Natalie Brook  is a Climate Change Campaigner for Oxfam.

Those of us calling for world leaders to take climate change seriously were heartened to hear that the Canadian government bowed to pressure from environmentalists, Nobel Peace Prize Laureates and more progressive countries early last week to include climate change on the G8 and G20 agendas .

Early indications that climate change was to be completely ignored by the summits were met with derision from campaigners around the world, and even ex Canadian PM Paul Martin called on leaders to “send out the proper signals”  so that the next meeting of climate negotiators in Mexico later this year has a chance to succeed.

This is good news; climate change must remain at the top of the global agenda. The G8 and G20 meetings are the first major opportunity world leaders have to discuss climate change since the disappointment of Copenhagen last year.

The test of the summits will, however, not only be on whether G8 and G20 leaders utter the words ‘climate change’ but on what they agree to do about it. The success of the meetings should be judged on the ambition of leaders’ actions: will they push forward on commitments made at Copenhagen to provide the cash needed to start tackling climate change? Will they commit to ensuring that this money isn’t diverted from other aid priorities?

Oxfam is calling on the G8 to:

• Provide the promised $30 billion climate finance by 2012
• Make progress towards agreeing a fair and sufficient Climate Fund for long-term financing
• Ensure they don’t plunder aid budgets to pay for helping poor countries cope with climate change

It might sound like climate financing will require a lot of money, but it’s easier than you might think to find. There are new ways of raising the money, like a financial transaction tax, which would provide what’s required and leave change to spare.

The G8 and G20 will be judged by the actions they agree to take. Words alone won’t meet the challenge.