Since the Industrial Revolution, carbon dioxide in the atmosphere has increased by about 150 per cent. During this period a vast store of mineralised carbon from the earth's crust has been transferred to the atmosphere by combustion of fossil fuels, distorting the natural carbon cycle, and this is continuing.

The result is a rise in temperature. This is not manifest immediately in the year-to-year variability in the weather, but rather through the inexorable rise in decadal averages in temperatures, the heat content of the ocean and the melting of ice caps and glaciers. Natural variability is a consequence of the complex interaction of the atmosphere with diurnal, seasonal and latitudinal variations in radiation from the sun and the thermal properties of land and ocean, which in turn is affected by the slow moving currents. The progressive input of heat will affect these interactions and may well promote greater variability and extremes, but extremes alone are not an indicator one way or the other for climate change.

We have gained our present lifestyle and our understanding of the world through reason and the application of ingenuity and science, not through unreason and partisan thinking. That science is now telling us something unpalatable is no excuse. We now have the knowledge and means to imagine a different future and we owe it to the children in our care to get their future right, even if it costs us.

Trevor Powell, Bruce

It seems Dr Andrew Leigh is getting desperate for anything to criticise the federal government about (''Gungahlin Jets at centre of row over grants'', February 17, p5). Totally ignoring the successful strategy of turning the boats back under the very capable stewardship of Minister Scott Morrison, he is bemoaning the fact that the federal government will not give a grant of $65,000 to the Gungahlin Jets.

I am sure this sporting club is an essential part of the sporting fabric of Gungahlin, as are literally hundreds of other sporting clubs around the country. Perhaps Dr Leigh could strap on an apron and man a fund-raising sausage sizzle outside Magnet Mart in Gungahlin on a Saturday morning to help fund the shortfall. That's what amateur sporting clubs have done for decades, not race off to governments seeking a handout.

Brendan Ryan, O'Malley

A dire constitutional crisis in Australia resulting from Scottish independence, as envisaged by Harry Evans (Letters, February 15), is a chimera. It will never happen. In 1901 the Commonwealth of Australia was established ''under the Crown of the United Kingdom of Great Britain and Ireland''. The United Kingdom as so defined was dissolved in 1921. Its disappearance has had no effect on the legitimacy of the federal government or parliament of Australia.

Stephen Holt, Macquarie

Harry Evans's quote (Letters, February 15) from the Commonwealth of Australia Constitution Act 1900 (section 2) is misleading as it omits the context provided by the preamble that states that the Australian colonies, apart from Western Australia, which is not at this point mentioned, had "agreed to unite in one indissoluble Federal Commonwealth under the Crown of the United Kingdom of Great Britain and Ireland".

This description of the UK ceased to be accurate when Ireland secured its independence. Accordingly, in 1927, the British Parliament provided that "the expression 'United Kingdom' shall, unless the context otherwise requires, mean Great Britain and Northern Ireland".

Scotland is a component of the UK by virtue of being a part of "Great Britain", a term first used by King James, by proclamation, and later adopted in the Act of Union 1707, article 1. This usage was replaced in 1801 with the term, "United Kingdom of Great Britain and Ireland".

It is questionable whether passage of the Scottish referendum would mean dissolution of the UK or simply redefinition, as occurred in the 1920s. It would, however, certainly mean ''Great Britain" would henceforth refer only to England and Wales.

Thus, to argue that, as a consequence of a vote for Scottish independence, "major parts, if not the whole, of the Australian constitution will be inoperative", is to draw a very long bow.

J.R. Nethercote, Braddon

Chief Minister Katy Gallagher is quite right to hesitate before agreeing to support mandatory minimum sentences for serious sex offenders (''Gallagher considers sentencing petition'', February 13, p1) as these almost inevitably lead to gross injustices when less serious cases become the subjects of the new sentencing regime.

Ms Gallagher quite correctly declined to comment on the individual case which has provoked widespread public as it seems highly likely it will go appeal. I will also follow her lead. There are no easy answers here but the Chief Minister main gain some assistance from a report that I prepared for the ACT Government in 2006. That report ''Sentence and Release Options for High-Risk Sexual Offenders'', for which I was paid a modest fee, produced no formal response from the ACT Government at the time. Apparently, the urgency of the subject was overtaken by other political priorities.

An abridged version of my report appeared later in 2006 in The Australian Journal of Forensic Sciences and this also reviewed the steps taken in other Australian jurisdictions, including continuing custody or supervision well beyond the sentence imposed by the courts.

David Biles, Curtin

Most of the streets in Barton have two-hour parking and these are occupied continuously during the working day. It is rare to see a parking inspector. Why not remove these two-hour parking limits and allow all-day parking on Barton streets, but set aside some areas for shorter term parking and monitor these areas regularly so short-term visitors can actually find a parking space in the suburb during the day.

Bea Duncan, Barton

Nicole Lawder's suggestion to eradicate the very annoying koel on behalf of her constituents, (''MLA comes under fire for suggesting eradication of koel'', February 15, p3) prompted Simon Corbell to say was ''shocked'' , and that ''perhaps Ms Lowder may next want to eradicate the black cockatoo''. That was ridiculous. The black cockatoo is a beautiful bird, is native to Australia and does not make a noise that drives you insane.

Many people in Canberra who are victims of the koel's noise hate it. We had the misfortune of having a koel in a tree near our house for three consecutive summers.

This wretched creature may be native to northern Australia but is not native to Canberra. Only recently did it take up temporary residence here. It is a nasty bird, laying eggs in the nests of native species (whose eggs or young are often thrown out by the hatchling koels). The koel wakes before other birds, inflicting us with its horrible noise at 5am - it must be one of the most annoying bird noises in creation, on par with the peacock. As Ms Lowder states, Mr Corbell has turned this issue into a way to score cheap political points.

It is a nuisance, does not value add in any way to the environment and should be eradicated as suggested.

Alas, Mr Corbell will do nothing about it, so I suggest someone transfers one of these birds to a tree in his back garden so he can experience what it is like to live with it for five months of the year.

Judy Diamond, Narrabundah

Shell's decision a few years ago to have its fuel delivered throughout NSW by road rather than by rail has come home to roost (''Petrol runs low in NSW as Cootes' crisis grows'', February 18, p7).

What a stupid and costly decision.

Ken Eynon, Latham

Michael West has presented one of the best pieces yet on LM Investments (''Money was moved to partner as LM failed'', BusinessDay, February 17, p7). The fact that Peter Drake and other directors presided over the destruction of some $1 billion of investors' funds and yet to date have not been bankrupted or prosecuted is a disgrace.

To rub salt into the wounds, Drake continues to run a business and live a high and comfortable lifestyle, while many self-funded retirees lost their life savings. Once again, ASIC has failed to do its job.

It is time the government demanded that it does the job it was set up to do. In this regard, it is pleasing to see that Nationals senator John Williams is intent on pursuing ASIC's failings and fixing them. It is to be hoped that he gets the support of the responsible ministers in doing so.

Peter Langhorne, Narrabundah

When is the Prime Minister or the Attorney-General going to set up a royal commission on the activities of lobbyists and big business? The perceived unconscionable behaviour of the transport, food and beverage industries, to name but a few, in exerting undue influence on governments is reprehensible. Surely their activities are just a sophisticated version of the bribery and corruption schemes attributed to the union movement. No organisation should be exempt from being put under the spotlight if we are to live in a fair society.

Judith Shaw, Macquarie

I concur with Anne Laisk (Letters, February 17) on Commonwealth Bank charges. I asked staff to cancel a money card. They converted my money to euros, even though I can use the card in Australian dollars. I should have just used the card in Australia and spent MY money, as it has cost me more than $100 in exchange rates. I was also not advised that there is a complaints resolution process at the bank. The customer, without whom financial institutions would not exist and make massive profits, is just the pawn.

Steven Hurren, Macquarie

As a buyer of goods from overseas, Anne Laisk (Letters, February 17) has been surprised by the bank fees charged just to move money. As a seller of goods, I recently sent a set of pivot hinges to a chap in New Zealand. The cost to me to move his money across the ditch was half the value of the goods and double the cost of the postage. It would not surprise me if the rampaging elephant was charging both buyers and sellers $22 each for the same transaction.

Howard Styles, Yarralumla

The Liberals promised to retain the renewable energy target but have just appointed a climate change sceptic to a review with the following terms of reference: ''Provide advice on whether the objective of the RET scheme, to deliver 41,000 gigawatt hours … is still appropriate [and] … implications of projected electricity demand for the 41,000 (GWh) target.'' Personal efforts, motivated in part by environmental concerns, have contributed to reducing electricity demand since 2009. Consequently the promised target could result in more than 20 per cent renewable energy by 2020. This should be cause for celebration and the closure of a few coal power stations. Instead Tony Abbott seems likely to mock our efforts by cutting the target while giving the appearance of keeping a promise.

Peter Campbell, Cook

If Australia has an oversupply of green energy, does this mean that nuclear power is off the agenda for the time being?

S.W. Davey, Torrens

Alan Shroot's is a copybook - overstretched and pettifogged - defence of the creeping real estate enterprise that Israel has been for so long.

Were there not the (uncomfortably ethnic) repression, radicalisation and impoverishment that exists in Israel's growing First-World shadow, I might wryly admire the artifice and straight-faced audacity of the case that Mr Shroot and other Zionists have workshopped to

de-putrefy the strikingly asymmetric border and settlement grabs that the Palestinians are utterly powerless to contest.

Sadly, it doesn't much matter what those of Mr Shroot's ilk advance as arguments in defence of whatever resumptions, imposts, regional plays, and general mendacity issue forth from Tel Aviv; the lock-step of numerous foreign ministers rallied by the United States ultimately relegates all public argument to so much wasted breath.

Israel will have its way.

Ross Kelly, Monash

The intimation by Ian De Landelles (Letters, December 17) that ''the government, in fact, wants potential asylum seekers to believe they are indeed in significant danger of being mistreated by those charged with keeping our borders safe … and is a higher priority than clearing the reputation of the navy men and women who are carrying out the orders of their political masters'' is probably one of the most despicable and denigrating proposals ever voiced in the letters section.

Not only does it cast a monstrous slur against the popularly elected government but it also, by default, suggests that the navy was guilty of the inappropriate behaviour so readily broadcast and belaboured by the ABC.

N. Bailey, Nicholls

The recent rise of the unemployment figure to 6 per cent (''Rising jobless rate surprises Coalition'', February 14, p4) poses the question: how much weight should really be given to the unemployment figure? It's a percentage of people not working as compared with the number who say they'd like to work - which, of course, can include people who don't really want to work but say they do for various reasons (and thus are not really unemployed).

R.S. Gilbert, Braddon

REBELS WITH CAUSE

I send my solidarity and support to the brave freedom fighters on the Manus Island concentration camp resisting the crimes of the Australian government. It is right and just to rebel against such tyranny.

John Passant, Kambah

TAXING TIME FOR PUBLIC

I refer to Ben Butler's article ''Rupert Murdoch tax win blows $880m hole in federal budget'' (canberratimes .com.au, February 17). Those fond of ranting against ''the taxpayer-funded ABC'' are now free to celebrate the windfall of the taxpayer-subsidised (and American-owned) News Corp.

Peter Grabosky, Forrest

TRIATHLON A SUCCESS

A big congratulations to all children who competed in the Weet-Bix triathlon at the Australian Institute of Sport on Sunday. It was wonderful to watch my two nieces and the other entrants compete. I hope there are more events such as this to inspire our youth to enjoy sport.

Margaret Tuckwell, Aranda

ILL AT EASE WITH COST

Initial prescription dispensed at discount pharmacy in Woden for $11.89. Repeat dispensed at pharmacy in Civic for $20.40 (identical non-generic drug). I know who won't be filling the next prescription.

Helen Arch, Garran

PLAN FOR INVASION

China is not limiting its predation to the China Seas (''Mega-sized fish factory trawler in the Pacific'', February 17, p3). The equivocal denials by the ship's owners in Hong Kong are unconvincing. The converted tanker and its attendant fleet of trawlers are a capital resource that will seek maximum return. Australia needs to have in place a firm plan for when its waters are invaded by such fleets.

Gary J. Wilson, MacGregor

STOP WHINGEING

I suggest it is a very old furphy to slight the post delivery (Letters, February 17) and that problems are widespread. Our experience is of timely mail deliveries made by cheerful posties and parcel post. As well, the services in the Australia Post shops are also cheerful and very helpful. Let's stop the whingeing!

Marguerite Castello, Griffith

SPRINT SPECIALIST

Jack Pennington (Letters, February 14) compares the performances of Melissa Breen and Betty Cuthbert, which is difficult as Melissa is a specialist sprinter concentrating on the 100 metres while Betty was a more diversified sprinter - 100, 200 and 400 metres. Also, Melissa has yet to have the opportunity to compete against international sprinters.

Dave White, Deakin

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