CNN's climate crisis town hall

CNN tonight hosted 10 back-to-back town halls with 2020 Democratic candidates.

The candidates took questions directly from a live studio audience — composed of Democratic voters interested in the issue — in New York as well as CNN moderators.

Here's the key takeaway from each candidate's town hall:

New Jersey Sen. Cory Booker said that people who don’t think nuclear power needs to be part of the fight against climate change -- a group that includes many of his presidential opponents -- “aren’t looking at the facts.”

Booker said that he warmed to nuclear power after reading studies about it and talking to nuclear scientists about technological advancements “that make nuclear safer.”

Vermont Sen. Bernie Sanders and Massachusetts Sen. Elizabeth Warren are both opposed – in different ways – to nuclear power.

Warren said Wednesday that she would oppose nuclear energy as a way to combat climate change should she be elected president in 2020.

“We’re not going to build any nuclear power plants and we’re going to start weaning ourselves off nuclear energy and replacing it with renewable fuels,” Warren said, adding that she hopes to phase out nuclear power by 2035.

New Jersey Sen. Cory Booker is a vegan -- but he says he won’t try to get other Americans to stop eating hamburgers.

Still, Booker said at CNN’s climate town hall Wednesday night that he would stop subsidies for corporate farming practices that contribute to pollution and global warming.

But, he said, he sees health care as extending beyond doctors and nurses to include healthy food systems.

“We are going to have to make sure our government is not subsidizing the things that make us sick and unhealthy and hurt our environment,” he said.

Booker, who said he became a vegetarian while playing college football at Stanford, said he visited a community in North Carolina where “the farming practices are becoming so perverse” that people there can’t open their windows, are seeing their creeks polluted and are suffering respiratory illnesses.

“There’s not a person in our country, seeing that misery, that wants to take a part in that,” he said.

New Jersey Sen. Cory Booker is the last 2020 candidiate to take the stage at CNN's climate crisis town hall.

He's taking voters' questions now.

Earlier tonight, these 2020 candidates participated in the event:

Former Rep. Beto O’Rourke said that, should he be elected president, his administration would spend federal dollars to help people in flood-prone areas move to higher ground.

Central to O’Rourke’s answer was Houston, Texas, where a series of floods have affected parts of the sprawling city, raising questions about whether people should rebuild in the same places that have already flooded multiple times.

He added: “That’s why under my administration we’re going to invest the resources that will allow people to move to safer ground, rebuild their homes, their businesses and their lives.”

O’Rourke made clear that this would be for people whose homes have “repeatedly flooded.”

“We should help people move when they need to move,” he said.

CNN's Chief Climate Correspondent Bill Weir asked Beto O'Rourke if the American diet has to change in order to combat the climate crisis.

"To grow one pound of beef, it takes 20 times the land and 20 times the carbon pollution as one pound of plant protein. So as president, how do you think the American diet should change?" Weir asked

O'Rourke said he rejects "any notion that we have to radically or fundamentally change how we eat or what we eat."

He continued: "I just think we have to be more responsible in the way that we do it, and the best way to do that is to allow the market to respond by setting a price on carbon in every single part of our economy, every facet of American life."

What’s the impact of meat production, anyway?

There's a lot for environmentalists to hate about beef. It's cattle ranchers, encouraged by Brazilian President Jair Bolsonaro, setting fires in the Amazon to destroy rain forest in order to make room for more meat production.

But there is also the matter of methane produced by cows. Livestock is responsible for more than 14% of greenhouse gas emissions — and beef in particular is responsible for 41% those. 

Democrats are proposing a shift to “sustainable” agricultural practices, but Republicans have mocked a line cut from a Democratic summary of the Green New Deal that mentioned “cow farts” and allege that Democrats want to take away Americans steaks and hamburgers.

Beto O’Rourke raised the prospect of Puerto Rican statehood at CNN’s climate town hall Wednesday. The former Texas congressman said the island should have the option of "two U.S. senators who can go to town for them" to fight for disaster-related funding.

Beto O’Rourke said he opposes a carbon tax and instead backs a carbon cap-and-trade program in which a shrinking number of “allowances” would be sold to polluters each year.

“It’s the best way to send the pricing signal to ensure that there is a legally enforceable limit,” the former Texas congressman said at CNN’s climate town hall Wednesday.

“We should certainly price carbon. I think the best possible path to do that is through a cap and trade system. There would be allowances granted or sold to polluters,” he said, adding that “there would be a set number of allowances that would decrease every single year.”

Democrats in the House of Representatives passed a cap-and-trade bill in 2010 that would have capped carbon emissions for businesses and forced emitters to buy credits for emissions from other businesses -- that’s the trade part -- but it never went anywhere in the Senate.

Many people think the most effective way to drastically cut carbon emissions would be to set a price on them -- essentially, to tax them, which O’Rourke said he opposes.

The International Monetary Fund recently suggested fossil fuel producers were getting more than $600 billion per year in subsides from the US government because they are not paying for the carbon they emit into the air. That’s part of a larger $5.2 trillion that the IMF paper suggested oil and gas companies were getting from governments worldwide.

Beto O'Rourke's climate crisis town hall just started, and he's taking questions from voters.

He's the ninth Democratic candidiate to take the stage in New York City tonight.