SHARM EL-SHEIKH, Egypt — World leaders took to the stage on the opening days of the U.N.’s flagship climate summit to insist Russia’s onslaught in Ukraine must not derail urgent and collective action to prevent catastrophic global heating.

In the run-up to the COP27 summit, which got underway on Sunday, it had been suggested that geopolitical crises, soaring inflation and a looming economic recession could distract policymakers from taking measures to avoid the worst effects of human-induced climate change.

World leaders on Monday and Tuesday convened in Egypt’s Red Sea resort town of Sharm el-Sheikh to deliver national statements on the battle to secure a livable future.

“Climate security goes hand in hand with energy security,” U.K. Prime Minister Rishi Sunak said at the U.N.-brokered talks.

Russian President Vladimir Putin’s “abhorrent war in Ukraine and rising energy prices across the world are not a reason to go slow on climate change. They are a reason to act faster,” Sunak said on Monday.

“Because diversifying our energy supplies by investing in renewables is precisely the way to insure ourselves against the risks of energy dependency.”

A flurry of major U.N. reports published in recent weeks delivered a bleak assessment of how close the planet is to irreversible climate breakdown, warning there is “no credible pathway” in place to cap global heating at 1.5 degrees Celsius.

The 1.5 degrees Celsius limit is the aspirational temperature threshold ascribed in the landmark 2015 Paris Agreement.

It is recognized as a crucial global target because beyond this level, so-called tipping points become more likely. These are thresholds at which small changes can lead to dramatic shifts in the Earth’s entire life support system.

“We will not sacrifice our climate commitments under the energy threat from Russia and therefore all of the commitments made by nations must be held,” French President Emmanuel Macron said from Sharm el-Sheikh on Monday.

He also talked about the need for “energy sobriety” to transition away from fossil fuels and said countries in the global north and south “must come to terms with the idea of financial solidarity.”

Antonio Costa, prime minister of Portugal, said Tuesday that the European country started to invest in renewables 15 years ago and was now an example of how investing in the transition away from fossil fuels meant it was safer from a fuel emergency.

Costa also said Portugal had abandoned coal eight years earlier than planned and does not expect the fallout from the Ukraine war to cause it to reverse this decision.

“We cannot backtrack on our commitments,” Costa said, according to a translation.

A study published last month by energy think tanks E3G and Ember showed that wind and solar produced a quarter of the European Union’s electricity since Russia’s war in Ukraine began in late February, with record growth estimated to have avoided the need for 8 billion cubic meters of gas at a cost of $11 billion euros ($11 billion).

In addition to the climate benefits of shifting away from gas, a fossil fuel, analysts at E3G and Ember said this shows that “accelerating deployment of cheap renewable energy will reduce Europe’s exposure to costly fossil fuels.”

At the same time, Russia’s invasion of Ukraine has threatened to derail the bloc’s decarbonization goals. Some European governments have been prompted to reconsider coal, one of the dirtiest and most polluting ways of producing energy, following a sustained period of reduced flows of Russian gas.

Germany, Italy, Austria and the Netherlands have all indicated that coal-fired plants could be used in the short term to compensate for a cut in Russian gas supplies. European countries have also announced plans to build new liquefied natural gas terminals and extend the region’s network of gas pipelines.

U.N. Executive Secretary Antonio Guterres said at COP27 on Monday that “the war in Ukraine, conflict in the Sahel, and violence and unrest in so many other places are terrible crises plaguing today’s world.”

“But climate change is on a different timeline and a different scale. It is the defining issue of our age,” he added.

Guterres warned that it would be “unacceptable, outrageous and self-defeating” to put climate action on the back burner, highlighting that many conflicts around the world were linked with “growing climate chaos.”

“The war in Ukraine has exposed the profound risks of our fossil fuel addiction,” he continued. “Today’s urgent crises cannot be an excuse for backsliding or greenwashing. If anything, they are a reason for greater urgency, stronger action and effective accountability.”