Matt Ridley is the author of provocative books on evolution, genetics and society. His books have sold over a million copies, been translated into thirty languages, and have won several awards.

The other day at a talk I was asked, as I often am, whether I agree that only putting the state in control can clean up the environment. I wish I had then read this, from the blog at Cafe Hayek: a letter sent to the Los Angeles Times:

My latest Mind and Matter column in the Wall Street Journal is about the weakening of the magnetic field and, more generally, the question of how we scare ourselves by knowing more:

The earth's magnetic field is weakening at an accelerating rate. It is 15% weaker than it was at the time the north magnetic pole was "discovered"-and claimed for King William IV-by a British explorer in 1831. Should we be worried?

There is a lot of fuss about two new papers arguing, from mathematical models, that extreme downpours have become and will become more common in thenorthern hemisphereand specifically inBritainas a result of man-made climate change.

Let's ignore the fact that this looks awfully similar to the habit of blaming specific weather events on climate trends, something we `lukewarmers' (who think climate change is real but slow enough to adapt to through the foreseeable future) are reprimanded for doing when we point out that an especially cold winter or cool summer weakens the case for the alarming version of the theory. So now we can do that too, can we?

Let's ignore the fact that neither paper comes up with any actual evidence that greenhouse gases have caused more extreme downpours - other than circumstantial correlation. Their sole argument is that they cannot think of any other explanation for the increase in downpours. Or as the BBC puts it:

Ever since opening my own eyes by researching my book, I keep a watching brief for egregious examples of pessimistic bias in the media. Once your eyes adjust, the media's tendency to spot a cloud in every silver lining is very striking.

But just as striking is its ability to ignore anything that reaches optimistic conclusions.

As I have mentioned before, almost nobody has heard of the CO2-fertilisation effect. There is a new book by the Idsos that is well worth reading on this: there is a huge peer-reviewed literature on the benefits of CO2 enrichment and it is skilfully summarised here.

My latest Mind and Matter column from the Wall Street Journal is on Dunbar's number.

I was on BBC Radio 4's programme A Good Read (the link allows you to listen again) this week, where I recommended the book that was my favourite as a child, and probably still is: My Family and Other Animals by Gerald Durrell. The others chose A Game of Hide and Seek and Great Expectations.

Latest Mind and Matter column in the Wall Street Journal, on `unlearning':

For adults, one of the most important lessons to learn in life is the necessity of unlearning. We all think that we know certain things to be true beyond doubt, but these things often turn out to be false and, until we unlearn them, they get in the way of new understanding. Among the scientific certainties I have had to unlearn: that upbringing strongly shapes your personality; that nurture is the opposite of nature; that dietary fat causes obesity more than dietary carbohydrate; that carbon dioxide has been the main driver of climate change in the past.

I came across a rather good word for this kind of unlearning-"disenthrall"-in Mark Stevenson's book "An Optimist's Tour of the Future," published just this week. Mr. Stevenson borrows it from Abraham Lincoln, whose 1862 message to Congress speaks of disenthralling ourselves of "the dogmas of the quiet past" in order to "think anew."

I took part in a debate on whether we can feed the world on Al Jazeera television with Dvaid Frost. Video here.