The language of international negotiations often needs decoding. When the politicians pronounced a “successful deal” on climate change at the G8 summit yesterday, they were naturally putting a positive gloss on an agreement which is still a long way from an ironclad commitment to reduce greenhouse gases. Yet to brand it rather scornfully as a “compromise”, as others have done, is to underplay the significant progress that has been made. Of course the deal is a compromise. That is in the nature of such talks. What matters is that America has clearly come in from the cold.

It was Tony Blair who first put climate change on the G8 agenda two years ago. What he wanted most from this summit was an American commitment to participate in the UN process for developing the new international framework which must replace the Kyoto Protocol before it expires in 2012. This is what he and Angela Merkel, the German Chancellor, have achieved. While America remained the only G8 nation outside the Kyoto Protocol, it was unlikely that India and China could ever be persuaded to participate in any meaningful way.

So the White House’s shift is highly significant, although it is timid when compared with the bold targets already set unilaterally by US states such as New York and California, and also when put alongside the calls for action by many US businesses. The change in the American position this week enables the parties to get on with developing the details of a post2012 framework and is an incentive for companies and individuals to examine their own carbon footprints.

While nothing can come too quickly for those who fear that time is running out to combat climate change, it is worth noting that the pace of recent change has been remarkable. At the Gleneagles summit two years ago, President Bush was still reluctant to address climate change. Even the nations of the European Union that had signed the Kyoto Protocol were making almost no headway in meeting those modest targets.

It’s Grrrrr8 (honest)

As the G8 summit begins in Germany, Hugo Rifkind explains everything you need to know – and lots of stuff you don’t

Multimedia

• Audio: Behind the scenes at the G8

• Pictures: G8 summit

BACKGROUND

• Quotes: what Putin told The Times

• Blair reinvented the Middle Ages

• The West is starting this Cold War

• Save the planet: give to China

Yesterday, President Bush agreed in principle to a long-term goal to reduce emissions. And Nicholas Sarkozy, the new French President, made a forceful case for action on the target of reducing emissions by 50 per cent below 1990 levels by 2050, which Mrs Merkel has been pushing so staunchly. Clearly, more progress needs to be made in United Nations negotiations. But after this week’s show is over and everyone has gone home, each country will have work to do, as will Europe as a whole. One of the most significant is its carbon trading scheme, under which companies trade permits to pollute.

The European Commission has tightened the scheme from next year so that Europe’s biggest polluters should soon face a carbon price that is high enough to encourage far more profound changes than they have made so far. Companies in other countries, particularly Australia and the US, are interested in following suit.

There is a critical mass of world leaders who at least say that they take climate change very seriously. The Prime Minister deserves credit for this and for forming a formidable alliance with Mrs Merkel.

There is far too much emotion inspiring the debate about climate change – the world is warm enough without heat and light characterising the conversation. The Baltic pact is a victory for sound science and for the planet.