It's Earth Day. It's Good Friday. It's a three-day Easter weekend.

And Americans are depressed.

Despite a rising stock market, despite falling unemployment, most Americans feel the economy is going into the tank. 

The reason: high gas prices.

For those who did their efficiency homework years ago (which probably includes many readers of this site) high gas prices are no big deal. In fact, evidence suggests we're weathering this bout much better than in the past, thanks to efficiency technologies, where America has a lot more room to grow than its economic rivals.

Still, it's time we change the frame of the debate, starting with this Earth Day.

Since its launch in 1970 by then-Senator Gaylord Nelson, Earth Day has always been about limits, about the need to “conserve,” in order to save the planet. To make do with less. To limit.

That's a tough sell in America although, thanks to new insulation, motors, and lighting, it's actually producing growth that offsets higher prices.

But if you're looking for real growth, a more abundant life for our children and grandchildren, this industry is the place where you'll find it.

My message for this Earth Day is that it's time for mankind to become truly civilized. Instead of acting like cavemen, looking for stuff to burn, and defining wealth by how much stuff we can burn, it's time to become farmers, and harvest the abundance all around us, as every renewable company is doing.

The message is simple enough for a bumper sticker.

There is no energy shortage.

The Sun shines. The wind blows. The tides roll. We live on a molten rock.

What we've been short of, until now are the tools to harvest all this abundance, the equivalent of scythes and plows in ancient Sumeria.

One way to celebrate Earth Day in the right way is by pointing to breakthroughs all along the supply chain, from the laboratory to the factory to the field.

Take this study from Wake Forest, showing how the heat hitting our roofs can be harnessed by new materials. Or this report, from the Berkeley National Laboratories, showing that homes with solar panels fetch higher prices than those without them.

Politicians (and former politicians) have gotten the message and begun evangelizing for clean energy. It's a growth message. That makes it a winning message.

And that's the message we need to take out of this Earth Day. Let's finally end the hunter-gatherer era. Let's harvest the abundance all around us. Instead of complaining about the scarcity of burnable stuff, let's celebrate growth and plan for a richer tomorrow.