Germany declared on Wednesday an “early warning” that it could be heading for a gas supply emergency and said the measure was designed to prepare for a possible disruption or stoppage of natural gas flows from Russia. The move comes ahead of Moscow’s plan to present a new mechanism under which gas payments will be switched to roubles, a move that has been rejected by the G7 nations, including Germany, but stoked fears of supply disruptions. Under Germany’s existing gas emergency plan, the early…