G7 leaders agreed on Sunday to raise their contributions to meet an overdue spending pledge of $100 billion a year by rich countries to help poorer countries cut carbon emissions and cope with global warming, but only two nations offered firm promises of more cash.

Alongside plans billed as helping speed infrastructure funding in developing countries and a shift to renewable and sustainable technology, the world’s seven largest advanced economies again pledged to meet the climate finance target.

But climate groups said the promise made in the summit’s final communique lacked detail and the developed nations should be more ambitious in their financial commitments.

In the communique, the seven nations – the United States, Britain, Canada, France, Germany, Italy and Japan – reaffirmed their commitment to “jointly mobilise $100 billion per year from public and private sources, through to 2025”.

“Towards this end, we commit to each increase and improve our overall international public climate finance contributions for this period and call on other developed countries to join and enhance their contributions to this effort.”

After the summit concluded, Canada said it would double its climate finance pledge to $4.4 billion over the next five years and Germany would increase its by $7.26 billion a year by 2025 at the latest.

“G7 countries account for 20% of global carbon emissions, and we were clear this weekend that action has to start with us,” he said as the summit concluded.

The three day summit of the world’s seven richest leaders has come to an end:

“And while it’s fantastic that every one of the G7 countries has pledged to wipe out our contributions to climate change, we need to make sure we’re achieving that as fast as we can and helping developing countries at the same time.”

Some green groups were unimpressed with the climate pledges.

Catherine Pettengell, director at Climate Action Network, an umbrella group for advocacy organisations, said the G7 had failed to rise to the challenge of agreeing on concrete commitments on climate finance.