Mr Yim mentioned his publications posted on ResearchGate.

An examination of his ­climate-change-related articles posted on the academic ­networking platform revealed that about 75 per cent of the ­materials quoted did not show any indication of having been published in peer-reviewed journals.

The rest of the articles provided no counter-evidence of human-caused climate change.

Instead of making his views known to the scientific community through peer-reviewed journals and informed discussion, Mr Yim prefers to use these columns to make his claims.

Your readers are also invited to take a look at two Observatory blog articles posted on ­ResearchGate (on “climate alarm bells” and “scientific consensus”)for more details about the consensus view reached by climate experts worldwide on the subject.

S. M. Lee, senior scientific officer, Hong Kong Observatory

Self-control on smartphones vital for teens

I recently watched a video on the BBC news website about our ­increasingly wireless world and how it affects us, particularly young people from what is known as the iGen generation – those born between 1995 and 2012.

They are the first generation to have had a smartphone for their entire childhood, and for the older ones, their adolescence.

While this has brought some advantages, as the video points out, many of these young people rely on sending texts and don’t hang out with friends as much.

Some become isolated and can be victims of cyberbullying. This can lead to higher rates of depression among youngsters.

Parents need to get their children to practise self-control and reduce the amount of time they spend on their smartphones.

There is an app called SelfControl, which blocks certain websites or apps for a set amount of time. Installing this app on their phones could help teenagers to ­concentrate better on their ­studies.

I hope my fellow teenagers can appreciate there is a downside to new technology and they have to take care. They should try and keep in touch with friends by meeting up with them rather than sending texts.

Jenny Sit, Tseung Kwan O

Kim should be easing plight of his people

The country remains very backward. Despite this, Kim continues to develop more powerful weapons. His aim is to use these missiles as a ­bargaining chip with the West.

Either he is unaware or does not care that, even as he spends a ­fortune on his military, many of his citizens do not have enough to eat, and some suffer from ­malnutrition.

Because of his actions, Kim faces even tougher sanctions from the international community. If he continues along this path, it could have serious repercussions for his country and his regime.

What North Korea really needs is a government that sees economic development as its priority and seeks peaceful ­solutions to military issues.

Howard Lau, Ma On Shan

Negotiations are far better than sanctions

There have been calls for further UN sanctions following North Korea’s latest nuclear weapons test, which it claims was a ­miniaturised hydrogen bomb.

Sanctions will not deter North Korea from developing nuclear weapons, but actually make the regime more determined to do so. If it caved in to sanctions, this would make the country seem weak, and so its leaders will not do that.

It is the same situation in Russia. Sanctions against Moscow have not caused its troops to withdraw from the Crimean peninsula. As a political strategy, sanctions are not effective.

The crisis in the Korean ­peninsula can only be resolved through negotiations. US President Donald Trump has threatened military force, but that is not a realistic solution.

The US and UN should end their sanctions and persuade North Korea to get back to the negotiating table.

Billy Sit, Tseung Kwan O