Why is defence spending so often quoted as a percentage of GDP? Gross Domestic Product is not directly related to how much is available to spend. It is a rough record of profitable industry, that's all. The profits of casinos, which make their money by taking it out of punters' pockets, is included, as are other dubious "profits" that do not profit the nation.

If a real idea of how much we spend on defence is desired, you need to get it from the budget. For example, the 2019-20 budget reveals that we spent $32 billion on defence, which is 6.5 per cent of the total.

Two per cent sounds so much more affordable, and that is probably the reason it is used so much to define spending on defence.

Further to the proposals to build a National Convention Centre and a stadium in Civic which have been backed by David Pocock ("It's holding us back as a city': David Pocock backs Civic stadium complex", canberratimes.com.au, March 11) I would like to add a third major project for Canberra. A new national institution: a Natural History Museum.

Almost three years ago a Joint Parliamentary Committee report on Canberra's collecting institutions recommended that the government develop a business case for such a museum in Canberra.

It was an excellent recommendation but the government has yet to respond to this report and has done nothing on this recommendation. I am not surprised given the government's lack of policies and lack of action on our environment, our heritage and climate change.

This is not a new proposal. Such an institution has been proposed many times over many years and there is no reason why it should not happen.

Such a museum would engage and educate both Australians and overseas visitors. Having spent the past two months lecturing on the high seas, I can state that the one thing all overseas visitors want to see is our unique wildlife.

With the impact of climate change already being felt across the country, we need to take action on several fronts to protect the animals and plants that make Australia special.

The museum is just one of these initiatives. We know we need to act. What we need are the individuals and political parties who are prepared to take action and who care about our future.

My wife and I have lived in Canberra on and off since the mid-1960s. We saw Woden built, then Belconnen followed by Tuggeranong. We have seen so many new buildings constructed that I now cannot remember them all; they have been pulled down and replaced.

Back then our roads were the envy of Australia. Now they are getting close to the worst roads I have driven which are on Norfolk Island.

Malta's second island, Gozo, has the remains of an ancient temple including one wall. That wall is the oldest free-standing wall in the world. It pre-dates the Egyptian pyramids by 1000 years.

How were those ancient engineers able to construct this? I suggest our so-called engineers visit Gozo and discover for themselves the secrets of construction. Learn from history.

I had better not mention what we should learn about world dictators. Oops, sorry, I said I should not mention it but I did.

Why, oh why is Europe heading towards full-scale war, when it's bleeding obvious that Russia is historically a part of Europe, should have been welcomed into the European economic arrangements, and shouldn't have been isolated, no matter how irrational its leadership has become.

Smarter politicians might have remembered Churchill's advice that "jaw, jaw" is better than "war, war". Where are they? Macron, maybe, Biden, if he wakes up, but definitely not Johnson or Morrison and Dutton. God help us all.

Bradley Perrett's article "War highlights army's big mistake" (March 12, p43) makes it evident on the one hand, that he is an experienced journalist, and on the other, that he has never served in the military.

If he had, he would know that the weapon systems which are ideal when defending a locality, are very different to those which are ideal when attacking and securing an objective.

This being the case, it does not follow that Ukraine's successful employment of drones against Russian tanks makes Australia's intended purchase of Infantry Fighting Vehicles (IFVs) redundant.

Drones, for example, are unable to capture an objective, nor hold ground.

It is not feasible for modern armies to equip their forces solely for either defensive or offensive operations. Flexibility is one of the principles of war. Units operating IFVs must be adaptable as circumstances change.

It is not only tactics and force composition which will enable IFVs to counter the threat posed by drones in the future.

When fitted with Active Protection Systems (APS) IFVs will have an ability to destroy missiles and projectiles fired at them.

A big thank you to the Rolfe family for all the great work they do for the Canberra Community. ("Who is Zachary Rolfe?", canberratimes.com.au, March 12).

What a relief they must have felt when their son Zachary was found not guilty of the murder of Kumanjayi Walker, a young Indigenous man in the Northern Territory.

The question I ask is why did The Canberra Times feel it necessary to run this story at this time?

The Northern Territory painstakingly followed due process with the Supreme Court jury deciding correctly to dismiss the charges against Zachary Rolfe, thereby vindicating his actions on that fateful evening.

It is as simple as that. Any suggestion that justice has not been achieved is false.

As a constable, Rolfe appears a very special Australian and is destined for a grand future. It is a shame he was forced to endure that torment. If I was his father I would be very proud of him.

Perhaps it is now time, since Mr Morrison has admitted that "we are dealing with a different climate to the one we are (sic) dealing with before," that he also admits (a) that it is time to upgrade our efforts to minimise and reduce our greenhouse gas emissions and play our part in the global effort to reach zero emissions, and (b) that there is a need for a civil defence force, similar to the ADF and similarly funded by the federal government, to be established to alleviate the consequences of these events.

Perhaps it could be similar to the reserve that exists in the ADF; members to be trained to deal with the aftermath of fires, floods, and other extreme weather events, who continue with their "day jobs" but remain ready to be called upon when such events occur. This would involve, of course, a tax-free wage from day one in training, and increasing with time, experience, and rank.

The PM has announced that he intends to increase the numbers of the ADF, and it would be good if he would also announce the development of this CDF, since he is now recognising that this climate situation is not going away but is accelerating, and that heads must come out of the sand.

Thank you, Heather Nash ("Let's not forget Marsh", Letters, March 14) for reminding us of the cricket great Rod Marsh in our rush to lionise Shane Warne.

Not being a cricket follower by any stretch of the imagination, my knowledge of both players is limited. But I have been well and truly educated over the past weeks of their respective prowess.

Their untimely deaths however, followed so closely by Senator Kimberley Kitching, all at such a young age, makes us ponder on our mortality.

Wow. What a euphemism calling Russia's war of invasion in Ukraine a "special military operation" when it bears all the hallmarks of the war crimes and crimes against humanity that we associate with fascist and totalitarian regimes. Shame on those who describe the Russian war of invasion in that manner.

David Pocock wants to replace a functional stadium with a new, carbon-intensive concrete and steel structure ("Pocock backs Civic stadium complex", canberratimes.com.au, March 11). At least we now know the price at which he is prepared to walk away from his supposed principles.

As a result of the many delays attributed to our PM, should he be now known as "SlowMo"?

The only thing the government can take credit for responding to in timely manner is political advertising and electioneering.

As Peter Haddon points out, our army no longer wears khaki, but disruptive pattern camouflage (Letters, March 15). As a testament to the effectiveness of this change, I see on the news that they need to wear hi-vis vests for non-combat roles such as flood clean-ups.

While watching the PM fronting voters on the the Central Coast on Fox and Sky I had to switch to repeats of Rosemary and Thyme for some relief. Mr Morrison believes talking about the last Labor government will inform us of the future. Could he speak of his policies for right now and outline a vision for the future - if he has one?

Can someone please explain why publicity for Canberra Day events named Commonwealth Park as the venue when the festivities were actually held in the Parliamentary Triangle?

Millions of Ukrainians are fighting for their lives, their country and their freedom. Meanwhile in Australia people are upset the price of fuel has gone up. So what? Maintain a sense of perspective please.

Any petrol excise cut will be replaced by an oil company price hike. Think long term and replace the oil burners with green hydrogen powered fuel cell vehicles like the one shown in Toyota's advertisements.

It's a dilemma. If the fuel excise is cut petrol may be cheaper for motorists. However the Commonwealth will have less money in the coffers to assist the needy.

Given fuel prices soared almost simultaneously with the outbreak of hostilities in Ukraine I wonder how much fuel, presumably acquired at the lower price, was already in Australia at the time? I'm guessing these stocks are now being passed off to consumers at the inflated price. A case of making hay while the sun shines?

I look forward to seeing Putin in the dock at the war crimes trials. Bring it on.