Past practitioners dressed their liberty-robbing theories up in religious or political mysticism, today phoney science is used. The goal remains the same, to deny general prosperity to honest working ­people seen as unable to know what’s good for them, and who feel they must be governed by their ­so-called betters.

DiCaprio doesn’t use crowded public transport or turn off air conditioners on a private jet or a monster yacht he hired, why should ordinary citizens? You are just as good as he is.

Particularly disturbing are the references to government action made by your correspondents. Authority should never be used to roll back human ­advancement to further any individual agenda. But if people really do believe in the ridiculous nonsense of climate change and want to do something, picket all the theatres showing ­DiCaprio movies ­insisting they turn off air conditioners.

Dave Long, Edmonton, Alberta, Canada

Get walking to help create a greener world

In many societies throughout the world, there is still insufficient infrastructure to ensure greater environmental protection, especially in developing countries. Lots of meetings are held to ­discuss making the necessary improvements, including the Walk21 Hong Kong Conference last year which discussed ways of making the city more ­pedestrian-friendly.

If people can walk to places more frequently, they will use less public transport and fewer private cars, and that will help to reduce emissions and roadside pollution.

This is not only good for the environment, but also for ­people’s health. It is important that we all walk more frequently.

One way to make this possible would be for the government to ensure that more pedestrian streets are planned in each of Hong Kong’s 18 districts. This will encourage citizens to ­develop the habit of walking regularly.

Athena Yip, Kowloon Tong

Tree health still not a top priority in HK

Not enough attention is being paid by the government to ­ensure the preservation of Hong Kong’s oldest trees.

Some of these older trees are neglected and either the whole tree or part of it collapses. For example, a falling branch from a wishing tree in Lam Tsuen ­injured someone a few years back. The trees are particularly vulnerable in bad weather, amid strong winds and heavy rain.

The government has to do more, including undertaking more regular checks, and it has to raise awareness about the need to protect and preserve our ­oldest trees for future ­generations.

Ng Tsz-wing, Tseung Kwan O

Liver donor’s display of heart rare in our city

I admire the woman who donated part of her liver to enable a mother to have a transplant.

The transplant patient’s daughter was not allowed to ­donate part of her liver, as she was still below the legal age of 18.

I really admire the courage of the 26-year-old donor, Momo Cheng, and the decision she made to save someone’s life.

Although this was a live ­organ donation, more citizens must sign up for the donor ­register so that their organs can be harvested after they have died and save lives.

The number who have done this in Hong Kong is still low, ­because of the traditional belief, especially among the older ­generation, that the body should stay intact after death. It is difficult to change this mindset, but I hope it will happen.

The government must do more to promote the organ ­donor register, make citizens more aware of the need to sign up and clear up the misunderstandings that persist.

They need to realise that by joining the register they can help to save patients’ lives.

Koey Shum, Wong Tai Sin

Sevens tickets system makes event elitist

Much has been said in your newspaper about the Hong Kong Sevens and, if it represents a very narrow section of society, should the city be hosting it.

My own view is that it is an important event that is ­conducted in a very sporting and convivial manner, but it needs to be more inclusive.

Many of the tickets are ­complimentary, given to the sponsors and well-off companies who invite their clients. ­However, many of these clients may already have a ticket and so don’t use the complimentary one or simply don’t attend the Sevens weekend.

Any claims by the Hong Kong Rugby Union that the event itself was a standout success should be tested against the 60-65 per cent occupancy rate that one could see on Saturday and ­Sunday. Even the corporate boxes were very thinly attended.

Allocation to companies should be cut and tickets should be sold by ballot to residents of Hong Kong, in the same way that tickets are auctioned every year for the Wimbledon tennis championships.

That would be the best way to address the right perception that the event is too elitist and does not represent the Hong Kong community at large.

Rahil Ahuja, Repulse Bay

Working out, music make for better sleep

People are so busy at work in Hong Kong and usually under so much pressure, that they often do not get enough sleep.

Doing aerobic exercises ­before going to bed might help them fall asleep more quickly and prevent insomnia.

Also, they can listen to ­relaxing music which helps ­relieve the pressure and make it easier to fall asleep.

People will enjoy a better quality of life and a healthier diet if they get enough rest at night.

Carmen Wong Ka-man, Kwai Chung