



SEATTLE — Microsoft co-founder Bill Gates has endorsed a November ballot measure in Washington state that would charge a fee on carbon emissions from fossil fuels.



Gates wrote in a LinkedIn post Tuesday that he will contribute to the Yes on 1631 campaign and vote for it, saying "climate change may be the toughest problem humanity has ever faced."



The philanthropist cited several reasons for his support, including that the measure would help Washington state become a hub for innovative work on clean energy.



"If you want to be an innovator in this field—whether you want to do academic research, start a company, or both—you will want to do it here. That’s good for everyone in the state and ultimately will foster the companies and industries that will create tens of thousands of jobs in Washington," Gates wrote.



I-1631 would charge large polluters an escalating fee on fossil-fuel emissions starting at $15 per metric ton. It would be the first direct carbon fee of its kind in the U.S.



Opponents including top oil companies have raised more than $21 million to defeat it. They say it would hike gas and electricity costs and exempts too many big polluters.



The Associated Press contributed to this report.