Earth tones

Albert Einstein claimed, "We shall require a substantial new way of thinking if we are to survive." Well, duh . . . This weekend's "Down:2:Earth" expo offers a good opportunity to kick-start that cerebral sea change. The eco-conscious event features products that combine sustainability with style and innovation (at right, Sustainably Minded Interactive Technology's "ivy" that provides power via sun and wind). Tomorrow's keynote speaker, at 4 p.m., is Bill McKibben, noted environmentalist and author of "The End of Nature," the first major book on global warming. Sunday's keynote speaker, at 3 p.m., is Frances Moore Lappé, author of the visionary "Diet for a Small Planet." Fri. 5-10 p.m., Sat. 11 a.m.-8 p.m., Sun. 11 a.m.-5 p.m. $8-$20. Hynes Convention Center, 900 Boylston St., Boston. 617-266-6540. d2eboston.com