Environment and Public Works Chairwoman Barbara Boxer tried to extend an olive branch to Republicans on climate change Monday evening, extending a deadline for them to offer amendments to her global warming legislation. But even as she made new advances, Boxer (D-Calif.) vowed to continue with her controversial mark-up, with or without GOP support. “Right now it is essential we keep the process moving forward and that’s what we’ll do,” said Boxer. The seven Republicans on the committee plan to boycott a Tuesday legislative hearing about the bill unless Boxer agrees to wait for additional economic analysis of the bill....