptions, mistaken supply and what-not involving prescription medication causes more deaths, hospitalisations and expense to society than recreational drugs.

Gary J. Wilson, Macgregor

Max Brown (Letters, January 29) is missing the key point about water tanks and environmental flows.
Whatever our future population may be, people will continue to plant and water gardens — and there are genuine health and environmental benefits from doing so.

But, as gardeners will use a given amount of water on their gardens, it matters little whether they intercept it directly from their own roofs or take it, via the tap, from water intercepted by dams: the same amount of water is diverted.

If anything, given that dam water was already in the river system, I suspect that using it rather than tank water would be likely to have a more immediate, and possibly larger, impact on downstream flows – though any differences would probably be negligible in the long term.

So whether or not to install water tanks is surely a decision that may be made on economic criteria, knowing that downstream water flows will neither be helped nor harmed either way.

The only effective way to improve environmental flows is to reduce usage. In the case of gardening, this would include waterwise gardening practices and the treatment and use of grey water.

Felix MacNeill, Dickson

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