Biden and Xi are glaringly absent from the UN's climate summit. That doesn't bode well for the world.

• World leaders are gathering in the UAE for the COP28 climate change summit. 
• But President Joe Biden and Xi Jinping of China will be absent.
• Their absence is an obstacle to meaningful action on climate change. 

World leaders are gathering today in the United Arab Emirates for the opening of COP28, the world's most important global warming summit.

King Charles and Pope Francis are attending alongside delegates from 200 nations.

Their core goal will be making better progress toward meeting the Paris 2015 UN Framework Convention on Climate Change to limit global warming to 1.5 Celsius a year above pre-industrial levels.