HARRISBURG, Pa. - Josh Shapiro, the Democratic candidate for governor, is breaking with Gov. Tom Wolf on the centerpiece of Wolf’s plan to fight climate change amid the strong and sustained pushback it has received from building trades unions that have long backed the party's candidates for governor.Wolf — a fellow Democrat who has endorsed Shapiro, the state's two-term attorney general — has worked for two years to finalize regulations to make Pennsylvania the first major fossil fuel state to adopt a carbon pricing policy by imposing a price on carbon dioxide emissions from power plants.Wolf has called it a "historic, proactive and progressive approach that will have significant positive environmental, public health and economic.