But we care about the planet, so should we really be shipping individual pairs of socks? Or should we just drive to the closest store?

There are lots of good arguments for buying local, but if you’re trying to reduce your impact on the climate, local isn’t always best. If you compare online shopping with driving to the store, in many cases online shopping can have a smaller carbon footprint: Trucks have to deliver goods to stores, just like they do to your house.

Problems start when we opt for speed: We don’t just want things delivered to our door, we want them delivered to our door right now. If we can get a pair of socks delivered in two days instead of five, we’re going to choose the faster option, especially if it’s free.

“Before, companies were able to consolidate, to optimize their distribution. Now, because some of them are offering really fast and rushed deliveries, that disintegrates the consolidation,” said Miguel Jaller, from the Institute for Transportation Studies at the University of California Davis. “Every individual is buying more and wanting those goods to be at their home really fast. That creates more vehicles, more traffic, and potentially more emissions.”

From a logistical perspective, the ability to get a pair of socks delivered to your door in less than a day is something of a triumph. But from a climate perspective, that speedy pair of socks takes us in completely the wrong direction, putting more of the most polluting vehicles on the road.

“If you look at passenger vehicles, they’re pretty darn clean at this point,” said Matt Barth, director of the Center for Environmental Research and Technology and a professor at UC Riverside. “Trucks are a different animal.”

Unlike passenger vehicles in the US, the focus of the bulk of emissions regulations to date, most trucks still run on diesel fuel, which produces larger amounts of air pollutants. Swapping clean car traffic for dirty truck traffic is a big step backward.

This doesn’t mean you have to throw out your holiday shopping list from climate guilt: There are things we can do right now to make online shopping cleaner. On the consumer side, we can opt for slower shipping times and try to consolidate our orders. From the company side, they could be doing a lot more to nudge us in that direction by providing incentives and simply alerting us to the fact that slower is greener — and it saves companies money, on top.

Delivery companies have been working on efficiency for decades, mostly to reduce costs. Since the 1970s, UPS has worked on ways to encourage drivers to take fewer left turns, reducing their emissions by around 100,000 metric tons of carbon dioxide every year. New technologies, from smart traffic lights that communicate with delivery vehicles to trucks that can drive in tight platoons to reduce wind drag and save on fuel, are also speeding our way in the coming years to help solve this problem.

Watch the video above with Jaller, Barth, and others working on new ways to get your socks to you quickly and guilt-free.

Learn more about groundbreaking work to solve the impact of transportation on climate change at climate.universityofcalifornia.edu.

Veerabhadran “Ram” Ramanathan, an atmospheric scientist at UC San Diego’s Scripps Institution of Oceanography, has been publishing on climate change for more than 40 years, dating back to the early 1970s when he discovered the greenhouse effect of CFCs. But his finest moment in scientific communication was not in a prestigious journal or a global climate conference.

In 2014, at a meeting of the Pontifical Academy of Sciences in Rome, Ramanathan learned that he was going to have a brief audience with Pope Francis. He quickly crafted a statement, tried to memorize it in Spanish (which he doesn’t speak), and headed to what he assumed would be a formal meeting in some ornate receiving room inside the basilica. Instead, as he was walking through the parking lot, he saw a familiar, pope-shaped man climb out of a Fiat and walk toward him.

“I completely panicked — it was a panic attack,” said Ramanathan of the moment he realized it was Pope Francis.

The Spanish words evaporated from his brain.

“I said, ‘Heck with it, I’m going to tell him in English,’” said Ramanathan.

Instead of getting into carbon dioxide emissions, sea level rise, and all the intricate details of climate science, he dove straight into the moral crisis that climate change presents.

“Most of the pollution is coming from the wealthiest 1 billion people, and the poorest 3 billion are going to suffer the consequences,” he told Pope Francis.

The pope not only listened but wanted to know what he could do to help.

“Since I was not prepared, I went to my heart to tell him, and I think without any exaggeration, those three minutes were my best scientific moments in my life. I could have blown this,” said Ramanathan.

Pope Francis included Ramanathan’s message in an address several days later, started tweeting about climate change, and in 2015 issued a 184-page encyclical focused on the environment and climate change. The pope has an audience of more than 1.2 billion Catholics around the world — an audience that trusts what he says.

The repeated failures of the scientific community to get the world to act on climate change are often chalked up to framing problems: If only the data were presented in a way that people understood, people would feel a sense of urgency and demand action. But reframing the argument isn’t a magic fix: Regardless of the topic, people actively seek out ways to reinforce what they already believe. The message matters, but it’s often the messenger that matters more.

This fact isn’t lost on Van Jones. Widely known as a CNN political commentator, Jones is also a founder of Green for All, a nonprofit that focuses on solutions for the people most directly affected by pollution and the effects of climate change.

“Low-income communities, communities of color — we get hit first and worst for everything bad with regard to the environment. We’ve got the cancer clusters, the asthma. We’ve got the incinerators right next to our playgrounds,” said Jones.

To his mind, it’s not just one pope or one Van Jones that’s needed — it’s going to take a chorus of voices to broaden the coalition to the point that there’s an effective climate movement in the US.

“You’ve got to have 20, 30, 40 million African Americans on your side. You’ve got to have 50 million Latinos on your side. And they’re not going to come in the same way that the other folks came in. They’re going to come in with a different set of agendas, a different way of talking about it, a different set of needs and priorities,” said Jones.

Watch the video above with Ram Ramanathan, Van Jones, a founder of the Tea Party movement, and others using trusted voices to bring more communities into the climate change fight.

Find out more ways that scientists and activists are finding new venues for talking about real climate change solutions at climate.universityofcalifornia.edu.

“When you look at the technology, and you ask yourself, how are we going to solve this problem of climate change, and how are we going to decarbonize? To not have nuclear energy on the table makes the job much harder,” said Per Peterson, a professor in UC Berkeley’s department of nuclear engineering.

The Fukushima Daiichi Nuclear Power Plant came online in the early ‘70s. Much has changed in the world of nuclear power plant design since then. Peterson is one of the researchers working on next-generation reactors, designed to be so safe that even Homer Simpson couldn’t cause a meltdown.

“In the last 20 or 30 years, we’ve developed different types of fuel, which, in fact, physically cannot melt,” said Peterson.

Peterson works with pebble-bed reactors, which use small spherical fuel “pebbles” where the radioactive material is encased in a ceramic shell that can withstand extremely high temperatures. In the case of a power outage or other problem, fuel pebbles empty into a holding tank where they don’t need water or other cooling systems like older reactor designs.

The kind of nuclear power plants you picture from The Simpsons or The China Syndrome, are mostly due to be decommissioned by midcentury. And they won’t be replaced in kind: New reactor designs eliminate the risk of meltdowns, operate at much lower pressure than older designs and use fuel more efficiently to reduce waste.

None of these advances can fully overcome nuclear energy’s biggest obstacle: fear. While many nuclear worries are overblown, Dan Kammen, also a professor in the department of nuclear engineering at UC Berkeley, is clear that nuclear power’s bad reputation has been well-earned.

“When you have spill of solar energy, what’s that called? It’s a sunny day, right? No one objects,” said Kammen. “Well, you have a spill of nuclear power, it’s not a sunny day.”

Perception of nuclear power plants has been deeply colored by the rare catastrophes — Fukushima, Three Mile Island, Chernobyl — so much so that people rarely consider how they compare with fossil fuel plants.

“Nuclear is massively safer than coal,” said Kammen. “I’d much rather have a nuclear plant nearby my home than a coal-fired power plant. When you look at the number of deaths on an immediate basis, even one of these horrible nuclear accidents or long-term from a coal plant, there really is no comparison.”

Not only is coal responsible for many more deaths and illnesses than nuclear energy, coal ash emits more radiation into the environment than nuclear plants. This isn’t hard to do: Living near a nuclear plant for a year exposes you to less radiation than you get from eating a single banana.

Even if we overcome the technical, logistical, and financial hurdles, can we ever get past our own fears?

Watch the video above with Per Peterson, Dan Kammen, and others working on how nuclear energy could play an important role in a carbon-free world.

Find out more about the latest thinking on clean energy and climate change solutions at climate.universityofcalifornia.edu.

Your dinner isn’t simply a delicious, innocent bystander. From the farm to your plate, there’s food waste at every step. And decomposing food isn’t just stinky; it releases potent greenhouse gases, mostly in the form of methane.

Even so, food waste should still be a relatively small issue, except that we needlessly waste food on such a massive scale that it adds up to a global problem. Just under 7 percent of greenhouse gas emissions come from food waste worldwide. To put that in perspective, if all the world’s food waste came together and formed a country, it would be the third-largest emitter of greenhouse gases, behind China and the US.

It might seem ridiculous to think of food waste as a country except as a thought experiment, but producing all of that unused food takes up real space — country-size space.

How much? According to a 2013 analysis by the United Nations’ Food and Agriculture Organization, the land devoted to producing wasted food would be the second-largest country in the world — smaller than Russia but considerably larger than Canada.

Imagine an area the size of Central America plus Mexico, plus the lower 48 states and a huge chunk of Canada, totally devoted to producing food we never even use.

There’s waste before food even leaves a farm; then food is shipped, stored, processed, sold in grocery stores, and served in restaurants or cooked at home, each step adding more to the food waste pile.

In the US, consumers are the biggest wasters. Nobody gets excited about throwing away food, so why are we doing it?

A lot of it comes down to little quirks of human psychology.

“One of the things we found in our research is that people are uncomfortable with white space when it comes to food,” said Dana Gunders, senior scientist at the Natural Resources Defense Council and author of The Waste-Free Kitchen Handbook. “We do not want to see empty space in our refrigerators, on our plates, in our grocery carts. In some subliminal way, we’re just filling everything.”

And the things we fill with food have gotten larger. Dinner plates have expanded by 36 percent on average since 1960, refrigerators have grown by roughly 15 percent since the 1970s, and our perception of “normal” portion sizes has grown along with them.

On top of this, in places where food is abundant, people have a talent for finding ways to rationalize throwing away perfectly good food, whether it’s because their pear is lightly blemished or because their soup has passed some arbitrary “best by” date.

Compared with other climate change challenges, problems like these are relatively easy to fix, and are currently the focus of a lot of attention from both startups and regulators. For starters, new, clearer food labels are coming in the US.

“What we’re seeing right now is a tremendous increase in attention and buzz on the topic of food waste, which is exciting,” said Gunders.

This buzz is leading to new, innovative food waste solutions that can help address both hunger and global warming at the same time.

Watch the video above featuring Dana Gunders and other researchers and entrepreneurs using both technology and human psychology to find solutions to food waste — and to get extra food onto the plates of people that really need it.

Find out more about new efforts to stop food waste and other climate change solutions at climate.universityofcalifornia.edu.

Our phones are the major culprit. On average, Americans get a new phone every two years. We’ll trust a 20-year-old plane to fly us across the country, and the average car on the road in the US is more than 11 years old — but a phone? Two years, and into the junk drawer of sadness it goes.

In truth, your phone’s demise isn’t the only part of its life we’d rather keep out of sight and out of mind. Candidly speaking, your phone has been around: picking up synthetic sapphire in China, lithium for a battery in South America, cobalt in Africa, plastic in the Middle East, processors in Korea, a display screen in Japan.

All that globetrotting comes with a hidden environmental cost. In fact, 80 percent of a smartphone’s climate impact happens before it ever reaches you.

According to Edward Humes, author of the book Door to Door: The Magnificent, Maddening, Mysterious World of Transportation, there’s 12,000 miles of travel just in the iPhone’s home button, and around 160,000 travel miles in a fully constructed phone. Multiply that by 2.6 billion smartphone users worldwide, and that’s a hefty chunk of greenhouse gas emissions — and a big area of opportunity for innovation.

The fact that parts and materials come from all over the world is mostly unavoidable; an easier target is reducing demand, for both new phones and raw materials. It would be a lot gentler on the planet if we didn’t swap out phones so often — so why do we?

Naturally, phone manufacturers want us all to buy the hottest new model, but for consumers, it’s more than just lust for a shiny new toy. It’s often a practical decision: After about two years, things start to go wrong. The usual suspect: the battery. Batteries have improved dramatically since the first smartphones were released, but they still lose their ability to hold charge over time — and you can’t just pop in a new one.

Batteries are the most obvious symptom of a larger problem: A smartphone is a sealed box that you can’t fix or upgrade. You can’t even open it without voiding your warranty. For some things, you can send it out for repair — but how long will you be left without a phone? The easiest fix to a broken phone or a dead battery is to simply get a new phone.

Julia Bluff of iFixit, a website that teaches people to fix almost anything themselves and advocates for consumers’ right to repair electronic devices, argues that while recycling phones is good, reuse is even better.

“Every single time you swap out a battery and you get another year or two of life, that’s one less phone that has to be manufactured,” Bluff said. “The longer that we can make these electronics last, the better off we are as a society.”

If we can’t reuse, then at least we can get those old phones out of the junk drawer and recycle them. Apple is getting in on the recycling action with a 29-armed robot named LIAM. LIAM can fully take apart an iPhone in 11 seconds, allowing components and raw materials to be repurposed. One LIAM can deconstruct roughly 1.2 million iPhones per year.

Watch the video above with Julia Bluff and others researchers and entrepreneurs working toward a cleaner future for smartphones, from a company making modular phones that are built to be upgraded to new long-life batteries that can be 3D-printed into any shape.

And who knows? Maybe, a decade from now, the forgotten residents of the junk drawer of sadness could emerge, repurposed for a bright new future.

Find out more efforts to make tech more sustainable and other climate change solutions at climate.universityofcalifornia.edu.

If that makes you sputter with disbelief, you’re not alone. Singer’s lifestyle provokes strong reactions: Some people think it’s great and want to learn how she does it, some insist that she’s a fake, and others respond like her way of life is somehow an attack on theirs.

“They feel like they’re under a microscope, like the fabric of what they believe in is being threatened,” she said.

Singer experienced this reaction close to home. In college, she tried to persuade her mom to switch to organic milk. It didn’t go well. Her mom felt like she was being backed into a corner, like Singer was criticizing her choices. So now when Singer talks to people about living a zero-waste life, she takes a different approach.

“Once people are presented [with] the topic in a way that breaks it down a little bit, they realize, oh, this isn’t so hard. This isn’t so isolating. This is something simple,” she said.

Singer herself didn’t get to zero waste overnight; it was a process. She learned to make her own toothpaste and realized how easy it was. Then she started taking reusable bags to the grocery store until it became routine. And she kept going like this until several pounds of trash a day turned into zero.

This may work on an individual level, but can we also do this at a scale that really makes a difference to a global problem like climate change?

The question of how to get society as a whole to make greener choices goes well beyond the issue of waste, but the worries are similar: Going green will be too hard and too expensive, and will require far too much sacrifice.

California has long enjoyed being a contradiction to these arguments, and Mary Nichols, chair of the California Air Resources Board, has had a front-row seat to the state’s climate change successes since the 1970s.

“Every time we approach the possibility of tightening up a regulation or setting a more aggressive goal, we hear some of the same concerns. ‘This time you’re going too far. This time it’s going to require actions that are going to be too expensive, too burdensome, that the public won’t support,’” she said.

This hasn’t been the case. Going green has hardly been terrible for California, even with some of the most stringent regulations and ambitious climate goals in the US.

“We have seen the economy overall in California outpace the national average, investments in green technologies have flowed to California in much greater numbers than any other place in the US, and whole new businesses have risen, grown up, or moved here,” said Nichols.

Watch the video above to see Singer, Nichols, and others explain how going green not only is not terrible but can be a benefit in many surprising ways.

Learn more painless climate change solutions at climate.universityofcalifornia.edu.

“Incredibly enough, it shows that the more certain the science becomes, the less concern we find in richer Western democracies,” he said. “How can it be that with increasing level of urgency and certainty in the science, people get less concerned?”

After further research, Stoknes, the author of What We Think About When We Try Not to Think About Global Warming, found some answers. He examined several hundred peer-reviewed social science studies and was able to isolate five main barriers that keep climate messages from engaging people, what he calls “the Five Ds”: Distance, Doom, Dissonance, Denial, and iDentity.

“I had to cheat a little bit with the last D — I lost one there — but it was the closest I could get,” he admitted.

Distance deals with the fact that climate change is presented as far away, in both time and space. When climate models talk of 2050 or 2100, it seems like eons from now. We may feel for polar bears on melting ice floes, but they have little bearing on our day-to-day lives.

To Stoknes, the dissonance problem might be an even bigger deal: What we actually do every day conflicts with what we know we should do.

“It makes us feel a little bit like hypocrites because I know it’s important, I shouldn’t do this, but yet we do it and we do it all the time, every day: eat meat, drive a car, go by plane,” he said.

For some, the uncomfortable feeling of dissonance makes them turn to denial, while others avoid the issue or feel powerless to make a difference.

While Stoknes concedes that individual actions alone can’t solve the climate problem, he doesn’t buy into the idea that we’re powerless.

“Individual actions, through their social ripple effects in the norms and values of people, will build the bottom-up support needed for the structural solutions. That is why individual action is important, not because I saved 11 kilograms of CO2 yesterday,” he said.

Change behaviors, change attitudes — but how do you get people to adopt new behaviors to begin with?

“In terms of behavioral change, we need two things,” said Magali Delmas, a professor at the Institute of Environment and Sustainability at UCLA and the Anderson School of Management. “We need first to increase awareness, and then second, we need to find the right motivations for people to change their behavior.”

She’s on the hunt for these motivations, looking for simple ways to make climate change personal.

In a recent study, Delmas and colleagues tested different messaging approaches with consumers to see what could cause them to lower their electricity usage. Some households were sent personalized emails with their monthly power bill telling them how they could save money, while others were told how their energy usage impacted the environment and children’s health.

Money proved to be a poor motivator: It had no effect. But linking pollution to rates of childhood asthma and cancer produced an 8 percent drop in energy use, and more than double that in households with kids.

Watch the video above with Delmas, Stoknes, and others who are finding practical ways to give us the collective kick in the pants we need to take action on climate change.

Find out more about how understanding human psychology can lead to climate change solutions at climate.universityofcalifornia.edu.