Going 'Zero Carbon' Is All The Rage. But Will It Slow Climate Change?

The warnings come with unsettling regularity:

Climate change threatens 1 million plant and animal species.

Warmer oceans could lose one-sixth of their fish and other marine life by the end of the century.

Global warming is a major risk to the economy.

The world's leading scientists have made it clear that to prevent the worst effects of climate change, there needs to be "rapid, far-reaching and unprecedented" changes to our energy systems. In simpler terms: We need to stop adding carbon dioxide to the atmosphere.

Federal action to curb greenhouse gas emissions in the U.S. seems unlikely in the near future. The Trump administration is going the other way, rolling back regulations to cut emissions.

But a growing number of cities, states, electric utilities and businesses are recognizing the risk presented by climate change and making their own pledges to reduce emissions.

Just in the past year, three states —