The 28 leaders will discuss the appointment of the EU’s top jobs, including the European Commission and the Council, for the next five years.
The main political groups in Parliament have not yet come forward, as expected, with a lead political party candidate for the Commission presidency.
As each of the four main groups have proposed their own candidate this would represent a compromise candidate.
An announcement was expected on Monday but, with the summit starting on Thursday, the four biggest groups, the EPP, Socialists, Liberals and Greens, had still been unable to settle on one candidate to propose to the summit.
A spokesman for the Socialist group in Parliament told this website, “The negotiations are ongoing and thus for now no news as such.”
A spokesman for the newly-renamed Renew Europe - formerly Alde - said, “Our candidate is Margrethe Vestager.”
Parliament is still wholeheartedly defending the so-called ‘Spitzenkandidat’ process, which effectively means that the candidate from the winner of the European elections should be taken into consideration for the presidency of the Commission, the EU’s top post.
Senior MEPs such as Guy Verhofstadt insist that Parliament will not accept anyone who is not a Spitzenkandidat.
“The group leaders are finding it even harder than expected to reach agreement on a compromise candidate. At the moment, it is anyone’s guess as to who this person, he or she, might be” European Parliament insider
The EPP again emerged as the biggest single group after the May elections and its candidate is German MEP Manfred Weber.
Some, such as French President Emmanuel Macron, have suggested that Weber has insufficient experience for the post and this is thought to have left him struggling to gain enough cross-party support.
Momentum is thought to be growing for a female Commission President, with support for Vestager, the Danish Competition Commissioner, gaining traction in recent days.
The Socialist candidate is another EU Commissioner, Frans Timmermans, but there is a school of thought that a non-Spitzenkandidat – such as Michel Barnier, the EU’s chief Brexit negotiator - could yet emerge as the best choice for EU leaders.
A Parliament insider told this website, “The group leaders are finding it even harder than expected to reach agreement on a compromise candidate. At the moment, it is anyone’s guess as to who this person, he or she, might be.”
Just ahead of the summit, Council President Donald Tusk said he was “cautiously optimistic” about the ability of heads of state and government to reach an agreement on the candidates for the leadership posts at the meeting.
In a letter to leaders, he said that his consultations with them “have shown that there are different views, different interests, but also a common will to finalise this process before the first session of the European Parliament [on 2 July],” adding, “To this end, I will continue to consult you one by one up until the summit starts.”
The summit will also touch upon the EU’s Strategic Agenda for the next five years that could see the entire bloc adopt a target of going carbon neutral by 2050.
The European Commission has called for a climate-neutral Europe by 2050 in its long-term strategic vision, “A Clean Planet for All”.
Most Member States want the 2050 target included in the EU’s strategic agenda.
Some countries have already pledged to go further, with Finland’s new government adopting a 2035 goal, and Labour proposing a 2030 goal for the UK.
EU officials say the “overwhelming majority” of Member States - thought to be at least 22 out of 28 countries - have now agreed to the climate change plan in behind-the-scenes talks ahead of the summit.
But some Member States in central and eastern Europe were still against the proposal ahead of the summit.
One senior EU official said, “the mood is changing in the Council”, adding: “At this stage we are talking about the overwhelming number of Member States that would be ready to accept the objective.”
But the official added, “There is still no unanimity, and I think this will be the issue for this working session on the first day.”
On 18 June, the European Commission published recommendations for each EU country's draft plans for how they will meet the EU's 2030 climate and energy targets.
On 25 June, EU national governments are due to decide on future EU budget for investments in climate action.
If adopted this week, the 2050 policy would represent a major step forward in the fight against climate change because it would be by the world’s second-largest economy.
Speaking ahead of the summit, Wendel Trio, director of Climate Action Network (CAN) Europe said, “EU leaders cannot neglect the UN Secretary General's call for more action to tackle the climate emergency.”
The European Council needs to commit to achieving net zero emissions and increasing the 2030 climate target, in line with the Paris Agreement's objective to limit temperature rise to 1.5°C.”
“Delaying this decision would leave the EU empty-handed at the September Climate Action summit and would be a major blow to the EU's international reputation as a climate leader.”
Further comment came from Anelia Stefanova, programme director of CEE Bankwatch Network, who said: “It is only a few Eastern European countries like Bulgaria and Poland that still want to postpone a decision on increasing the EU’s climate action, despite the fact that it is in their best interests.”
Elsewhere, Brook Riley, head of EU public affairs at Rockwool International, said, “The clock is ticking on climate change. It’s very clear that going climate neutral by 2050 is the only acceptable outcome.”