WARSAW—Russian actions concerning gas supply have made advocates of the European Union’s plan to tackle climate change look “ridiculous,” the leader of Poland’s ruling party said in an interview published on Wednesday. Poland has called for the bloc to cancel or delay parts of its “Fit for 55” plan to tackle climate change ahead of a summit at which EU leaders will wrangle over their response to surging gas and electricity prices. “After the Russian action concerning gas, the creators and advocates of this ‘Fit for 55’ have, to put it delicately, made themselves look ridiculous,” Jaroslaw Kaczynski told Gazeta Polska weekly. “Energy prices have hit many EU countries with such force that their citizens will simply not agree to further increases in the name of some unproved theory.” Kaczynski did not specify exactly which Russian actions he was referring to. “Fit for 55” refers to the EU policy package …