One of the computer models for a four degree temperature rise would give rise to a 10 degree temperature rise in Africa. And bear in mind also that in the depth of an ice age the mean temperature drop compared to the present was five degrees.

To ensure continuing prosperity in the global economy, nothing is more important than the development and application of knowledge and skills.

To most people in the UK, indeed throughout Western Europe, space exploration is primarily perceived as 'what NASA does'. This perception is - in many respects - a valid one. Superpower rivalry during the Cold War ramped up US and Soviet space efforts to a scale that Western Europe had no motive to match.

There may be organic life out there, or maybe machines created by long-dead civilizations, but any signals, even if they are difficult to decode, would tell us that the concepts of logic and physics are not limited to the hardware in human skulls, and will transform our view of the universe.

Scientists surely have a special responsibility. It is their ideas that form the basis of new technology. They should not be indifferent to the fruits of their ideas. They should forgo experiments that are risky or unethical.

I hope that by 2050 the entire solar system will have been explored and mapped by flotillas of tiny robotic craft.

I'm not a specialist in the science but I have followed it fairly closely and it seems to me that there is among the experts a clear consensus that potential climate change is something to worry about.