Leaders of the world's biggest economies made a compromise commitment on Sunday to reach carbon neutrality "by or around mid-century" as they wrapped up a G20 summit paving the way for the crucial COP26 conference now getting under way in Scotland. In a final communiqué, the Group of 20 leaders also agreed to end public financing for coal-fired power generation abroad, but set no target for phasing out coal domestically — a clear nod to top carbon polluters China and India. Negotiators for the Group of 20 worked through the night and talks continued Sunday morning trying to reach consensus for a final statement. According to the communiqué, the G-20 reaffirmed past commitments by rich countries to mobilize $100 billion (€86.50) annually to help poorer countries cope with climate change, and committed to scaling up financing for helping them adapt. A key sticking point remained the deadline for nations to reach carbon neutrality or "net-zero" emissions, meaning a balance between greenhouse gases added to and removed from the atmosphere. Going into the summit, however, Italy had all-but conceded it would only be able to secure commitments to reach net-zero emissions "by mid-century," rather than a specific year. The final communiqué appeared even weaker, "acknowledging the key relevance of achieving global net-zero greenhouse gas emissions or carbon neutrality by or around mid-century"." British Prime Minister Boris Johnson, who had wanted every G20 member to commit to net-zero by 2050, said after the summit that the pledges were not enough, saying some countries were "not doing their fair share of the work". The UK's Prince Charles, a long-time environmentalist, addressed the G20 on Sunday morning before the final communiqué was known. Warning that "it is quite literally the last-chance saloon," Charles told the Group of 20 leaders that public-private partnerships were the only way to achieve the trillions of dollars in annual investment needed to transition to clean, sustainable energy sources that will mitigate the warming of global temperatures. "It is impossible not to hear the despairing voices of young people who see you as the stewards of the planet, holding the viability of their future in your hands," Charles told the presidents and prime ministers gathered in Rome. Earlier on Sunday, G20 leaders gathered at Rome's Trevi Fountain before getting back to work hammering out a final statement on climate change. Each tossed a coin into the water in line with tradition, although US President Joe Biden was a notable absentee. The Group of 20 countries represent more than three-quarters of the world's greenhouse gas emissions. The commitments they agree on are seen as key in setting an example for COP26. It's feared that weak pledges may lead to momentum being lost. "We must accelerate the phasing-out of coal and invest more in renewable energy," Italian Premier Mario Draghi said going into the final working session. "We also need to make sure that we use available resources wisely, which means that we should become able to adapt our technologies and also our lifestyles to this new world." Western countries have moved away from financing coal projects in developing countries, and major Asian economies are now doing the same: Chinese President Xi Jinping announced at the UN General Assembly last month that Beijing would stop funding such projects, and Japan and South Korea made similar commitments earlier in the year. China has not set an end date for building domestic coal plants at home, however. Coal is still China's main source of power generation, and both China and India have resisted attempts for a G20 declaration on phasing out domestic coal consumption. G20 leaders also discussed the COVID-19 pandemic and the uneven distribution of vaccines in the world. On Saturday they endorsed a global minimum tax on corporations, a linchpin of new international tax rules aimed at blunting fiscal paradises amid skyrocketing profits of some multinationals. And after a meeting on the sidelines about Iran's nuclear program, Biden, Johnson, Germany's Angela Merkel and France's Emmanuel Macron made a joint statement expressing their "determination to ensure that Iran can never develop or acquire a nuclear weapon." They also voiced concern that Tehran "has accelerated the pace of provocative nuclear steps" after halting negotiations on a return to the nuclear agreement, formally known as the Joint Comprehensive Plan of Action. — Euronews