Speaking at the annual informal Petersberg Climate Dialogue in Berlin, German Foreign Minister Annalena Baerbock said leaders were working hard to stay "on track for a successful COP27" in Egypt.

"Global circumstances are not making this an easy task," she said, blaming Russia's invasion of Ukraine for exacerbating "a global energy and food crisis that is pushing millions into poverty, hunger and starvation".

The international community has agreed that climate change poses an existential threat to human systems and the natural world.

But action to cut carbon pollution and prepare for the accelerating impacts is lagging, as is support for vulnerable countries confronting the ravages of a changing climate.

Maintaining international momentum has been made even harder with Russia's invasion of Ukraine and spiralling food, energy and economic crises.

At a meeting in Bonn in June to lay the groundwork for the Egyptian conference, Egyptian Ambassador Mohamed Nasr said climate change was being "pushed back" due to these new challenges.

- Sticking points -

The main sticking points are around issues of finance, such as money for adaptation and the idea of a specific funding stream for controversial "loss and damage".

Baerbock on Monday said it was "important to us to give adaptation and loss and damage... the attention they deserve".

Egyptian Foreign Minister Sameh Shoukry added it was key that "the current state of affairs is not taken as a pretext to backtrack or renege on previous commitments, especially those related to supporting developing countries".

Speaking at the same forum, Chancellor Olaf Scholz said Russia's war "has only strengthened our resolve" to achieve climate neutrality by 2045.

However, as it looks to wean itself off Russian energy, Europe's biggest economy has decided to reactivate old coal-fired plants and is also eyeing new gas projects.

"No one can be satisfied with the fact that the share of coal-fired power generation in our country is rising again," Scholz said, promising it was "an emergency measure for a limited period of time".

Egyptian leader Abdel Fattah al-Sisi also urged rich nations to keep up the fight against climate change.

"In this critical time that the world is experiencing it is important that we all make an effort and... work together to confront the challenges," he said.

Former German chancellor Angela Merkel initiated the Petersberg Climate Dialogue after stalled negotiations at the 2009 United Nations Climate Change Conference in Copenhagen (COP15).