More than 50 nations are attending a world-first conference on phasing out fossil fuels in Colombia next week as the Iran war underscores how dependent countries remain on planet-heating coal, oil and gas.

The gathering was born out of frustration with consensus-based United Nations climate talks, where efforts to negotiate a fossil fuel exit strategy have stalled.

Major fossil fuel producing nations Australia, Canada and Norway are expected along with developing oil giants Angola, Mexico and Brazil and coal-reliant emerging markets Turkey and Vietnam.

However the world's biggest coal, oil and gas producers -- notably the United States, China, Saudi Arabia and Russia -- are skipping the event.

Tensions boiled over at COP30 in Brazil in November when nations could not even agree to include an explicit reference to fossil fuels in the final deal.