But, regardless of the backgrounds and sensibilities of his audiences, he sometimes tosses out ideas that challenge conventional thought.
His doctoral degree gave him the intellectual chops to explain the science of climate change, yet friends say his open mind is what allows him to hear new ideas. It is his spiritual side, colleagues say, that really sets him apart from your garden-variety academic.
Like when he talks about exploring a multidimensional world that we cannot see or hear.
"I joke with my friends that I'd like to demonstrate as a scientist that love is a real energy. That love can run a light bulb," the now-divorced Shearer said while sitting in his Financial District office. "And they say to me, 'David, how are you going to do that?' And I say, 'I don't really know, you guys, but as a scientist I need to be open to new ideas, and maybe it resides in one of these other dimensions.'
"Lately, as I talk about climate change, I lay out the picture - this is where we are, this is what the solution packages are - but really what it gets down to is cooperation, conversation and, dare I say, love. It gets down to having dialogues across countries, across societies."
Journalist Joe Garofoli concluded the piece with an appropriately upbeat quote from Shearer.
"While we need to be very sanguine about what the problems are on the planet, we need to create exciting, realistic, solution packages that capture the imagination," he said. "It's just too dire without creating some excitement.