Candidates for the 2020 Democratic Party nomination for president presented a series of aggressive climate change plans. 

Climate change—for years a focus in California—is shaping up to be a central theme in a U.S. presidential election for the first time and was the topic this week of a grueling seven-hour public town hall on the CNN television network among Democratic candidates.

Ten leading candidates for the Democratic nomination laid out a series of proposals at the Sept. 4 town hall, many of which might have been considered extremely radical just a few years back. These include banning offshore drilling, hydraulic fracturing, internal combustion engines and all coal-fired and nuclear power, as well as achieving 100 percent decarbonization of the U.S. power and transportation systems a little over a decade from now.

Meat consumption, airplane travel, agricultural practices, and light bulbs are other aspects of everyday American life that are raising more questions in the mainstream conversation on energy and climate change, with California the epicenter of the movement.

This week saw a flurry of climate plans dropped by candidates in the lead-up to the town hall, including Sen. Kamala Harris (Calif.), Sen. Cory Booker (N.J.), Sen. Amy Klobuchar (Minn.), former U.S. Secretary of Housing Julián Castro, and Sen. Elizabeth Warren (Mass.). 

A good portion of the Democratic field supports a carbon tax, including Harris, Warren and South Bend, Indiana Mayor Pete Buttigieg. But candidates Sen. Bernie Sanders (Vt.) and former Sen. Joe Biden (Del.) have stayed away from a carbon tax, which has long been an unsuccessful effort in Congress.

The stage is set for the next presidency to be one of two extremes: either a Democrat who will apparently call for unprecedented changes in lifestyle and practices for Americans and industry on a fast timeline, or a continuation of President Donald Trump's unabashed support for fossil fuels and increased domestic production of natural gas and coal.

The much-ballyhooed CNN town hall came as climate change is foremost in the public conversation, cited as a cause of Hurricane Dorian and its related widespread flooding, as well as fires burning in the Amazon rainforest. And 16-year-old Swedish climate change activist Greta Thunberg sailed across the Atlantic Ocean on a low-carbon journey to publicize her speech at the upcoming United Nations Climate Action Summit in New York City on Sept. 23.

Political momentum on climate change has been growing in the wake of the "Green New Deal" promoted by Rep. Alexandria Ocasio-Cortez (N.Y.). Political candidates and localities have announced their own versions of a GND, and Washington Gov. Jay Inslee, who made climate change his central issue, withdrew from the presidential race, but his ideas live on in other candidates' platforms.

For Sanders, curbing population growth in third-world countries is a key feature of his $16.3-trillion climate plan, as is an end to "factory farming," according to his comments at the town hall. Sanders' version of the Green New Deal includes attaining 100 percent renewable energy for electricity and transportation by 2030 and complete decarbonization of the country by 2050 at the latest, as well as "ending unemployment by creating 20 million jobs needed to solve the climate crisis," his website says.

"There will be a transition, and there will be some pain there," Sanders said at the town hall.

Warren at the town hall said no new nuclear power plants would be built under her administration. She announced her multitrillion-dollar plan the day before the town hall, pulling in Inslee's proposals.

Biden at the debate mentioned getting "combustion vehicles off the road as rapidly as we can" and shutting down existing coal-fired power plants. His $1.7-trillion plan announced in April aims for a "100 percent clean energy economy" and net-zero emissions no later than 2050.

Harris at the debate said she would ban offshore drilling and hydraulic fracturing, or "fracking," and declared she would eliminate the filibuster in order to pass climate change legislation. Her climate plan calls for 100 percent carbon-neutral electricity by 2030, and stipulates that all new buses, heavy-duty vehicles, and vehicle fleets will be zero-emission, and all new buildings will be carbon-neutral. Oil companies would pay for the harm they have caused to public and environmental health, her plan says.

In other ambitious goals discussed at the CNN town hall, tech entrepreneur Andrew Yang said he was in favor of "a carbon-free America." Also supporting a ban on offshore drilling was Beto O'Rourke (Texas), as well as Booker, who said: "We will transition off of fossil fuels—natural gas, coal."

The moral pressure on climate change has never been more in play in a debate, with Buttigieg stating at the town hall that "it's a life-or-death" issue.

"If you believe that God is watching as poison is being belched into the air of creation . . . what do you think God thinks of that?" Buttigieg said. "I bet he thinks it's messed up. At least one way of talking about this is, it's a kind of sin."

With such declarations, it is clear that the urgency has ramped up in the national conversation around climate change. The issue makes a choice between the two main political parties an easy one, based on one's views of the debate. And those views are becoming even more clear-cut between Democratic and Republican interests.

But time will tell if the radical changes to existing energy practices called for by Democratic candidates are viable, or only fantastic visions as they fall victim to the urge to promise too much, too quickly.