The two issues are primary concerns of the Global South, many countries of which face a severe financial crunch in meeting the challenges, while their problems have been exacerbated by the Covid pandemic and Russia’s invasion of Ukraine.

Secretary-General Antonio Guterres will push the industrialised countries to increase their funding for the causes of development and climate change.

They start their week of packed programmes on Monday with the summit on the UN’s Sustainable Development Goals (SDGs), the 17 lofty ambitions hoping to cure the world's ills from poverty and hunger to climate change and inequality, while bringing about peace and justice by 2030.

Guterres said that he considers the SDGs meeting "my most important objective" for the week.

"I’m very hopeful that the SDG Summit will indeed represent a quantum leap in the response to the dramatic failures that we have witnessed until now in relation to the implementation of the SDGs", he said at a news conference previewing the high-level week.

The SDGs were adopted by world leaders in 2015 and as they meet on Monday halfway to 2030, they will find most are unreachable by the deadline and will need reinvigorated commitments, especially from the industrialised nations.

Symbolically, this meeting starts a day before the traditional General Assembly meeting which will begin by tradition on Tuesday, with the first address by Brazil’s President Luiz Inácio Lula da Silva, to be followed by President Joe Biden.

Biden will be the only top leader of a permanent member of the Security Council this week at the UN.

Presidents Xi Jinping of China, Vladimir Putin of Russia and Emmanuel Macron of France, and Prime Minister Rishi Sunak of Britain are skipping the summits, as is Prime Minister Narendra Modi of India.

Asked about the striking absences of the leaders of the Council permanent members, Guterres said, "This is not a vanity fair".

What matters is not their presence, but their governments’ commitments, he said.

The General Assembly meeting is more political and Russia’s invasion of Ukraine will figure prominently there.

President Volodymyr Zelensky will be there in person this time – a much-adulated figure – after having been given a special dispensation last year to speak through a video link.

He will speak during the opening session of the Assembly meeting, and the next day at the Council’s meeting on Ukraine, where he will likely come face to face with Russia’s Foreign Minister Sergey Lavrov as he makes his
stinging denunciation of Moscow.

The spotlight turns next to climate change on Wednesday.

Guterres convened the Climate Ambition Summit to turbocharge action and funding to meet what he has repeatedly called the "existential threat" to humanity.

He has demanded that all leaders, especially those from the industrialised countries, leave aside rhetoric and come with concrete plans and commitment for keeping global warming under 1.5 degrees Celsius.

"This is not a time for posturing or positioning.  This is not a time for indifference or indecision. This is a time to come together for real, practical solutions", he said.

As with development, Guterres seeks to involve the private sector in fighting climate change.

Representatives of businesses will be participating at several events throughout the week on the two topics.