Caroline Lucas is right to say that climate change should be tackled with the utmost urgency, especially given Oxfam's estimate that 375 million people could be affected annually by climate-related disasters by 2015 ("Let MoD tackle climate, says Lucas", 26 September).

However, to shift responsibility for tackling climate change only to the Ministry of Defence would be to attack it from far too narrow a perspective.

Vulnerable people in poor communities around the world are already unable to grow enough food to eat or sustain their livelihoods due to increasingly unpredictable and erratic weather; dengue and malaria are spreading to higher altitudes because of warmer temperatures; and children are being pulled out of school to walk the extra distances needed to get water.

A far-reaching and broad response is clearly needed. The Government must lead the way, energising a cross-departmental approach, and policymakers, businesses and individuals everywhere should prioritise climate change. Everyone must play a part in being the solution – and only by doing so now can we begin to manage the impacts of today and minimise the threats of tomorrow.

Phil Bloomer

Campaigns and policy director, Oxfam

Cowley, Oxfordshire

As a female CEO in a male-dominated industry, I believe that imposing gender quotas on financial institutions is not the way to increase the number of female board members ("Crash makes it harder to attract women into bank boardrooms", 26 September). The long-term success of women in senior positions means female board members need to be seen to have earned their position through ability and hard work. Getting more women to board level is only half the battle. Once there, they must have the respect and authority to be effective, and quotas could serve to undermine this credibility. Firms should set their own targets. And, crucially, more women need to have the ambition, vision and self-belief from an early age to strive for board-level positions. There is a need for more female role models for girls to look up to and aspire to.

Marion King

Chief executive officer, VocaLink

Rickmansworth, Hertfordshire

Paul Vallely is right that the numbers don't really matter: minorities should be respected whatever their strength in numbers ("Minorities do not have a pecking order", 26 September).

However, the figures on homosexuality and bisexuality from the Office for National Statistics do look very unconvincing. An admission of having homosexual tendencies, even to a discreet stranger such as an ONS canvasser, will remain problematical for many who wrestle throughout their lives with the issue of disclosure. If ONS thinks that only 1.5 per cent of the UK adult population is gay, how does it square this with the gay website Gaydar's list of 1.5 million mainly male UK subscribers? In addition, there are the many British male homosexuals, never mind a majority of lesbians, who are not even Gaydar subscribers anyway.

Gavin Turner

Gunton, Norfolk

In the West, celibacy is merely a matter of custom and discipline, not of the substance of Catholicism (Letters, 26 September). Exceptions can be made, as for former Anglican priests who wish to continue their ministry. In many of the Eastern (ie, not "Roman") Catholic churches, which are nonetheless in full communion with the Holy See, married secular priests are common, though they must be married before their ordination to the diaconate.

Thomas Tallon

Bexleyheath, Kent

I have watched Harriet Harman's career with enthusiasm and admired the gusto with which she has fought national and personal battles ("So, farewell then, acting leader...", 26 September). In my view, she numbers among the great women of European politics. evoking the spirit of the great Alva Myrdal of Sweden, and is on track to becoming a towering figure of sense in a world of politics dominated by self-aggrandising men.

Sommarsang

posted online

Why do people think in extremes all the time? Beth Ditto ("Some do coke. Others do ciggies...", 26 September) claims that she is healthier at an "ample" size 26 than a skinny person who takes cocaine and smokes cigarettes to stay thin. That may be so, but between these two extremes is a world occupied by healthy people with a much better prospect of staying that way.

Francis Kirkham

Crediton, Devon

Your new ages of man and woman stop with the sixties ("Act your age!", 26 September). But many will live healthily into their seventies, eighties, nineties and maybe longer. Some will do paid work – soon most will have to – well into their seventies, take a degree, raise grandchildren, travel, engage in sports and art. It isn't all over by your sixties – you're just warming up.

Phyllida Morgan

Manchester

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Letters to the Editor, Independent on Sunday, 2 Derry Street, London W8 5HF; email: sundayletters@independent.co.uk (with address; no attachments, please); fax: 020 7005 2627; online: independent.co.uk/dayinapage/2010/October/3