Not a financial expert, but i think reduce implies it goes away, and absorb implies it’s still there but someone is taking it up.
Like reducing the amount of water on the floor would be turning off the tap. Absorbing the amount of water on the floor is when you mop it up.
That’s exactly what I meant. I was only replying to the question as posed.
Or to bring it back to the original context... Reducing volatility would be reducing the impact of bad weather on your harvest, absorbing volatility is finding someone to cover your losses. (presumably by giving up some profits on the good years. It's like a financial low pass filter)