G7 nations, representing the world’s most advanced economies, on Tuesday announced they would end the use of “unabated” coal by 2035, but left the door open for some members to go beyond the deadline in particular contexts.

Furthermore, while the agreement was laudable having roped in Japan, the erstwhile sole defender of coal in the G7, it did not include any mention of natural gas, the largest source of carbon-dioxide increase globally over the last decade. Rather, many G7 members are now investing in new domestic gas facilities.

The G7 typically leads on global climate policy with its decisions often trickling down or influencing the wider G20, which is dominated by emerging economies, according to CNN.

In a communiqué published after talks between energy, climate and environment ministers in Turin, Italy, the group announced it had committed to “phase out existing unabated coal power generation in our energy systems during the first half of 2030s,” in a climate policy breakthrough that G7 negotiators had previously failed to achieve in several years of talks.

But by referring to “unabated” coal, the agreement leaves room for countries to use the fossil fuel past 2035 if their carbon pollution is captured or offset before entering the atmosphere –  a phenomenon known as net-zero effect.

The agreement also includes a caveat that countries could choose “a timeline consistent with keeping a limit of 1.5°C temperature rise within reach, in line with countries’ net-zero pathways.”

That caveat appears to allow those countries to keep using coal past 2035, as long as their overall national emissions won’t contribute to global warming of more than 1.5 degrees Celsius above pre-industrial levels. Science shows that some of the planet’s ecosystems will reach tipping points or struggle to adapt beyond that point.

Several members of the G7, which represents the biggest economies in the developed world, have already come close to ending the use of coal. Coal makes up less than 6% of the electricity mix in the UK, Italy and Canada, and almost nothing in France. But it still comprises 32% of Japan’s electricity mix, 27% of Germany’s and 16% of the US’, according to the think tank Ember.

“Many of these countries have already publicly committed to phase out dates ahead of 2030, and only have a small amount of coal capacity anyway,” Jane Ellis, head of climate policy at Climate Analytics, told CNN.

The agreement comes just days after the US Environmental Protection Agency announced new rules that will require coal-fired power plants to either capture nearly all of their climate pollution or shut down by 2039.

When questioned by journalists on the caveats in the G7’s agreement, Italian Environment and Energy Security Minister Gilberto Pichetto Fratin defended the agreement, saying the language shows “G7 countries undertake to phase out the use of coal, without jeopardizing the various countries’ economic and social equilibrium.”

The language is weaker than what UK minister Andrew Bowie told a reporter on Monday: that the group had agreed to end coal by 2035, making no reference to unabated coal or wiggle room in the timeline.

Despite the caveats, several climate policy experts welcomed the announcement, describing it as a breakthrough after years of roadblocks on the issue.