Putting a tax on carbon could be an effective approach for curbing global warming pollution.

Putting a tax on carbon could be an effective approach for curbing global warming pollution.

Though every nation must do its part to address climate change, developed nations are responsible for the lion's share of carbon pollution in the atmosphere, and they have an obligation to help developing nations transition to a sustainable future.

Though every nation must do its part to address climate change, developed nations are responsible for the lion's share of carbon pollution in the atmosphere, and they have an obligation to help developing nations transition to a sustainable future.

Countries have made impressive pledges to cut carbon pollution, but we have to ensure these promises become actions.

Countries have made impressive pledges to cut carbon pollution, but we have to ensure these promises become actions.

Whether it is salt farmers in India embracing solar power or wind companies creating tens of thousands of jobs in America, people are providing a vision for the clean energy future.

Whether it is salt farmers in India embracing solar power or wind companies creating tens of thousands of jobs in America, people are providing a vision for the clean energy future.

Mercury is a potent toxin that interferes with the human nervous system. Reducing this hazard will be a major public health breakthrough.

Mercury is a potent toxin that interferes with the human nervous system. Reducing this hazard will be a major public health breakthrough.

A cap on carbon is important because it sets a specific goal for reducing carbon emissions 80% by 2050.

As heat rises, so does the number of people trying to cool down homes, schools, hospitals and businesses. This isn't just about comfort; it's a matter of public health.

Studies show that women are more likely than men to die in natural disasters. Women's voices must be heard.

The oceans produce up to 70 percent of our oxygen, they shape our climate, and they support an American oceans economy larger than our nation's entire agriculture sector.

Pollution from oil and gas development, toxic runoff, and miles and miles of plastic trash foul the waters and threaten marine life.

I have long understood that climate change is not only an environmental issue - it is a humanitarian, economic, health, and justice issue as well.

I attended the climate talks in Copenhagen in 2009, and back then, national governments waited until days before to submit climate plans, and the U.S. based its pledge on a proposed bill that would fail in the Senate.

Americans are already paying the price for record heat waves, dirty air, and an unstable climate. We need to fight these threats with every weapon we have, and the electricity industry has to do its fair share.

The fossil fuel industry commands outsize sway over U.S. politics, markets, and democracy. I knew these companies were formidable, but when I served on the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, I got a close up view of how the industry disregards government safeguards.

I have visited people whose health has been endangered by tar sands oil. I have watched neighbors struggle to recover from Superstorm Sandy. I have seen solar panels and wind turbines become an increasingly familiar part of the landscape.

VW has held a beloved place in American culture. When I graduated from college, many of my friends drove across the country, and most hit the road in a VW van or Bug. Through the years, these cars have represented youth, freedom and quirkiness.

In the end, the market will decide which is the better performer: dirty coal-fired power or clean wind and solar. Market-based competition. That doesn't sound like communism to me.

I have been fighting climate change for two decades, and people often ask me how I remain hopeful in the face of extreme weather and grim forecasts. The answer is simple: I see countless solutions spreading across the nation and across the world. But we need more investment.

Though many corporations honor commitments to reduce dangerous pollution, some cut corners and cheat. The marketplace doesn't always have mechanisms to correct bad actors.