Gordon Brown warns of a "climate catastrophe" if we don't do more to tackle climate change. One of the critical problems is changing the public's behaviour to be more 'green'. Warnings of droughts, floods and soaring temperatures are very dramatic so why aren't we doing more?

From a psychological perspective five key factors make it hard to turn us 'green'. The first reason is what psychologists call salience. This means people tend to overestimate the likelihood of things that are easy to imagine and underestimate the importance of something that might happen in the future. Heat waves and scorching temperatures are probably difficult for many UK citizens to imagine given our recent experiences of cold, wet summers. These factors lead us to underestimate the effects of climate change.

Secondly, as psychologists we know that when confronted by too many options people feel confused and so default to doing nothing. We therefore need clear guidance on the impact of the many 'environmentally friendly' options to help us choose what is most suitable for us.

Thirdly, we need leaders to act as better role models because we look to people in authority to see how to act. Whilst leaders tell us to cycle, take public transport and car share we see them being driven to work usually in gas guzzling cars. This is hardly conducive to changing our driving habits.

Fourthly, even small habits are hard to change so we need suitable alternatives. It is a struggle to get us to drive less when public transport is unreliable, inconvenient and too expensive.

Finally, people tend to be loss averse which means we need to position the benefits of change in terms of avoiding a loss rather than making a gain. For example, telling someone that if they do not use energy conservation methods they will lose £350 a year is more effective than telling them that if they do use energy conservation methods, they will save £350 a year.

If leaders want to make us more 'green' they need understand what makes us more likely to change and invest in ensuring that we do. We need examples that are easy to relate to, clarity about the impact of our options, role modelling of desired behaviours, suitable alternatives and to know what we stand to lose rather than what we will gain.