COP26 live updates: World leaders arrive in Glasgow for high-stakes climate summit

Away from the spotlight, officials will be working to finalize the Paris agreement’s “rule book,” which would strengthen the 2015 agreement. While officials worked out many details at earlier summits, some key issues remain unresolved, including the complex and contentious rules that govern global carbon markets — a topic that has tripped up negotiators at the last two U.N. gatherings, in Poland and Madrid.