For two years, it was the coronavirus pandemic. Then, it was Russia's war in Ukraine. Throughout it all, the perils of climate change, poverty and inequality have steadily, increasingly thrummed through each convening of world leaders at the UN General Assembly.

As the 78th session opens, there's no single clear crisis set to dominate the General Debate, as none of the aforementioned ones have been resolved. The high-level meeting will be set against the backdrop of an ongoing war, new political crises in West Africa and Latin America, a lingering coronavirus, economic instability, widening inequality and fresh natural disasters in the forms of devastating earthquakes,floods and fires.

Rebuilding trust

In the face of this tumult, the theme for this year's General Debate will be "Rebuilding trust and reigniting global solidarity: Accelerating action on the 2030 Agenda and its Sustainable Development Goals towards peace, prosperity, progress and sustainability for all."

Heads of state and government from at least 145 countries are expected to take the dais at the river's edge. Among them will be Brazilian President Luiz Inácio Lula da Silva, U.S. President Joe Biden and Ukrainian President Volodymyr Zelenskyy — all expected in the first day. This will be Zelenskyy's first in-person appearance at the United Nations since the Russian invasion of his country — in 2022, the General Assembly voted to grant him special dispensation to submit a pre-recorded speech.

Key absences

But the parade of speakers will be marked by some key absences: While they're all sending representatives, the leaders of the rest of the permanent U.N. Security Council members — France, the United Kingdom, China and Russia — will not make the trip. The presence of Vladimir Putin would certainly have been surprising, but Emmanuel Macron is a regular attendee and this would have been British Prime Minister Rishi Sunak's first opportunity to address the General Assembly. Macron cited King Charles III's imminent visit; Sunak, a busy schedule.

Top leaders from other major countries, including India — who just played host to the G20 summit in New Delhi this month — and Mexico, are also slated to send ministers in their steads to the six-day meeting.