G7 climate ministers kick off two days of talks in northern Japan on Saturday, with campaigners warning the world's leading developed economies against backtracking on their fossil fuel commitments.
The group is under pressure to show unity at the meeting in Sapporo after a major UN climate report said the world would see 1.5 degrees Celsius of warming in about a decade. The report called for "rapid and far-reaching" efforts to keep temperature increases within relatively safe limits.
Overseas gas investments and steps to decarbonise grids at home are proving divisive as the energy crisis sparked by the Ukraine war squeezes the bloc, including this year's G7 president Japan.
Climate policy think tank E3G said "hard-won progress" at last year's G7 climate meeting in Germany was at stake on these issues and more, including increased support for poorer nations likely to suffer the brunt of a heating planet.
"Under the Japanese presidency these are either stalled or at risk of regressing," E3G warned in a statement.
"The lacklustre push from some G7 governments to prevent backsliding risks... undercutting any claim by G7 countries to providing global leadership on the essential task of confronting the climate emergency."
A draft G7 statement seen by AFP calls on nations to take action "in this critical decade", urging a peak in global greenhouse emissions by 2025 at the latest.
Experts say this language is aimed at China, the world's largest carbon emitter, which is targeting a peak of its carbon emissions by 2030.
The draft also stresses the "urgency" of slashing global emissions by 60 percent by 2035 from 2019 levels, as recommended last month by the UN's IPCC panel of climate experts.
Coal and gas promises
Other phrasing will be more contentious.
Ministers pledged at the last G7 climate meeting in Germany in May 2022 to largely end fossil fuel use in their electricity sectors by 2035.
They also agreed to stop new direct public support the same year for overseas fossil fuel projects that take no steps to offset carbon dioxide emissions.
But this was watered down a month later when G7 leaders said the "exceptional circumstances" of Russia's war in Ukraine made gas investments "appropriate as a temporary response".
The language now sought by Japan would solidify that exception, and trade minister Yasutoshi Nishimura said Friday a one-size-fits-all approach was inappropriate.
"The energy situation is different in each country, as we proceed on diverse paths towards carbon neutrality," he told reporters.
Coal may still prove the largest stumbling block, with Britain seeking a 2030 deadline to complete an "accelerated phase-out of domestic unabated coal power generation" to keep the 1.5C goal within reach.
Japan's preferred language would be a more general pledge to prioritise "concrete and timely steps" towards the phase-out.
Such wording may appeal to group members hit hard by the energy crunch, such as Germany and the United States, while others are pushing back.
A French government source said the country wants to "avoid or put a stop to any form of reversal on fossil fuel" commitments.
And Canada's environment and climate change minister Steven Guilbeault told AFP that "in terms of phasing out fossil fuel from the electricity sector... we would be, as Canada, very comfortable with having strong language on that".
Other potentially testy points include Japan's push for recognition of nuclear power and endorsement of its plan to start releasing treated water from its devastated Fukushima plant into the sea this year.
It also wants G7 recognition for its controversial strategy of burning hydrogen and ammonia alongside fossil fuels to reduce carbon emissions, which climate activists say only serves to extend the lifespan of polluting plants.
