The United Nations is closing in on a decisive moment: in a sealed chamber beneath its New York headquarters, fifteen diplomats will soon reveal who will become the next secretary-general. The choice arrives at a time when two permanent Security Council members – the United States and Russia – are locked in open conflicts, while the world grapples with a climate emergency that threatens to overwhelm every humanitarian system.
Beyond the diplomatic drama, a separate scientific assessment released this week paints an equally stark picture. Researchers from the Potsdam Institute have declared that seven of the nine planetary boundaries are now breached at historic levels, signaling that humanity is operating outside the safe zone that once guaranteed stable ecosystems.
UN leadership election amid wars and a splintered multilateral order
The upcoming vote is unlike any in the organization’s eight-decade history. The five permanent members – the United States, United Kingdom, France, Russia and China – retain a veto, meaning any candidate must win the assent of leaders such as Xi Jinping, Vladimir Putin and, crucially, President Donald Trump. Trump’s recent establishment of a “Board of Peace” and his administration’s withdrawal from 31 UN bodies, including climate and women’s-health agencies, have left the institution financially fragile and politically isolated.
Three informal straw polls have already taken place, yet neither of the leading contenders – former Guyanese foreign minister Carolyn Rodrigues-Birkett nor ex-Vice President of Costa Rica Rebeca Grynspan – has secured a decisive edge. Even the United Kingdom and France have registered no support for any candidate, hinting that the “Permanent Five” could stall the process entirely.
Planetary boundaries shattered: a scientific wake-up call
The latest planetary-health report confirms that seven of the nine critical thresholds – including climate changebiosphere integrityland-system changefreshwater usebiogeochemical flows the spread of novel entities and, for the first time, ocean acidification – are now in the danger zone. Only stratospheric ozone depletion and atmospheric aerosol loading have shown modest improvement over the past decade.
Lead author Boris Sakschewski warns that “pressure is rising across every planetary boundary already outside the safe operating space”, meaning the risk of irreversible change is climbing while our margin for corrective action shrinks. Climate scientist Johan Rockström adds that humanity still possesses the knowledge and capacity to steer back into a safe zone, but only if decisive, coordinated action is taken immediately.
War, military emissions and the UN’s shrinking capacity
While the climate report focuses on emissions from industry, transport and energy, a growing body of research highlights the missing piece: the greenhouse-gas output of militaries. Neta C. Crawford’s recent study underscores that no comprehensive accounting exists for the carbon footprint of wars, weapons production and post-conflict reconstruction, despite these activities accounting for a substantial share of global emissions.
This oversight matters because the UN is the sole body capable of measuring, reporting and, ultimately, regulating such emissions. Its climate-negotiation platform, the Framework Convention on Climate Change, continues to convene the world’s leaders, yet the organization fights a parallel financial crisis, with the United States behind on dues that threaten “imminent financial collapse”. The upcoming secretary-general will therefore inherit a dual mandate: to revive multilateral cooperation on security and to embed climate accountability – including military emissions – into the UN’s agenda.
What the next secretary-general must confront
The candidate who ultimately wins must navigate three intertwined crises. First, the ongoing wars in Ukraine and the Middle East demand a leader who can mediate without alienating the United States or Russia. Second, the planetary-boundary breach forces the UN to push for rapid decarbonisation, stricter enforcement of climate accords, and perhaps the creation of a monitoring system for militaries’ carbon footprints. Third, the organization’s own financial insolvency requires diplomatic skill to coax overdue contributions, especially from the United States, while preserving the agency’s core programmes such as peacekeeping, humanitarian coordination and climate finance.
With the General Assembly’s climate-focused week already underway in New York, figures like former Irish President Mary Robinson and Nobel laureate Juan Manuel Santos have attended the launch of the planetary-health report, underscoring the urgency. Yet the same week also hosts the UN’s high-stakes election, a moment that will determine whether the institution can rise to meet the planet’s most pressing challenges or descend further into irrelevance.
