The Bonn Climate Change Conference is seen as a mid-way check for how international climate talks will take shape in December.
United Nations climate talks kicked off in Germany on Monday (5 June) without an agreed final agenda for technical discussions, a senior negotiator said.
The lack of a plan is clouding optimism that the 10-day meeting will result in a clear programme for the COP28 conference in Dubai.
The Bonn Climate Change Conference, designed to prepare decisions for adoption at COP28 in the United Arab Emirates, is seen as a mid-way check for how international climate talks will take shape in December.
Despite months of discussions since the previous COP27 in Egypt, there was no agreement on adopting the agendas proposed by the COP permanent subsidiary bodies for the Bonn conference, Nabeel Munir, chair of the UN Subsidiary Body for Implementation (SBI), said at the opening of the talks.
"What we experienced today ... with the non-adoption of the agenda, it's not desirable, but it's not uncommon in a party-driven process," Simon Stiell, executive secretary of the UN Framework Convention on Climate Change (UNFCCC), told a news conference on Monday.
COP28 could be the most significant climate conference since Paris
Stiell said the December conference could be the most significant one on climate change since Paris as it provides the world with an opportunity to get on track to meet the 2015 Paris climate protection commitments.
Making as much progress as possible in Bonn in the coming 10 days is important. The conference, with 200 countries' representatives, sets the technical groundwork for the political decisions required in Dubai later this year, Stiell added.
Tom Evans, a policy adviser at independent climate think tank E3G, said the main issue was whether to have an agenda item on climate change mitigation in the Bonn conference. It has been proposed by the European Union which is posing the question of phasing out fossil fuels.
"It's a bit of a warm-up to some of the tension around this question that we could see at COP 28," he added.
Will COP28 see an agreement to phase down fossil fuels?
At last year's climate summit in Egypt, over 80 countries including the EU and small island nations agreed to include language in the final outcome calling for a phase down of all fossil fuels.
Countries including Saudi Arabia and China urged Egypt not to include that language in the final text.
Asked whether Stiell would push COP28 president designate Sultan al-Jaber to put fossil fuel phaseout on the Dubai conference agenda, he said, "I'm not there to tell him anything."
But he said the secretary's position was clear that halving emissions by 2030 and reaching net zero by 2050 required a deep cut and phasing out or down of all fossil fuel, Stiell added.
The Bonn conference will witness talks on climate change policy issues including the so-called global stocktake at COP28 - a review of countries' collective progress every five years. It is the first such procedure since the Paris Agreement in 2015.