Tony Juniper: There is no reason to despair

Signs of climate change do not confirm that the point of no return has been reached

James Lovelock's rather gloomy assessment, published in these pages on Monday, that we have passed the point of no return on climate change made for depressing reading over the breakfast table. While he is right to issue this wake-up call, I believe there is still room for optimism.

It is clear that climate change is happening. The Independent has been at the forefront of alerting the world to the signs, including the natural feedbacks that could massively accelerate the warming caused by people, such as the melting of Siberian permafrost and the potential release of massive quantities of greenhouse gases that would result. However these signs do not confirm, as Lovelock suggests, that the point of no return has been reached. We certainly face a crisis if nothing is done, but there is nothing to be gained by assuming the worst, especially when science says that there is still a window of opportunity.

The most recent modelling suggests the carbon dioxide equivalent of greenhouse gases in the atmosphere needs to peak at around 450 parts per million if we are to avoid the worst consequences of rapid climate change. It is still possible to avoid breaching this threshold, if the range of technologies and policies that are already available are deployed urgently. If politicians are willing to take the necessary action, the solutions could flourish.

In the UK, we could get on the right path by cutting carbon dioxide emissions by 3 per cent per year, every year. This is doable and affordable. We can hit this target through a combination of renewable energy sources, energy efficiency, cleaner use of fossil fuels and, crucially, the reduction of emissions from transport - including air travel.

Renewable energy remains a huge and largely untapped potential source of power. Not only through on-shore and off-shore wind turbines, but through a range of other technologies, including solar, tidal and wave power.

Using energy more efficiently must also be at the front line of efforts to reduce emissions. For example, research by Oxford University Environmental Change Institute has demonstrated how we can cut carbon dioxide emissions from our homes by 60 per cent through better building standards and improving the energy efficiency of existing houses, which are notoriously wasteful. Only 18 per cent of UK homes are fully insulated, and yet our homes use 30 per cent of the UK's energy.

We can and must use fossil fuels 40 per cent more efficiently, for example in combined heat and power plants. As a short term measure, we can even refit coal-fired power stations with higher efficiency boilers. Given all the things we can do now, relatively easily, it's no wonder that the big environmental groups are united in their opposition to nuclear power. This discredited and expensive source of electricity would take more than 15 years to make a contribution - a crucial 15 years when we need to be reducing emission, not waiting for nuclear to deliver on the false promises made half a century ago.

Transport emissions must be tackled too. Although the Department for Transport has been notorious for ignoring climate change and letting emission soar, its own research suggests hybrid cars and better public transport could cut emissions from surface transport by almost half.

The big challenge, of course, is to get these technologies and alternative energy systems taken up in practice. Not just here, but in all the high polluting countries across the world. Here, as elsewhere, it is political will that is lacking. But even in the US, there are signs of hope. Domestic pressure helped stop the Bush administration wrecking international climate talks in Montreal last December, while many individual states and cities within the US are taking their own action to cut emissions. Even the religious right is beginning to stir.

China, Brazil, India and other fast-developing countries pose very different challenges. There is growing interest in taking a clean development route in these countries. They need to get much more help from developed countries if they are to move swiftly to low carbon economies instead of automatically jumping to cheap fossil fuel-based energy sources. While in the UK, the Friends of the Earth campaign for a Climate Change Bill - which would commit the Government to making year on year reductions in carbon dioxide - has the support of 319 MPs.

Certainly Lovelock is correct to highlight how Gaia can exact her revenge, but it is not yet time to write the guide for global warming survivors. One thing is for sure: to give up the fight against climate change now would be utter madness. Time is short, but there is still time.

The writer is director of Friends of the Earth