Don't the leaked emails from the University of East Anglia show that dissent on climate change is crushed whenever it appears? STACEY PURNELL, BRIGHTON
Science should always be sceptical. Questioning theories by subjecting them to rigorous testing is the foundation of scientific method – it's how our body of knowledge was built. The revelations at the University of East Anglia are deeply concerning, but our knowledge of climate change doesn't hang on this set of emails, but on the work of thousands of different scientists, pursuing many separate lines of inquiry over many years.
Good climate change policy is all about taking those actions that protect against unacceptable risks, while delivering additional benefits – such as energy security and economic opportunity – whatever happens to the climate.
The main consequence of environmentalism entering the mainstream has been the resurrection of imperialism: people like you telling the poor world not to develop. Why? MARTIN HOFSTADER, BERLIN
Actually, I think environmentalism and climate change agreements have the potential to help the world's poorest immeasurably. Even assuming the most optimistic development pathways, the world's poorest people make, and will make, very little contribution to the problem. However, they are disproportionately vulnerable to the consequences and have every interest in a meaningful global deal. The global deal that I would like to see would protect the developing world from climate change, but not exclude them from development.
Indeed, for the emerging industrial giants like China, a global deal may be an opportunity to develop, rather than a hindrance to development. The transition away from fossil fuels would provide huge opportunities for manufacturing exports – which is one reason why the Chinese are playing an increasingly constructive role in international negotiations.
How will pricing poor people out of the sky help win public support for action against climate change? CASSANDRA MORGAN, CARDIFF
It wouldn't, which is why it isn't our policy. We believe that it's important to offer an efficient and clean high-speed rail alternative, so as to reduce the need to travel by air within the UK and much of Europe. This rail network would make a third runway at Heathrow unnecessary, reducing pollution and congestion.
If Kyoto wasn't a success, why will Copenhagen be? GREGORY SAMUEL, SHEPTON MALLET
Because the problem is more pressing, the technological solutions are more advanced, the Chinese and Americans are more willing and fossil fuels are more expensive.
If Liz Truss should have told her local association and Cameron about her affair, should Zac Goldsmith have done the same about his non-dom status? NEIL UPTON-FARR, LONDON
The relevant body is his electorate, and he has told them that he is now, and will continue to be, a full UK taxpayer.
Are you more embarrassed by Zac Goldsmith's tax arrangements than those of Lord Ashcroft? OSCAR WRIGHT, Taunton
See above for my answer on Zac Goldsmith. I have no knowledge of Lord Ashcroft's tax bill, so it's hard to see how I can fairly comment on it.
Was your inheritance-tax policy dreamt up on the playing fields of Eton? Is it going to land you in an Eton mess? (Or will class warfare damage Labour?) JANINE PICKERING, DERBY
I believe our leaders should try always to unite, rather than divide – to strengthen the country rather than introduce tensions. So it's a shame that creating "dividing lines" and "class war" seems to be Labour's intended strategy. I don't think it's what people hope for from their Government and it's likely to damage Labour's standing. Inheritance tax sends a message about the value of saving – which we need more of. We believe that only millionaires should pay inheritance tax.
Isn't it funny that Zac Goldsmith – expelled from Eton but that's OK because daddy left him hundreds of millions – is a non-dom? You couldn't make it up! ROBERT MORGANm LONDON
My answers to Neil and Janine's questions above cover both points.
How do you reconcile your policy on the budget deficit with a tax break for millionaires? MARTINA SIMMm GLASGOW
It precisely isn't a tax break for millionaires – they will continue to pay inheritance tax under our plans. It doesn't add a penny to the deficit – it's a tax switch rather than a tax cut: wealthy non-doms will pay a new levy, the proceeds of which will be used to lift people with smaller estates out of inheritance tax. Bear in mind it's not just the super-rich who pay inheritance tax – anyone with a house worth more than £325,000 is at risk of paying it.
It is the Conservatives who have consistently been straight with people about the scale of the debt crisis and the need to take action to tackle the deficit. We have set out some of the tough choices we would make, such as a one-year public sector pay freeze for those earning over £18,000, and bringing forward the planned increase in the state pension age.
The Lib Dems' policy of taking low-earners out of income tax will cost money upfront, but is progressive, creates incentives to work, and saves money in the long term by cutting benefits. Why is it not Tory policy? If it were, I'd vote for you. MARY HODGSON, ANDOVER
I have a lot of sympathy for reducing taxes on the low-earners. But according to figures from the Treasury, there's a £5.5bn gap in the Lib Dems' sums. At a time when we have the largest budget deficit in the developed world, it's irresponsible to produce proposals that risk misleading the public. We're in favour of lower taxes, and our priority will be to keep people working by trying to reverse the rise in National Insurance – a tax on jobs – that Labour have announced.
Do you believe in God? If so, why is He allowing climate change to happen? PREMJEET SAHAL, LEICESTER
I do. And I believe he gave us the free will and the ability to overcome this and many other challenges.
I s George Osborne embarrassed that Ken Clarke and Philip Hammond were appointed to give your party economic credibility? AMANDA WYNNE-THOMSON, READING
Well, we could always follow Labour's example and leave economic policy in the grip of just one man. But we're guessing the country's had enough of that.
Why are there so many Gregs in the Tory ranks (Hands, Barker, Clark, etc)? GREGORY ARMSTRONG, NORWICH
There were 16 Popes called Gregory, so I don't think we've exceeded our quota quite yet. But we'll keep a watch on the situation. Still room for another one if you want to come on board, Gregory...
Are you a red Tory, a green Tory, or a blue Tory? MATTHEW SCOTT London
The purest light comes from a balanced spectrum.
Why hasn't your house got a windmill on it, like Cameron's? SARAH GRIMWOOD, Brighton
Because it wouldn't recoup the cost. But there are things that can be done that save CO2 and save money. We have some of the worst homes – in terms of energy efficiency – in Europe. Improving them cuts fuel bills, but needs upfront capital that many people simply don't have.
That's why our Green Deal would give every household in the country an immediate entitlement to up to £6,500 of energy-efficiency improvements, to be paid for out of some of the savings people make on their bills over time. This shouldn't be party political – I genuinely don't understand why the Government refuses to include energy efficiency in the Energy Bill that comes before Parliament today. If they did, I would help get it into law as soon as possible. Perhaps it's an application of that "dividing lines" strategy – if we're in favour of something, they must be against it. That's the wrong politics for the environment.