Yes, 2020 is on the horizon, and during this holiday season, Heavy Metal is getting contemplative. No that doesn't mean the Heavy Metal blog will turn into a Jim Brickman Christmas album — although the mellow pianist is from Metal's hometown of Cleveland.

So to borrow an idea from the classic mockumentary "This is Spinal Tap," let's turn the volume down from 11 to 10 and consider some year-end musings:

Plastics is under attack — especially the single-use kind. And so is global warming. Greta Thunberg, the 16-year-old climate activist who was just named Time's Person of the Year, is lecturing us older-generation people about how messed up the planet will be when she's our age, when all we really want to worry about is if we saved enough money for retirement.

My 18-year-old daughter texts back "OK Boomer" when Metal gives her advice that she doesn't like. It's the Generation Z version of our current president's "fake news." (And yes, in the spirit of a peaceful, quiet Christmas, the president is "He Who Must Not Be Named" in this holiday blog. After all, it's break time).

As the young people slam Generation X, we just keep getting older and grayer. Heavy Metal's son informs the Metallic One that "I don't like music with drums and guitars." No Led Zeppelin? Oh, where did Heavy Metal fail?

But this aging rocker does have some hip ideas. Here's the biggest one: We should rethink the idea of economic growth.

Going back to Heavy Metal's college days, the idea of unending growth based on ever-faster consumption of finite natural resources — coal, oil, natural gas and things like that — rubbed Metal the wrong way. At some point, it all falls apart.

Fast forward 35 years. Yes, we have plenty of oil, but automakers are working on electric vehicles. We have plastics in the oceans. And even if you don't agree with the many scientists who say global warming is caused by human emissions (and cow flatulence), you got to admit the weather seems awful extreme. Glaciers are receding.

Here's the point of this holiday blog: Heavy Metal says it's time to move beyond Gross Domestic Product as the only way to measure economic success. I know, GDP and the idea of an endless expansion of growth has been central to the world since the Industrial Revolution.

Global population keeps increasing, at the same time that nations need to reduce emissions. Plus, while GDP does measure physical output — like plastic parts, for example — it is not as good at measuring the service sector. Let's consider adding some other things to the idea of "growth," like clean air, healthier lives, community volunteer work. Measure them.

This goes far beyond the "circular economy," the Big Idea pounded home at the K 2019 show in Düsseldorf, Germany, this fall.

The idea is to come up with a new way to think about economic growth that gives a better future to Greta Thunberg — and my kids, and your kids, and your grandchildren and their grandchildren and on and on — long after we are gone from this Earth.