Officially the G20 summit in Brisbane this weekend will focus on reviving the global economy, in particular through infrastructure projects. But such jamborees are hostage to events, so the climate-change agreement struck by Barack Obama and Xi Jinping at another big summit this week—the APEC shindig in Beijing—will feature, too. That will irk Tony Abbott, Australia’s prime minister and the G20’s host, who downplays global warming. Even more awkwardly, he must welcome Vladimir Putin (though Mr Abbott may decide not to greet Russia’s president with a “shirtfront”, a bellicose sporting manoeuvre he once said he would attempt). Mr Abbott justly blames Russia for the shooting down of flight MH17 in July, in which 28 Australians died. In Beijing he asked for an apology; Mr Putin refused. The escalating fighting in Ukraine may also intrude. Meanwhile Russia has softened up its host in the traditional way: by sending warships towards Australian waters.