The government may have recently convinced the ACT Civil and Administrative Tribunal that it has a ''solid scientific basis'' to kill kangaroos, but in the court of public opinion the jury is still out. The government has yet to prove that killing kangaroos is making a difference to the biodiversity that endangered species depend on.

It is concerning that, for the past four years, the ACAT, the Commissioner for Sustainability and the Environment, and indeed the RSPCA ACT - all of which are meant to have independent voices - have not held the government more accountable for its ''cull the kangaroo'' policy, which is based on incomplete and misleading science.

It is very likely we are killing kangaroos unnecessarily. And the government is too stubborn to change course.

Philip Machin, Wamboin, NSW

I have a great idea for undermining and eventually dismantling a national institution, one that delivers mail to everyone, five days a week, for a fixed charge.

Fewer people are using the service, so let's stop delivering every day. Now watch as usage of the service drops like a stone. No more birthday cards or anniversary cards or sensitive mail, or at least a big reduction as there is a risk that everything will take longer to arrive.

Presumably Express Post ceases too - or perhaps Australia Post hopes to replace a service that is now provided every weekday with another at 10 times the price.

Daily delivery is Australia Post's universal service obligation, and the service that sets it apart from its competitors. But setting aside for now that this is a government service and not a private sector business, it is not unusual for one arm of a business to be profitable and another loss-making. Given they are closely linked, in the absence of a daily letter delivery the profitable parcel service will surely leak to the competition.

Peter Marshall, Captains Flat, NSW

The spate of letters to the editor concerning the light rail from Gungahlin to Civic indicates that there is something seriously wrong with the reasoning or the calculations.

On one hand we have Bob Nairn, a highly respected traffic engineer who says that the proposal is non-economic at this point in time and freely discusses his modelling methods; on the other, we have Simon Corbell, who says the project is a goer but who refuses to divulge any of his experts' modelling. Neither explains why there is a need for a light rail system between Gungahlin and Civic.

Surely the cart is getting way ahead of the horse.

To me it seems that there is a limited number of jobs available in the Civic precinct - either now or in the foreseeable future. How many are filled, or will be filled, by people from the Gungahlin district? Surely there is data available (or can be reasonably estimated) on how many bus passengers and car passengers travel to Civic five days a week from Gungahlin.

Please don't insult the community's intelligence by talking about pie-in-the-sky future populations along the tram route. Even the simplest assumptions - for example, fares of $5 a day (to compete with cars) and five days a week for 48 weeks per year - show that it would require at least 42,000 Gungahlinese to yield an 8 per cent profit - let alone the operating costs.

Since the total workforce in Civic/Braddon is about 40,000 then the whole scheme seems to be a nonsense.

Neither of the political parties have told us what their traveller estimates are. So why is a tram even being considered?

Come on, Shane Rattenbury, stop hiding behind Simon Corbell and give us some honest answers.

Baden Williams, Lyneham

Graham Downie's concern about the cost of solar energy (Letters, June 18) is out of date because the price of photovoltaic modules has fallen by three-quarters over recent years. The 2013 Australian Energy Technology Assessment, available from the website of the Bureau of Resources and Energy Economics, shows that wind and PV are competitive with new-build fossil fuel power stations.

Nearly one-quarter of world electricity production now comes from renewable energy. Last year, half of new electrical power capacity around the world was hydro, wind and PV. Wind and PV constitute nearly all recent Australian power capacity additions. Rooftop PV systems grace the roofs of 1.3 million Australian homes.

With completion of the Snowtown wind farm in South Australia, wind and PV increase to 40 per cent of that state's electricity production. South Australian prices and grid reliability remain stable.

The ACT government's plan for 90 per cent renewable electricity by 2020 - mostly from wind and solar, is on track - and few people will notice because prices and grid reliability will remain stable.

The Australian Renewable Energy Target of 41 TWh by 2020 allows wind and PV to compete with old-build sunk-cost coal plants even in the absence of carbon pricing. The RET is driving down both wholesale power prices and greenhouse gas emissions. It will help achieve 100 per cent renewable electricity in Australia by 2040, with wind and solar replacing existing coal power stations as they reach the end of their working lives.

Professor Andrew Blakers, director, Centre for Sustainable Energy Systems, Australian National University

Regarding the article ''Nine minutes extra a day: PS stoush looms'', June 19, p1), some of us can remember being told in the 1980s and early '90s that the ''age of the computer would mean more leisure time because computers would make our work life so much simpler''.

Rather than working longer we would be working ''smarter'', which would equate to fewer hours of work per week. We would also be working from home and going into the office (which would be paperless) a few days a week at the most.

The suggestion was that there would be a shortage of leisure facilities (for example, libraries, swimming pools, golf courses, bowling greens) for workers to enjoy during the hours they no longer had to spend working.

What happened?

Malcolm Paterson, Greenleigh, NSW

Senator Zed Seselja is among the scientifically illiterate Coalition members who are blindly supporting proposed cuts to the CSIRO and other key research institutions to help bring the budget back to surplus. But what good is a surplus that holds Australia back from keeping pace with the innovations that are needed to create future jobs and exports?

Our competitors in Asia and elsewhere are pouring resources into their research, technology and engineering sectors and are already leaving us behind in many key areas.

We will remain a quarry and a farm needing to import advanced technologies because we will not have the skills for anything beyond basic manufacturing. The fact that the Coalition doesn't even have a minister for science shows the Abbott government is stuck in yesterday's economy.

So dire are the consequences of falling behind in scientific research that Coalition MP Dr Dennis Jensen, himself a former scientist, has openly criticised the lack of a coherent strategy for future innovation.

There have been many excellent articles in The Canberra Times highlighting the stupidity of cutting scientific research, and if Senator Seselja has not already done so, he should urgently read them. But he needs to do more. He and other Coalition MPs need to speak with Dr Jensen about what has to be done to prevent Australia from becoming a backwater economy.

Senator Seselja and other MPs should then follow Dr Jensen's example and put the national interest before party loyalty. Not doing so is the height of stupidity.

Suzanne Jedryk, Griffith

When hijacked, the thing you don't want in your hand luggage is an Israeli passport. For decades it has been the case that Israelis are the most likely to be treated badly by terrorists. Israeli hostages are likely to be shot first and released last.

George Brandis' decision to reclassify East Jerusalem as ''disputed'' rather than ''occupied'' has signalled to the world that Australia backs Israel in its territorial claims (''Palestinian head slams government's refusal to call West Bank occupied'', canberratimes.com.au, June 18).

Tony Abbott would prefer to call it a ''terminological clarification'', but the Islamic world probably won't bother with such niceties. They will now consider Australia to be Israel's best friend and consequently one of the Islamic world's worst enemies.

Arab governments have already responded by threatening trade sanctions. But the consequences to ordinary Australians could be more serious - even fatal.

Peter Greste's chances of being acquitted by an Egyptian court have probably diminished since Brandis announced the change. And henceforth, when hostages are seized by Islamic terrorists (such as ISIL), those holding Australian passports are likely to receive worse treatment than when their government was more neutral in the dispute.

Mike Reddy, Lyons

Contrary to the assertions of Owen Reid (Letters, June 17), Tony Abbott's US visit seemed to fit closely with my characterisation of his overseas travels as lacking in ideas and replete with symbolic rituals.

Abbott himself is not claiming any great achievements in the US, and after his meeting with President Obama, said only that, on climate change for example, they were ''substantially on the same page'', which doesn't exactly sound like a resounding success.

Other parts of his US visit were entirely unremarkable. Whatever Kim Beazley might have said, he was merely doing his job for the Abbott government.

Trevor Wilson, Holder

P.M. Button (Letters, June 17) joins Zoltan Kovacs in railing against the negative, narrow-minded and insular correspondents to The Canberra Times letters columns and thinks it's a shame that ''we prefer to knock, rather than support, our government in achieving the mandates it was handed at the election''. Mandates? What mandates?

Oh, you mean the mandate for bringing back knighthoods, no? Or do you mean the mandates to not raise university costs or to not change pensions? Is it the mandates to leave the ABC alone, or to not jack up medical costs?

No again? In that case, you must mean the mandate to fix the non-existent ''budget emergency''. Ahh … I knew I'd get it if I tried long enough.

Bronis Dudek, Calwell

P.M. Button (Letters, June 17) is quite right about some of the qualities of The Canberra Times letter writers. Some of them are ''narrow-minded'' and ''insular'', but they come from all sides of politics, not only from Labor supporters.

I can't remember Button writing any letters complaining about those who unfairly criticised the Rudd-Gillard governments, but perhaps he did. Nor were there many letters demanding that the former Opposition put aside its policies and embrace everything proposed by Labor, as Button suggests we should all do now.

As for Canberra Times correspondents ''deriving their income from the public purse'' and having ''little experience of life beyond the ACT border'', perhaps Button would like to explain the clairvoyance that gives him this ''knowledge''.

The fact is, the ACT has the most highly educated voters in Australia. Could this be why most Canberrans supported a republic and usually vote for left-of-centre parties?

Steve Ellis, Hackett

I have been impressed by the articulacy and sound arguments being advanced by Greens Leader Christine Milne compared with limp statements from the Opposition. But the Greens' best ideas come from renegade left-Laborites who have joined them.

If ever we gave the Greens government, could they be trusted?

Lotte Beaupipe, Dickson

I note that ACTEW Corp debt has increased 20 per cent in the past five years and will now exceed $2.2 billion. Some of this will no doubt translate to higher energy bills for Canberra consumers. One has to wonder just how much money is wasted by ACTEW on badly delivered programs like the Cotter Dam upgrade, inappropriate promotions and advertising, or excessive payments to ACTEW executives. One activity I have grave doubts about from a cost-benefit viewpoint is the use of helicopters to look for vegetation impinging upon their powerlines.

I also note the ACT government is also proposing the use of helicopters to look for illegal dumping. Your readers may be interested to know the small two-person Robinson R22 helicopter that I sometimes fly costs around 14¢ a second to operate. The larger helicopter ACTEW uses is likely to cost at least twice that, not including the cost of crew and observers.

Why doesn't ACTEW and the ACT government use satellite imaging, drones or a light aircraft with video to examine powerlines/dump sites, etc? After all Forestry are proposing the use of drones and British Petroleum will use them to inspect pipelines at Prudhoe Bay in Alaska. ACTEW's use of helicopters appears to be an expensive perk for some of their employees/managers or contractors.

Ric Hingee, Duffy

Tread warily at the gate, Carole Sladen (Letters, June 19), about the move of the Wig & Pen to Llewellyn Hall. Music in Canberra has suffered some very large hits of late and it has further to ebb. This is not an environment for purists. I'll place my faith in Peter Tregear, head of the Music School, to guide this process. And if a livelier arts precinct comes of this, I am pleased. At this time, music needs generous and flexible friends.

Eric Pozza, Red Hill

KANGAROO PROTEST

Re ''Vandals vent their anger on ACT depot over kangaroo cull'' (June 18, p1): one wonders on what side of the fence the ferals are on.

B.J. Millar, Queanbeyan West, NSW

MISTAKES OF THE PAST

Thank god the US has Barack Obama in the Oval Office as the problems the Coalition of the Willing left in Iraq come back to haunt him. At least this time around, Tony Abbott won't get a chance to do a John Howard because there is every chance Obama will not repeat the mistakes of the past.

D.J. Fraser, Mudgeeraba, Qld

WAR DEAD HONOURED

Ken McPhan (Letters, June 14) asks which countries honour civilians killed in war. The Netherlands does. I can assure him that there are many memorial sites in The Netherlands where those killed by the Germans in World War II, such as in razzias, revenge killings or those engaged in the resistance, are honoured.

M. Pietersen, Kambah

AGENT PROVOCATEUR

Is H. Ronald (Letters, June 16) employed by The Canberra Times as a sort of agent provocateur? I noticed two responses to his letters on June 18. What other correspondent gets up so many collective lefty noses? Keep up the great work, HR.

Alex Wallensky, Broulee, NSW

CORRUPTION INQUIRY

Paul McElligott (Letters, June 18) complains an inquiry into corruption at the big end of town involving ''colourful business identities, very large sums of money and the purchase of political influence for corporate or personal profit'' is not only newsworthy but long overdue. What about Eddie Obeid et al?

Greg Cornwell, Yarralumla

BRANDIS BEWILDERED

People should be kinder to Attorney-General Senator George Brandis, whose insights include that it is all right to be bigoted, and ''occupied'' actually means ''disputed''. It is possible that one of his overladen bookshelves fell down, and he was struck on his defenceless naked bean by a weighty Oxford Dictionary that got its pages scrumpled up. In either case, a Home for the Bewildered beckons, unless he is already in one.

Roy Darling, Florey

TRIUMPH OF EVIL

When will people like Brendan Ryan (Letters, June 18) get the message that sexual abuse in institutions is not only about offenders and their victims but also about people in power who cover up. As Edmund Burke reminds us: ''All that is necessary for the triumph of evil is that good men do nothing.''

Paul Kringas, Giralang

Email: letters.editor@canberratimes.com.au. Send from the message field, not as an attached file. Fax: 6280 2282.Mail: Letters to the Editor, The Canberra Times, PO Box 7155, Canberra Mail Centre, ACT 2610.

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