Also this week: We’re getting ready to live without plastic packaging. How hard could it be?

Hi, everybody!

As the world heats up, we’re seeing the effects in the oceans, which have absorbed about 90 percent of the heat trapped by excess greenhouse gases since midcentury. Our colleague Kendra Pierre-Louis has written two warm-ocean articles since our last newsletter.

One, with Nadja Popovich, looks at the increasing number of ocean heat waves and the damage they are doing to marine life. The other covers a study that says fish populations are declining as oceans warm, putting a major source of the world’s nutrition at risk.

That’s more evidence that climate change is on the march. But in Washington, President Trump is increasingly isolated in his denial of climate science, even among some senior Republicans. He is still getting his way on environmental issues in Congress, however, most recently with the confirmation of Andrew R. Wheeler, a former coal lobbyist, to head the Environmental Protection Agency.

But activists are pushing the Democratic leadership to take on warming as a major issue. That hasn’t worked in the past, said David Axelrod, who was chief strategist to President Barack Obama. “Climate change, to our frustration, was never an issue that rung a bell with voters, particularly in the throes of coming out of an economic crisis,” he said. “But now we’re a decade down the road, and the road is surrounded by floods and fires in a way that is becoming more and more visible.”

More visible, yes — but still open to a degree of rhetorical twisting. Brad Plumer explored the “weather wars,” in which scientists are increasingly comfortable explaining the links between extreme weather events and climate change, but every cold snap gets trumpeted by those who deny the scientific evidence for global warming.

Another recent study suggested that people may become inured to weather extremes over time. The researchers looked at billions of messages on social media and found that when weather extremes occurred repeatedly, people were less likely to comment about them online. Researchers suggested that this phenomenon might limit the public’s willingness to support action on global warming.

Well, you might ask, which is it? Will climate change shift the goal posts of normality, or will there be louder calls for action? The 2020 presidential race might help sort that out.

2020: The year of the climate candidates

It’s official: The 2020 Democratic presidential field is now awash with climate candidates.

Over the weekend, Gov. Jay Inslee of Washington announced that he would run, declaring himself the “only candidate who will make defeating climate change our nation’s No. 1 priority.”

In fact, every other Democratic presidential candidate has underlined his or her commitment to curbing planet-warming emissions — making the 2020 election much different from four years ago, when climate change was rarely mentioned.

“For far too long, climate change didn’t get nearly the attention that it deserved, either on the campaign trail or off, and that clearly has changed in a major way,” said Tiernan Sittenfeld, senior vice president for government affairs at the League of Conservation Voters.

In addition to Governor Inslee, Senators Cory Booker, Kirsten Gillibrand, Kamala Harris, Amy Klobuchar, Bernie Sanders and Elizabeth Warren have all identified climate change as a top campaign issue, as has John Hickenlooper, the former governor of Colorado. To varying degrees they have all also expressed support for the Green New Deal, a nonbinding congressional resolution that calls for a 10-year mobilization to dramatically reduce the burning of fossil fuels in the United States.

Some political scientists have suggested that extreme weather has made the issue of climate change more immediate for voters. Others say that President Trump’s denial of climate science has actually highlighted the problem. And the Green New Deal and one of its main sponsors, Representative Alexandria Ocasio-Cortez of New York, have sparked new enthusiasm among Democratic voters.

Thomas J. Pyle, the president of the Institute for Energy Research, a think tank that supports fossil fuels, said that, with so many Democratic candidates talking about climate, it would be harder for a candidate like Governor Inslee to stand out.

“If he ran in the last go-round he could probably distinguish himself as Mr. Green Jeans, but he’s just going to be one more voice in the choir promoting these extreme ideas,” Mr. Pyle said.

One thing that’s been missing from the early campaign discourse, however, is what the candidates would actually do. For all the talk of a Green New Deal, there has been little support for its main policy prescription: a price on carbon.

Robert Shrum, a professor of politics at the University of Southern California and a longtime adviser to Democratic candidates, said he was not concerned by the lack of specifics at this point.

“There will be a lot of push in the Democratic primaries to pin people down on specific positions, but right now it’s early days,” Mr. Shrum said. “What’s clear is that the climate issue really matters.”

One thing you can do: Try living a plastic-free life

When it comes to leading a sustainable lifestyle, I think I’m doing an O.K. job. But I have to admit that I waste a lot of plastic.

I just took a quick look around my kitchen and found about 20 food products in nonrecyclable plastic packaging, including baked tofu, smoked salmon, goat cheese, spices, cereals and chocolate chip cookies.

In a matter of days, all that plastic will end up in the trash can, and it will later be part of the roughly 35 million tons of plastic that waste disposal services collect every year in the United States. Though some of these plastics will be recycled and reused as something else, chances are that they’ll eventually wind up in a landfill or in the environment anyway.

According to a United Nations estimate, by 2050, there will be roughly12 billion metric tons of plastic litter in landfills or the environment worldwide, and it will stay there for hundreds of years because plastics decompose so slowly.

Since most food products and toiletries come in disposable plastic packaging, is it possible to avoid using plastic in this way?

Sophie Bortolussi, a dancer and choreographer in New York City, has been trying to do just that for about a year — “for the common good,” she said.

Finding staples like bread, yogurt, coffee and pasta in reusable or biodegradable packaging was easy, but nowadays she very rarely buys sparkling water, olives, berries and cookies.

She shops in food co-ops, farmers’ markets and old-school grocery stores that sell products in bulk. “I’ve created new habits around my plastic-free lifestyle by learning what I can buy and where,” she said.

She’s far from the only person trying to go “zero waste.” Many converts chronicle their waste-free lifestyles in blogs and YouTube videos, and some pioneers, like Lauren Singer, have started businesses that sell package-free products.

Sabrina Katz, 24, says she was once a “shopaholic,” but in college she came across Ms. Singer’s blog Trash Is For Tossers, which inspired her to go plastic-free.

It wasn’t easy — she had to give up chips, many tofu products, granola bars and Oreos. But three and a half years later, she still buys most of her groceries at stores that sell in bulk and takes them home in Mason jars.

“The foods that I find in bulk are really healthy foods — things like beans, whole grains, oats, pasta and fresh fruits and vegetables,” she said. “That means that I cook most of what I eat, which is a blessing and a curse.”

Like Ms. Bortolussi and Ms. Katz, I want to see if I can reduce the amount of plastic I waste. Over the next week, I’ll adopt a lifestyle free of plastic packaging. I think it will be “a blessing and a curse.”

Next week, I’ll let you know how the experiment went. In the meantime, we’d love to hear from you. Do you have tips on avoiding plastic packaging or plastics in other parts of your life?