Given a five-year electoral cycle and a 30-year lead time for CO2 emissions to affect climate, is there any way to make politicians listen in time?
Nigel Weiss, via email
I have been impressed by the way in which the world communities have come together to recognise climate change as a problem. The recent Bali summit represented global political agreement that there is a problem and a consensus that action must be taken to reduce emissions. In my view, there has been considerable progress over the last few years, but there is a very long way still to go.
Is nuclear power safe? Can we make the reductions in carbon emissions we need to without it?
Georgina Bratt, Southampton
Yes, modern nuclear power is a dependable and proven technology, currently supplying a fifth of our electricity supplies. We need clean, secure, and affordable energy supplies if we are to continue to function as a modern society. It would be possible to achieve the UK's emission reduction targets without nuclear power, but it would cost us a lot more money.
Do you agree with your predecessorSir David King that climate change is a bigger threat than terrorism? And where does food security rank?
Simon Burley, Glasgow
Climate change has the potential to seriously disrupt the world community. To address it, actions are needed now and in the future. Terrorism is an immediate and difficult problem that also requires action now and in the future. The rapid increase in food prices means that food security is an problem for the world's poor, while population growth, globalisation and other factors will make it a problem for the future. All these challenges need to be addressed, but it is important to recognise that some are linked. If climate change is not addressed, then growing food will be made more difficult. Similarly addressing food security should not be at the expense of attempts to mitigate climate change.
Is Prince Charles right about GM crops?
Mary Meade, Godalming
Not entirely! Although, it is important that we have an informed debate on the issue. GM offers one of many technologies which one day could play an important role in ensuring food security for a growing population. But no one technology offers the solution and whichever technology is used, it must be within an appropriate regulatory framework that safeguards the environment and human health. We have strict controls on GM crops that do that.
You chair an advisory panel on biometrics that warned old people might not be able to give good enough fingerprints for ID cards. Do you think the cards are feasible or cost-effective?
Leonard Baird, Chepstow
Biometric technologies are available today and are being used worldwide. They are also developing rapidly, so an identity card scheme is technically feasible. Even though the fingerprints of some older people are of a lower quality, the collection of fingerprints is just one part of the enrolment process. A decision to implement ID cards depends not only on the technology, but many other factors.
What impact does public ignorance have on policy? How can we make people more scientifically literate?
Ruth De Freitas, Antrim
Building scientific literacy is a key part of the Government's Science & Society Consultation. The Science and Engineering Ambassadors programme which has more than 20,000 scientists and engineers visiting schools across the UK and events like the National Science and Engineering Week do much to develop enthusiasm for the subject and help the wider public engage with science.
Is serious drug use a health problem or a crime? What is your advice to the Government on the war on drugs?
Jay Athumani, London
Drug misuse can lead to serious health problems and is a major cause of crime. The "war on drugs" cannot be won by science alone, however science can certainly help us understand the reasons for addiction and to develop policies, and medicines that will help prevent and treat addictions.
Do you see a tension between being a government adviser and a scientist?
Russell Thorpe, Taunton
As I was a scientist long before I became a government adviser, I see no particular problem. My job is to ensure that the best possible scientific advice is presented to the Government and that, where there are uncertainties, they are clearly explained.
Considering the popularity of acupuncture and homeopathy, are we more gullible than we used to be?
Sarah Cooper, Coventry
No, however we need evidence to be able to make informed comparisons, beyond the placebo effect, on the efficacy of complementary and alternative medicines and other treatments. The Department of Health is working on this. I know no scientific evidence supporting homeopathy.
Are you worried about the world's fish stocks running out in the next 50 years? What can we do to avoid that happening?
Paul Murray, Nuneaton
I do not believe that the world's fish stocks are going to be depleted, and certainly not to extinction, in the next 50 years. The key problem is that there are too many fishers and fishing vessels pursuing too few fish. Scientists and managers know what is needed to manage fisheries sustainably, but there are barriers due to social issues and political constraints.
Do you believe in God?
Liz Wellsley, Lancaster
Such belief is a private matter. However, I do not believe that scientific evidence is going to provide any information about the existence or not of a God. Some belief systems do contradict scientific evidence and where this occurs my support is for the scientific evidence. What I do believe is that there is a moral code and that it is possible to distinguish between good and bad actions. This is not dependant on a belief in a God.
What will be the next great scientific advance?
Kathy Beckman, Kidderminster
I wish I knew. The real trick in Government is having a process in place that looks to the future so that we do not miss opportunities and stand a better chance of finding enduring solutions. Foresight and its Horizon Scanning Centre in the Government Office for Science do just that.
Is there really a chance that the new Cern particle collider could create a black hole and swallow up the planet? And what is the point of it, exactly?
Thomas Walker, Didcot
No. Scientific evidence indicates that the Large Hadron Collider will be safe. Even if black holes were produced they would be microscopic and disappear before they could expand into astronomically-sized planet gobblers. Cern will re-create the conditions just after the Big Bang and will hopefully enable us to find the answers to fundamental questions about the universe, such as the origin of mass and what dark matter and energy is. New cancer therapies, advances in electronics, new manufacturing processes and materials and even the World Wide Web are just some of the many technologies that have been developed at Cern.
Will humans ever settle on another planet?
Jay Haddad, London
I don't know, for it is impossible to predict the advance of science and technology. However, the USA is planning to begin building a permanently crewed outpost at the Moon (not a planet!) starting in 2020. Exploration of the Moon could be preparation for a longer term human mission to Mars.
Settling on a New Earth outside the Solar System will have to wait until we can develop new propulsion techniques to cross the enormous distances between stars.
Should I drink tap or mineral water?
Alice Goudreault, Chester
Tap water is safe to drink in the UK and doesn't come in plastic bottles, but it comes down to your own personal preference. I drink tap water.
Can you tell me an experiment I could try with my 10-year-old to get him interested in science?
Gavin Hopson, Maidstone
A simple chemistry experiment which shows how an acid mixed with an alkali produces salt and water is possible with kitchen ingredients. Mix baking soda (an alkali) with vinegar (an acid) and, following a lot of fizzing, salt is produced. It is theoretically "edible" but I wouldn't recommend tasting it!
More generally a visit to the Science Museum is well worth it.