Just in the last few months, a cascade of climate-addled weather disasters has killed thousands, displaced millions and caused billions in damages: massive flooding in Pakistan and Nigeria, deepening droughts in Africa and the western US, cyclones in the Caribbean, and unprecedented heat waves across three continents.
"Report after report has painted a clear and bleak picture," said UN chief Antonio Guterres in the run-up to the 13-day conference in the Red Sea resort of Sharm el-Sheik.
"COP27 must lay the foundations for much faster, bolder climate action now and in this crucial decade, when the global climate fight will be won or lost."
Concretely, that means slashing greenhouse emissions 45 percent by 2030 to cap global warming at 1.5 degrees Celsius above late-19th-century levels.
Warming beyond that threshold, scientists warn, could push Earth toward an unlivable hothouse state.
But current trends would see carbon pollution increase 10 percent by the end of the decade and Earth's surface heat up 2.8C, according to findings unveiled last week.
Promises made under the Paris Agreement would, if kept, only shave off a few tenths of a degree.
"Our planet is on course for reaching tipping points that will make climate chaos irreversible and forever bake in catastrophic temperature rise," Guterres said recently.
"We need to move from tipping points to turning points for hope."
Heads of state and government will attend the Sharm el-Sheikh Climate Implementation Summit on November 7 and 8. The high-level segment primarily attended by ministers will take place from November 15 to 18.
For the UN climate forum, that means transitioning from negotiations to implementation.
It also means a shift from politics to the economy, with government investments in China, the US and the European Union leveraging hundreds of billions of yuan, dollars and euros into trillions.
The already daunting task of decarbonizing the global economy in a few years has been made even harder by a global energy crunch and rapid inflation, along with debt and food crises across much of the developing world.
"There have been fraught moments before," said E3G think tank senior analyst Alden Meyer, recalling other wars, the near collapse of the UN-led process in 2009, and Donald Trump yanking the United States out of the Paris Agreement in 2016.
"But this is a perfect storm," dubbed by some a "polycrisis", said the 30-year veteran of the climate arena.
After front-line negotiators set COP27 in motion on Sunday, more than 120 world leaders will put in appearances on Monday and Tuesday.
Saudi Arabia will dispatch six ministers to the summit, including Energy Minister Prince Abdulaziz bin Salman and Envoy for Climate Affairs Adel Al Jubeir.
The most conspicuous no-show will be China's Xi Jinping, whose leadership was renewed last month at a Communist Party Congress.
US President Joe Biden has said he will come, but only after legislative elections on Tuesday that could see either or both houses of Congress fall into the hands of Republicans hostile to international action on climate change. He will visit Sharm el-Sheikh on November 11.
Cooperation between the United States and China -- the world's two largest economies and carbon polluters -- has been crucial to rare breakthroughs in the nearly 30-year saga of UN climate talks, including the 2015 Paris Agreement.
In a welcome message ahead of the summit, COP27 President and Foreign Minister Sameh Shoukri said: "Climate change is no doubt the challenge of our times, and the international community is hence called upon to deal with this challenge collectively, effectively and rapidly."
"In Glasgow we succeeded in concluding for the most part the extensive negotiations to operationalize the Paris Agreement, we must now set our attentions on the full implementation of the Agreement and on the delivery of the various commitments and pledges made," he added.
"The most reliable science available in the form of the recently published IPCC reports paints a sobering picture, and highlights the urgent need to significantly raise our ambition with regard to emissions reduction, in tandem with the need to effectively adapt to the negative impacts of Climate change," he continued.
"The reports also reminded us of the need to provide and mobilize necessary financial support from public and private sources, along with other means of implementation in the form of technology and capacity building if we are to ensure that developing countries are in a position to make the necessary contribution to this global effort."
"We in Egypt truly believe that the political will demonstrated in Glasgow allowed us to successfully complete our work on the Paris Agreement Work Program, and to announce a broad range of commitments and pledges," he stressed.
"We trust that this political will and genuine commitment will once again be on display in Sharm el-Sheikh and will facilitate making the progress we all aspire to."
"And while many governments have stepped up their action and others will hopefully follow suit in the near future, the fact remains that this global effort requires contributions from and collaboration with all non-party stakeholders across the board," said Shoukri.
"We commit to all parties to exert all efforts to create an environment conducive to reaching consensus on negotiating texts," he added.
"This in our view requires a less adversarial and more empathetic approach in dealing with issues at hand, and we trust that all parties will appreciate that our chances of success, collectively, are greatly enhanced when every country, group and community feels that their interests and concerns are taken on board."