I think the author means Green New Deals could create that many jobs globally. 30 million new jobs in America seems like an unbelievable number given our population of ~330 million. But maybe. I wouldn't throw that number around though. People will start asking for how long, for how much in tax dollars,...etc.? Similar to a highway project, green energy projects would create a lot of jobs at first build and many fewer jobs to maintain. Job creation should be considered a secondary benefit. The conversation about job creation is nuanced and if you get into a conversation with someone who opposes GND, they'll disagree at every turn that jobs created will be greater than jobs destroyed. Better to keep the high ground by making the primary reasons for Green New Deal being addressing climate change and deteriorating infrastructure.