Luckily, there are people here who care about our environmental problems and who are setting good examples and setting up recycling enterprises.

I admire their enthusiasm, but what is required is the concerted effort of all citizens. There has to be more education on the part of the government, and it should target young people with talks in schools.

It should also be looking at ways of further developing renewable energy, such as solar power, so there is less reliance on coal. But it is not just up to the government. All citizens should be trying to recycle more and waste less. We should only purchase as much food as we need.

Fok Pui-yi, Tseung Kwan O

Demand will be limited for recycled glass

Earlier this year, the Legislative Council passed an amendment bill imposing a levy on glass bottles from 2018.

I do not think the government has a comprehensive policy on dealing with municipal solid waste or on recycling.

Recycled glass can be turned into bricks, which can be used, for example, on pavements, but there may only be limited demand for them in Hong Kong. Factories making them might not need all the glass ­bottles available for recycling so many will still end up in landfills. Some may be transported to the mainland, but that just shifts the waste problem north of the ­border and causes problems there.

Years ago, manufacturers of, for example, milk, soy milk or soft drinks would collect their glass bottles and reuse them. However, many later switched to plastic containers as it is more convenient. Refilling is not feasible for bottles that are ­imported, but collection schemes for refilling could be ­revived by local manufacturers.

They could coordinate with retailers who should recognise they have a social responsibility to collect these used glass bottles so they can be refilled and reused.

Citizens can also reuse these bottles as vases and water bottles. Residents, the government and companies should all be trying to think of ways to ­improve the environment.

Felix Mak Hoi-kuoh, Kowloon Bay

Carbon dioxide reduction only partial solution

I refer to the letter by Lee Sai-ming, of Hong Kong Observatory (“Established laws of physics used to make climate projections”, August 4).

Regarding the second edition of the Observatory’s “Hong Kong in a Warming World”, I have issues with parts of section eight – “Climate Change in Hong Kong”. A better indicator of annual mean temperature trends in Hong Kong is to use the mean annual value of all 40 temperature stations available from the Observatory’s website over time so that rural stations are also taken into account.

The 1885-2015 record of the Observatory’s headquarters station is not only severely ­affected by the well-established urban heat-island effect found by many researchers, but also influenced by some of the lowest annual mean temperatures when records began, an aftermath of Indonesia’s Krakatoa volcanic eruption in 1883.

The 145.5mm hourly rainfall record in 2008 is best explained by the spread of aerosols arising from the May 2, 2008 eruption of the Chaiten volcano in Chile. Satellite remote sensing records support this claim.

The annual mean sea level at Victoria Harbour in section 8 is obtained by combining the tide gauge records of two stations (North Point 1954-1986 and Quarry Bay 1987-2015), both located on coastal reclamations instead of bedrock. This casts doubt on the ground stability of the sites and suggests possible ground settlement. The dramatic sea level rise of 29cm from 1987-1999 recorded by the Quarry Bay tide gauge but not found in other Hong Kong tide gauges support this claim. ­I accept the laws of physics, but logical scientific conclusions supported by the best evidence are needed to enable us to interpret past climatic records.

Based on the absence of correlation with the increasing level of carbon dioxide of about two parts per million each year, ­carbon dioxide reduction alone is not the solution to human-induced climate change.

Wyss Yim, Pok Fu Lam

Figures show strong backing for extremists

I refer to the letter by Siddiq ­Bazarwala (“Anti-Muslim ignorance helps terrorists”, August 7), replying to my letter ­(“Millions of Muslims back ­Islamic State”, July 27).

Your correspondent claims I misrepresent research on Muslim opinion with “vitriolic and anti-Muslim” rhetoric and promote “false narratives”. In short, I’m an Islamophobe. Not so.

It is important to have a good grasp of how many support extremist ­Islam. Is it less than 0.1 per cent as Mr Bazarwala claim, or closer to the figure I quoted, “a minimum of 63 million”? The short answer is that I am right.

We both accept the Pew Research figures of the percentages which view Islamic State (IS) favourably.

The 63 million figure came from Harvard ­history professor Niall Ferguson. I fact-checked his figures (per cent times population) and confirmed them ­(tinyurl.com/support-for-Isis).

Mr Bazarwala simply ­quoted a Pew sub-headline to its study, “Muslim views of ISIS overwhelmingly negative” across the Muslim world.

At least 63 million Muslims in 11 Muslim countries support IS. Worldwide, well over 100 ­million do so.

It is certainly not “less than 0.1 per cent” of the Muslim population as ­Mr Bazarwala claims, but more like 10 per cent. This fact should be of grave concern to us all.

Why should Islam alone be immune from examination and why call critics “Islamophobes”? I can criticise the pope without being called a “Cathophobe”. Or make fun of ­Mormons (Book of ­Mormon)without being a “Mormophobe”. But I can’t point to wide support for IS without being a ­“vitriolic, anti-Muslim” Islamophobe?

Moderate Muslims must ­address Islam’s nastier doctrines and practices.

Non-violent Muslims who don’t do so, when their violent co-religionists wreak havoc, are not “innocent” bystanders. They are culpable bystanders.

Peter Forsythe, Discovery Bay

Wrong to call Sun Yang a drug cheat

Australian Mack Horton, who at the Rio Olympics won gold in the 400m freestyle beating Sun Yang by a split second, called Sun a drug cheat.

I decided to read about Sun’s infringement and find out why he was allowed to participate in the Games if he had been found guilty of being a drug cheat.

I read an article in Time ­magazine which explained that Sun had heart problems and took medicine which was on the list of banned substances for only five months but was then removed.

Sun was cleared by Fina, the world governing body of ­swimming, to compete, so it is obnoxious for Horton to refer to him as a drug cheat. The Western press has adopted the same attitude, ­calling him a cheat.

I can only shake my head over the viciousness of the Western press towards China, and yes, it’s happening again. The Western media is now ­asking if China’s women’s ­artistic gymnasts are underage, as they are so small.

Li Kwong Cheah, Calgary, Alberta, Canada