Sharm el-Sheikh, Egypt - World leaders on Monday opened a climate summit in Egypt with a call from UN chief Antonio Guterres for a "climate solidarity" pact between developed and emerging economies.

It would be "a pact in which all countries make an extra effort to reduce emissions this decade in line with the 1.5-degree [Celsius] goal," Guterres said at the summit in the Egyptian coastal resort of Sharm el-Sheikh.

"A pact in which wealthier countries and international financial institutions provide financial and technical assistance to help emerging economies speed their own renewable energy transition."

Guterres also sent out a stern warning: "We are in the fight of our lives. And we are losing. Greenhouse gas emissions keep growing. Global temperatures keep rising."

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The world is on a "highway to climate hell," he said. For him, humanity has a stark choice: "cooperate or perish."

The two-day climate summit in Sharm el-Sheikh, attended by dozens of heads of state and governments, is seen as a bid to provide much-needed political momentum for efforts to curb global warming.

The summit is being held a day after the start of a parallel UN climate conference, known as COP27, in the Red Sea resort.

Negotiators at COP27 are grappling with how global warming can still be contained and how to mitigate the financial costs of climate change, mainly for vulnerable countries.

The goal is to limit warming to 1.5 degrees Celsius, as stated in the 2015 Paris agreement.

Guterres said that this goal is "on life support and the machines are rattling."

The climate events are being held amid multiple crises surrounding food, energy, and rising inflation in economies across the world – exacerbated by the war in Ukraine – and expectations for major breakthroughs are seen to be low.

Climate-related disasters have meanwhile taken a huge toll on lives and livelihoods in several parts of the globe.

Egyptian President Abdel-Fattah al-Sissi, whose country has close ties with Russia, on Monday called for an end to the war in Ukraine.

"I’m making an appeal to stop this war," said al-Sissi without directly blaming Russia for starting the violence. He also called for "swift and effective" action on climate change.

"Our people expect us to take real, tangible steps towards reducing emissions and building capability for adaptation to consequences of climate change and providing the necessary financing for the developing countries," he said.

In 2009, the developed countries pledged to provide $100 billion a year in finance by 2020 for climate protection in poor countries. The pledge remains largely unfulfilled.

The talks in Egypt mark their return to the African continent after six years, with COP22 held in Morocco in 2016.