Governments, industries, and societies must take radical measures to prevent global temperatures from breaching the 1.5-degree-Celsius warming limit set by the Paris Agreement and avert widespread calamities such as extreme heatwaves and ecosystem collapse, according to a United Nations Environment Program (UNEP) report launched in Nairobi on Wednesday.

The report "Limiting Overshoot: Navigating exceedance of 1.5 degrees Celsius and pathways towards return" warns that failing to curb runaway warming will plunge humanity into a perilous future marked by climatic shocks, hunger, disease outbreaks and economic collapse.

UNEP Executive Director Inger Andersen noted that while global temperatures are increasingly likely to exceed 1.5 degrees Celsius above pre-industrial levels in the near term, avoiding a permanent breach of the threshold remains entirely possible.

"Now is the time we must double down on climate action. We can – and must – get on the right path by cutting greenhouse gas emissions, strengthening resilience and adaptation, and ensuring that any exceedance of 1.5 degrees Celsius is as small and short-lived as possible," Andersen said.

She noted that preventing even a fraction of a degree of warming each year will save lives, protect fragile ecosystems and reduce economic losses.

Despite national net-zero commitments, the UNEP report warns that breaching the Paris Agreement's temperature threshold is increasingly likely, escalating risks of accelerated sea-level rise, coral reef collapse, catastrophic wildfires and glacier loss.

The report warns of an elevated risk of triggering irreversible tipping points such as the collapse of the West Antarctic and Greenland ice sheets, the Atlantic Meridional Overturning Circulation, and the Amazon rainforest, with catastrophic consequences for planetary stability.

Unabated emissions of greenhouse gases, including methane and carbon dioxide, could cause temperatures to continue rising, threatening small island developing states and low-lying coastal cities with partial or total submersion, the report notes.

The report says that runaway warming will drive up energy costs and insurance premiums, straining financial systems worldwide.

Stressing that a climate crisis is still preventable, the report emphasizes that nations must transition to clean energy while cutting emissions of methane and other short-lived climate pollutants.

Limiting temperature spikes will require simultaneous adaptation and mitigation efforts, backed by multilateral cooperation, political resolve, effective policies and sustained financing, according to the report.

The report calls for implementing simultaneous adaptation and mitigation measures, backed by multilateral action, political goodwill, effective policies, and sustained financing, to curb global temperature spikes.