Kaiser Permanente to be carbon-neutral by 2020

Reality check: While Kaiser is a large system with more than 75 million square feet of hospitals and other real estate, that's a relatively small footprint. The land area of the city of Oakland, where Kaiser is headquartered, is about 1.6 billion square feet by comparison.

• However, shifting to renewable energy at hospitals would be particularly beneficial because they are intensive energy hogs.

Why now: "The massive fires that we're dealing with in California — I don't need to debate whether that's a climate issue," Tyson said, adding that climate change has direct and indirect effects on people's health.