On the anniversary of the 7/7 bombings in London, the world we live in gives us more than enough reasons to be afraid.

Mal Fletcher

In a world of 24/7 news coverage, much of it bad (because news by definition is about the abnormal), many people face the future with apprehension or even downright terror.

Terrorism is just one item on the menu of fear. Before 9/11, most threats to world peace came from nation-states. Now we're living in the age of the quasi-state, the suicide bomber, the small terror cell. Most of us will probably never see a terror attack firsthand, yet somehow we feel they're a threat to us all.

Another threat to our collective peace of mind is global warming. Some scientists predict that, over the next few decades, this will lead to severe storms, rising sea levels and radically different weather patterns.

Most people assume that the scientific community is unanimously agreed about global warming, but it isn't.

Some eminent climatologists have expressed doubts that it will happen at all. If it does, they are not sure how much of it will result from human activity, and how much is simply a natural phenomenon. And they haven't agreed on what can be done to prevent it. Many climatologists, perhaps the majority, do believe in global warming, but school's still out on what it will mean.

Next on the menu of fear might be the condition of life on planet Earth. To the best of our knowledge, there are a number of species that have suffered extinction in the past century alone. A number of others are threatened.

But as for future projections, we don't even know exactly how many species there are on our planet. Some say it's 3 million, others say 100 million. So how can we make predictions about extinction rates?

We are right to be concerned about these things; we can't afford to be complacent. But we shouldn't let fear overtake our pursuit of more information, or the proper use of the often limited data we already have.

Fear can be manipulated. Science and news can be politicized and sensationalised to serve interests other than those of pure research.

If knowledge is power, it is sometimes misused - usually in the name of public security.

Politicians sometimes need public fears to build a support base; governments need fear to control their citizens and raise money through new taxes. The news media need scary stories to build an audience. And special interest groups need threatening tales of impending disaster to justify their existence, to pay their bills and to enlist new volunteers.

In a social sense, there are probably some positive sides to our collective fears. A certain amount of fear makes us more alert in the face of trouble. New strains of flu virus, for example, push us to find new cures.

Fear can also help with building social cohesion: people tend to hang together when they feel threatened. After 9/11, the French President, Jacques Chirac famously declared: '[Today] we are all Americans.'

These benefits, though, are usually short-lived and some have a dangerous flip side. Fear of sickness can become a contributor to more sickness. Pulling together inside our social group can mean that we become suspicious of outsiders, to the point where the world becomes a place of 'us' versus 'them'. That's the root of every form of xenophobia and racial or religious hatred. Aristotle once said: 'No one loves the man whom he fears.'