David King: At last, I'm hopeful about climate change

For those of us seeking to tackle the threat of climate change, 2006 was an encouraging year. At the start of the year, the conversation - when it took place at all - was about whether climate change was really happening. That discussion is now over.

This public shift has been mirrored in the political and industrial arenas. Australia was once vehemently opposed to the Kyoto Protocol, and indeed to any government-based incentives to attempt to cap carbon emissions. But in November, the Australian Prime Minister, John Howard, announced that fiscal measures were now necessary to deal with global warming. California, under Republican Governor Arnold Schwarzenegger, has even promised to reduce its emissions by a full 80 per cent by the year 2050, which is the highest formal commitment made anywhere in the world.

Companies too have begun to recognise that climate change is not just a threat but an opportunity. Earlier this year retail giant Wal-Mart announced it had reduced energy consumption (and therefore energy costs) by 42 per cent. With their internal emissions trading scheme, BP saved $650m (about £340m) over three years, and others are following suit.

And of course, in November there was the Stern report, which finally put paid to the tired arguments that dealing with climate change is too costly to the economy. As Nick Stern demonstrated clearly and effectively, tackling climate change need not cost the Earth. It is only if we make no effort to curb emissions that the world economy will be crippled. All political, economic and social arguments now point to the same conclusion. We need to deal with carbon emissions, and we need to start now.

Let's talk numbers. Carbon dioxide levels are now at 383 parts per million (ppm). Adding in all the other greenhouse gases to calculate a so-called "carbon equivalent" (CO2e ) tells us that we are already at something like 430 ppm. Most scientists believe that passing 400ppm CO2e has taken us into dangerous territory, and that anything approaching 550ppm would bring the sort of drastic changes that nobody wants to contemplate. Then, it would no longer be a case of strengthening coastal defences and shifting crops around. In the long term, it is unlikely that even the strongest economies in the world would be able to cope. This is not scaremongering, but real science.

It is essential that we reach a global agreement for an emissions target, and swiftly. November's Nairobi UN climate change meeting was disappointing in this regard. However, perhaps it is just too difficult to achieve a deal among 189 countries at a stroke. Rather I think we should also look to the promising actions brokered in September's "Gleneagles dialogue" meeting in Mexico. This was born directly out of the Gleneagles meeting under the UK's G8 presidency in 2005, to which Tony Blair invited not just the G8 and EU representatives but also the world's major rapidly developing countries: India, China, Brazil, South Africa and Mexico.

I believe this new grouping of "G8 + EU + 5" could be the key to finding an equitable strategy by which we in the developed world can substantially reduce our emissions, while bringing these rapidly developing countries on to the path of reducing theirs. And I am very encouraged that Germany, who will hold the G8 presidency from today, has already offered to host the next Gleneagles dialogue meeting.

The science has been clear for some time, as emphasised at the meeting in Mexico, that as well as reducing emissions, we will also need to adapt to the global warming impacts that are already in the pipeline. Some of this adaptation is now underway. Following the Foresight Programme I instigated in 2001, the UK increased flood defence spending from £200m in 1998 to almost half a billion this year, helping to make the UK a world leader in adaptation planning.

Last year I signed an agreement with the Chinese government to strengthen the defences of the vulnerable Shanghai region. However, these adaptations are just the beginning. Nation by nation and across neighbouring borders we will have to find ways to respond to rising seas, higher temperatures, changes in rainfall patterns and storminess.

I believe the best overall strategy for adaptation will be to look at the likely impacts of climate change over the next 30 years, and then set up projects to manage the resulting risks to the populations. We in the UK can offer one of the world's most sophisticated facilities to make the necessary predictions. Since 2003, in collaboration with the Japanese Earth Simulator Computer, UK researchers have been using the Hadley Centre model to determine near-term climate change impacts country-by-country and region by region at an unprecedented detailed scale. This in turn can be used to ensure that we can be prepared for the damages to come.

Looking into this year I see three key challenges: Firstly, we in the UK must continue to demonstrate that significant emissions reductions and prosperity can go hand in hand. The UK has already shown real leadership in this respect, cutting emissions by 15 per cent between 1990 and 2002, while the UK economy grew by 36 per cent. By 2010, with a projected economic growth since 1990 of around 50 per cent, our total greenhouse gas emissions will have been reduced by about 24 per cent.

Secondly, we must redouble our efforts to develop the technologies we need to achieve a low carbon economy. By autumn this year, I hope to see the new Energy Technologies Institute fully operational, and beginning its work to accelerate key low carbon technologies towards deployment in the market. The range of private sector companies joining up with government in this billion pound investment is impressive. The funding will be focused on energy efficiency, low carbon transport, renewables, cleaner fossil fuels and methods to capture and store carbon dioxide from power plants before it can escape into the atmosphere.

Thirdly, and arguably the biggest challenge, is on the international front: We need to ensure that real progress is made towards a long-term framework for action on the scale and with the urgency required. Ultimately, only heads of states, working together, can provide the global leadership needed to steer the world on a path towards a sustainable and prosperous future.

Taken together, events last year have brought the prospect of tackling global warming a giant leap forward. I am now looking forward to 2007 with more hope than I had imagined at the beginning of last year. We need to remember: action is affordable - inaction is not.

Professor Sir David King is the Government's Chief Scientific Adviser