Live commentary: How to solve the climate crisis

8:54 p.m. ET, September 4, 2019

The single most important goal of the candidates' climate plan

The most urgent climate challenge of the next two years is to get Donald Trump out of the White House. Unless that happens, there is no way to restore sanity to US climate policy. Four more years of Trump is unthinkable.

Therefore the most important climate plan is not the most eye-wateringly dramatic version of the Green New Deal, but the one that – as part of an overall winning strategy – stands the best chance of persuading the widest spectrum of American voters possible, and across political divides.

It won’t be easy, because climate change has become part of the culture wars, and many right-wing voters see climate denialism as a core part of their political identity.

For this reason it is a mistake for Democrats to go too far to the left with their Green New Deal and climate wish lists. What matters is reducing emissions to zero as quickly as possible, nothing else.

One way for candidates to show they are serious is to endorse the current grassroots campaign to keep nuclear power plants open across the US as alternatives to fracked gas.

Yet Buttigieg, Castro and Sanders, for example, all oppose nuclear, for no good reason. Nuclear is still by far the largest-source of emissions-free electricity in the US. It is also largely supported by Republican voters and politicians.

A climate plan that phases out the nation’s largest source of emissions-free power indicates more clearly than anything that a candidate values political tribalism over the urgency of the climate crisis.

The starkness of the two parties’ divide is illustrated by the mere fact of this CNN Climate Crisis Town Hall. The Democrats are debating sensible and thoughtful ways forward to tackle the climate crisis.

The Republicans are persisting in outright denial of the basics of climate science, and their leader, the President, is calling climate change a hoax and trying to keep the US hooked on coal--after pulling the nation out of the only international climate treaty that matters, the Paris Agreement.

If we continue with the politics of Trump, the climate crisis will not be solved, and the world will tip into a spiral of rapid global heating, bringing temperatures that this planet has not experienced for millions of years, endangering human civilization and causing a mass extinction of other life.

Nothing else matters. Whatever climate plan has the best chance of defeating Trump is the one to go for.

Mark Lynas is the author of several books on climate change. He is currently writing an updated version of Six Degrees, due to be published next year. Twitter @mark_lynas

7:54 p.m. ET, September 4, 2019

Harris didn't have all the answers -- but was overall impressive

Kamala Harris was impressive. Making a lot of references to her record in California -- which has great environmental policies and has tackled climate and other environmental issues more effectively than any other state -- Harris was very self-assured. Her California record is a big plus - though a lot of distinctive California policies predate her. 

But she waffled on some issues. Nuclear was one. Should we replace nuclear power stations at the ends of their lives by more of the same, or by renewables?

This is a complex question and Senator Harris didn’t seem to have thought it through. She talked mainly about the disposal of nuclear waste and Yucca Mountain – a big issue but not central to the choice.

And she said she’d leave it to the states.  But we need action at the federal level if we are to develop and implement new nuclear technologies. She would ban fracking and the production of oil and gas on federal lands – I agree, but this is controversial and perhaps not necessary. If we can reduce the use of oil and gas by promoting new technologies, this will automatically reduce demand for oil and gas and so its production.

Overall she seemed very emphatic about the importance of climate.

Geoffrey Heal, the Donald C. Waite III Professor of Social Enterprise and a Chazen Senior Scholar at Columbia Business School, is the author of "Endangered Economies -- How the Neglect of Nature Threatens Our Prosperity."

10:55 p.m. ET, September 4, 2019

Kamala Harris short on specifics

Kamala Harris seems to be confused. She dodged the opening question—would you declare a climate crisis?—by saying she would declare a drinking water crisis. She segued to the Montreal Protocol, but that deals with the ozone hole!

On the big policy questions—like carbon pricing—she seems lacking in specifics and repeatedly resorts to the slogan, “leaders have to lead.” Sure, but how exactly? She talked about a lot of small-bore issues like plastic bags, drinking straws, and cheeseburgers. Not eating cheeseburgers might be a good idea, but it is not a policy. 

Harris also talked at some length about climate change denial, in part in response to a question about its parallels with tobacco harm denial. My colleague Erik Conway and I literally wrote the book on that parallel, but I don’t think that is the central issue now. Polls all show that the American people are on board about climate change; our central challenge is to implement the policies that will accelerate the renewable energy transition. 

How do we do that? She had very little to say. I’d say her heart is in the right place, but both Castro and Yang are in front of her on the specifics of the issue.

Naomi Oreskes is Professor of the History of Science at Harvard University and the author of the new book Why Trust Science?

9:22 p.m. ET, September 4, 2019

What the candidates aren't discussing

There’s a fine line that the candidates have to walk. On the one hand, so much more needs to be done to fight climate change -- and so much more quickly. We need to step up our efforts, and the candidates are right to focus on this. On the other hand, there are policy successes that the candidates should cite and build on. So far, we haven’t had enough discussion of the policies that have driven technological innovation.

Of course, this is not to say there has been no discussion of innovation and smart policies. Sen. Kamala Harris mentioned the process of innovation in passing, and businessman Andrew Yang discussed the importance of pushing industrial efforts toward more low-carbon innovation.

But we’re still missing some of the most inspirational evidence of recent progress in batteries, wind power, electric vehicles and solar energy. In the case of solar energy, the costs of solar panels dropped 99% over four decades. This drop in costs was driven by government policy, with an estimated 60% of the cost decline driven by market-expansion policies around the world to grow solar energy, and 30% from global government support for research and development.

It’s easy for people to feel discouraged when talking about the climate change challenge. The problem seems enormous, and many feel their individual decisions and votes don’t matter. But recent history shows something different -- with real and tangible policy successes in driving technological innovation. Candidates should cite this evidence. And the American people should recognize how powerful their votes can be.

Jessika Trancik is an Associate Professor in Energy Systems at MIT’s Institute for Data, Systems, and Society.

9:11 p.m. ET, September 4, 2019

Yang hits the ball out of the park

Andrew Yang just hit the ball out of the park. He moved the debate right where it needs to be: into the economic and politics of climate change. 

In a few short minutes, he raised three crucial points that economists have been trying for years to get front and center in our debate.

1.) The GDP is a terrible measure of well-being and needs to be replaced by something that takes into account health and environmental sustainability.

2.) We currently subsidize the fossil fuel industry to the tune of hundreds of billions of dollars per year. (Most Americans think that renewables are heavily subsidized, when, in fact, permanent tax expenditures that subsidize fossil fuels exceed renewables by a 7-1 margin)

3.) Jobs versus the environment is a false dichotomy. He is totally right about that. More than that, it is a pernicious myth. I’ve never understood why Democrats don’t do more to reject it. Good for Yang for calling this out in no uncertain terms.

I don’t know if this man is qualified to be President, but he’s on track on this issue.

Naomi Oreskes is Professor of the History of Science at Harvard University and the author of the new book Why Trust Science?

6:10 p.m. ET, September 4, 2019

The key question tonight

The fundamental question tonight -- how will Democratic presidential hopefuls separate themselves on climate change?

Democrats concur that rejoining the Paris Climate Agreement is important. But telling voters in my hometown of Denmark, South Carolina, about plans to rejoin the Paris Climate Accord does not make clear how their lives and communities will be directly impacted. And Democrats cannot afford to lose sight of what climate change means for marginalized Americans, particularly rural populations and communities of color. 

Railing against fossil fuel executives might be therapeutic, but what does transition look like for communities whose livelihoods rely on those jobs? What resources will be directed to low- and moderate-income communities that are hardest hit by extreme weather? And how will candidates ensure that post-recovery communities are still affordable and not catalysts for gentrification?

Additionally, the Senate map still presents an uphill battle, even if Democrats win the White House in 2020. As a result, any sound climate agenda that is introduced will likely be in jeopardy because of Senate Republicans. While there is value in proposing ambitious legislative measures, we also need a Plan B. 

Simply put, how will the next Democratic president's executive authority effectively move the needle on climate change and build on the environmental justice strides made during the Obama administration? Families deserve answers to this question.

Lastly, it is hard to argue that Washington Gov. Jay Inslee’s focus on climate change has not shaped the Democratic primary. Tonight’s town hall is a testament to his leadership on this matter, and we will sorely miss his perspective. 

Bakari Sellers is a former Democratic member of the South Carolina House of Representatives and a CNN commentator.

6:07 p.m. ET, September 4, 2019

Castro's heart-stopping idea

Secretary Castro wants to rejoin the Paris Accord (what Democrat doesn’t?) and follow it with a series of executive orders. But executive orders are fragile. Unless we can build a coalition—in Congress, or on the state and federal level—any action taken by the White House is unlikely to prove transient and ineffective.

Castro should do more to emphasize the jobs that are being created in the clean energy sector—far more than in fossil fuels—and that clean energy is cheaper than dirty energy. These economic benefits offer a basis for building a new, profitable, clean energy system.

The heart-stopper of Castro's segment was when he said he wants to see that “more people are protected by national flood insurance” by subsidizing it. That would be a mistake. Flood insurance encourages people to live in flood zones that should never have been populated in the first place, and are now more vulnerable than ever. It’s sad, but the reality is that climate adaptation will necessarily involve relocating some Americans out of high-risk flood zones. I would rather he had suggested paying for necessary relocation out of his carbon pollution fee.  

The gaffe of his segment was his promise to make America “carbon-free.” All life is based on carbon; we can’t be carbon-free! What he means is carbon-emissions-free, but that is harder to say.

Naomi Oreskes is Professor of the History of Science at Harvard University and the author of the new book Why Trust Science?

4:37 p.m. ET, September 4, 2019

Emma Thompson: Everything depends on what we do now

All over the world life forms are experiencing weather that attacks rather than sustains.

Unseasonal heat that kills, rain that instead of sweetening, inundates and destroys, hurricanes that devastate.

This is climate change.

We are in it. It is all around us and set to get worse.

Everything depends on what we do now.

To read more from Emma Thompson's op-ed, click here.

Emma Thompson is a writer and actor from the UK.  

4:37 p.m. ET, September 4, 2019

Those who come after us will either curse us -- or thank us

Climate change isn't what I'd call urgent. Not any more. The time for urgency has passed. Our government and the rest of the world largely ignored the red lights and warning bells. It's now much bigger, and much worse, than urgent.

Heat waves, wildfires and monster storms are killing people outright. Unstable weather is threatening the global food supply. So is seawater acidification, which is destroying coral reefs that support the ocean food chain.

Rising seas threaten to inundate all low-lying seacoasts and islands.

Climate change so dominates news about the environment that many of us seem to have forgotten that we have a ton of other major problems not directly linked to a warming planet. Shrinking wild lands, polluted air, poisoned waters, exhausted farmlands and depleting irrigation and drinking wells, overfished seas, species going extinct, clearcutting for more farms and more wood, a plasticizing ocean, mercury in seafood. It goes on.

To read more from Carl Safina's op-ed, click here.

Carl Safina's most recent book is "Beyond Words: What Animals Think and Feel." A MacArthur Fellow, he holds the Endowed Chair for Nature and Humanity at Stony Brook University and is founder of the not-for-profit Safina Center.