By Stephen Battersby for the Proceedings of the National Academy of Sciences.
Broadcast version by Kathryn Carley for Commonwealth News Service, reporting for the Pulitzer Center-Public News Service Collaboration.
As a phrase and as a promise, net zero has been a great success. Hundreds of countries have pledged to reduce their net greenhouse gas emissions to zero by around the middle of this century. So, too, have thousands of regions, cities, and companies. Net zero has become a beacon of hope, guiding us to climate safety.
But look closely, and the beacon becomes a little blurry. Some scientists argue that net zero might lead us to rely too heavily on technologies that capture CO2 from the air. That could bring dangerous delays and unwelcome side effects, and give fossil fuel producers leeway to keep pumping and polluting. And its allure may be obscuring our need to look beyond net zero to a more ambitious goal-a world of net-negative emissions.
Some climate scientists have ideas about how we could refine net zero to make it a more focused and effective target. Others say it should only be one part of a new climate narrative. "We don't think enough about net zero, what it means, and if it's the right goal," says environmental social scientist Holly Jean Buck, of the University at Buffalo in New York.
With the fate of the planet riding on the outcome, it's vital that governments and institutions are not led astray by their climate beacon-so the debate over net zero is more urgent than ever.
The Root of Zero
The idea of net zero is firmly based on climate science. In the 2000s, scientists worked out that if we stop pouring CO2 into the atmosphere, global average temperatures should roughly stabilize. That is because two effects of Earth's oceans happen to cancel out. Today, the atmosphere is kept relatively cool by the oceans. As seawater slowly warms, we lose that cooling effect, so if emissions fall to zero, we might expect the atmosphere to carry on warming for a few decades-a phenomenon known as thermal inertia. But the oceans also keep absorbing CO2, which should roughly balance the thermal inertia and keep temperatures steady.
Net zero took off in 2018, driven by the United Nations report "Global Warming of 1.5 °C." Three years earlier, the Paris Agreement had set out a goal to limit warming to well below 2 °C above pre-industrial levels and pursue efforts to limit it to 1.5 °C. The new report laid out how the world might try to hit the more ambitious end of that goal, based on models that combine climate and economic activity. It concluded that to avoid warming of more than 1.5 °C, we would not only have to cut emissions deeply, but also remove a lot of CO2 from the atmosphere. Such removal could balance any stubborn, ongoing sources of greenhouse gases, known as residual emissions. These might include CO2 from concrete manufacture, for example, or nitrous oxide from fertilizers. So instead of absolute zero emissions, the new goal aimed for net zero, which allows some residuals to be balanced by removal.
This was only possible because technologies that remove CO2 from the air had become feasible. "Targets through the years have tended to reflect the practicality at the time of reducing emissions," says climate ecologist Stephen Pacala at Princeton University in New Jersey. "When you could envision a practical path to zero net emissions without leaving the world in poverty-all of a sudden, humanity jumped on net zero as a target."
It has undoubtedly had a galvanizing effect. "Before this, few companies had climate targets at all," says Sam Fankhauser, a climate economist at the University of Oxford in the UK. "So this is a step in the right direction."
But that shouldn't be the end of the story. "Net zero comes from the science, so it's subject to change as we learn more," says climate economist Sabine Fuss at the Mercator Research Institute on Global Commons and Climate Change in Berlin, who was a lead author on the "Global Warming of 1.5 °C" report. Climate scientists agree that the concept holds several crucial ambiguities that need to be resolved.
Zero Sum
For a start, what is the best balance between cutting emissions and removing CO2? That depends on which emission sources will be too difficult to cut. But when Buck and her colleagues analyzed 50 national long-term climate strategies, they found that countries are inconsistent in how they consider residual emissions. "The risk is that governments put things that are expensive or politically inconvenient to abate into the 'residual box,'" the paper states. That makes it hard to know how much CO2 removal we need.
According to these strategies, the average residual emissions in developed countries will be 18% of current total emissions at the time of net zero. Extended to the whole world, that would imply annual removals of at least 12 billion tonnes of CO2.
Natural solutions, such as planting forests, can't come close to reaching this quantity on their own-and in a warming world, they will be increasingly vulnerable to fire, disease, and chain saws. So the assumption is that we will use a range of novel removal methods: using machines to suck CO2 directly from the atmosphere, for example, or burning biomass to generate energy while capturing and storing the CO2 emitted.
Most of these technologies operate at small scales today, collectively removing only about two million tonnes of CO2 per year. For now, most of them are expensive to operate. Some need a lot more research and development and may yet prove difficult to scale up. That's the first problem with asking too much of carbon removal: It might not have the capacity to meet such high demand, and then we would fail to hit net zero.
The second problem is unwanted side effects. Deployed at large scale, biomass-based CO2 removal could compete for land with agriculture or with rich ecosystems, which could push up global food prices or harm biodiversity. Other approaches are also likely to have snags, especially if stretched too far. Direct air capture requires a lot of energy, which must come from a very-low-carbon source not to be counterproductive. Enhanced weathering, which involves grinding certain types of rock to speed natural CO2-absorbing chemical reactions, could create air pollution.
Without defining the levels of reductions and removals that lead to net zero, there's no clear imperative for each country or company to cut its emissions to the bone. Instead, they might hope to pay others to remove lots of CO2 on their behalf. "Everyone thinks they will buy negative emissions from someone else," says climate scientist Bas van Ruijven at the International Institute for Advanced Systems Analysis in Laxenburg, Austria.
Worse, it seems increasingly likely that CO2 removal will have to go beyond merely balancing residuals. "Now it looks like we will need net negative to meet the Paris goal," says Fuss. That means removing more CO2 from the atmosphere than we put in. Researchers in the international ENGAGE project have developed models that include a range of sociopolitical constraints, such as the ability of governments to enforce climate legislation. These models project that climate warming will overshoot the 1.5 °C target by 2050. Reversing that overshoot would require several hundred gigatonnes of CO2 removal during this century. "So you cannot have an enormous amount of residual emission, as then you need an even more enormous amount of carbon removal," says van Ruijven, who is a member of the ENGAGE project.
It may be wise to go further and try to repair some of the damage we have done, dialing down global temperatures closer to pre-industrial levels and curbing the ocean acidification caused by absorbed CO2. That would, of course, require even more removals. Despite this, companies and countries are not yet planning to reach net negative.
In some quarters, net zero is seen as a final goal. This could leave the door open for fossil-fuel production to continue at high levels and for new infrastructure that could commit us to burning those fuels for decades to come. "We haven't focused enough on the phaseout of fossil fuels," says Buck. "If we only focus on emission at the point of combustion, then we are missing half the picture." The 2023 UN Climate Change Conference (known as COP28) alluded to this problem, calling for "transitioning away from fossil fuels in energy systems." But, this falls far short of a phaseout. "It is promising that they said something, but it could have been stronger," says Buck. "What you need is a plan and a lot of resources committed to phaseout."
Zero Clarity
Net zero holds a host of other ambiguities. "Today, everybody has their own idea of what net zero means," says Fuss. "So we should take a step back and refine the concept. It is really important to get all these things straight, so we are not fooling ourselves."
For example, it's unclear whether net zero should include climate feedback effects, such as CO
2 emitted by thawing permafrost. These could require vastly more removals to prevent temperatures from rising.
Nor does the target emphasize urgency. If governments are aiming for net zero in 2050, they might feel free to kick their heels for a while. But many mitigation measures will need decades to scale up, so "it's vital to reduce emission as much as possible in the short-term," says Fuss. "You don't break something just to then repair it."
Net zero doesn't yet specify the durability of removals, either. Today's emissions will linger for centuries, so they can't simply be balanced by a form of removal that is likely to last only years or even decades. As Fankhauser et al. write: "Achieving net zero through an unsustainable combination of fossil-fuel emissions and short-term removals is ultimately pointless."
The sum should also explicitly include any knock-on effects. For example, planting forests at high latitudes can be counterproductive because they create a darker landscape that absorbs more solar heat, melting local ice and snow.
Then there is the question of whether to include other greenhouse gases, such as methane, in the net-zero sum. Methane has a much shorter lifetime in the atmosphere, so attempting to cancel out methane emissions with CO
2 removal would tend to mean more warming in the short term, and less in the long run. That could be good or bad, depending on whether it takes us past climate tipping points.
Zooming in on Zero
How can we do better? The first thing is to decide what should be classed as a residual. "We should make sure that residual emissions are truly hard to abate," says Buck. Voluntary codes are starting to address that, including the net-zero corporate standard launched by the Science Based Targets initiative, which calls for residuals to be only 5-10% of a company's current emissions.
To get removals moving, Fuss thinks that we need higher prices on carbon emissions. "If we are asking people to remove, we are asking them to perform a public service," she says, "so we should be compensating them for extracting each tonne of CO
2."
Carbon pricing could also curb fossil fuel production. Pacala led a 2023 National Academies report on accelerating decarbonization, which, among other things, recommended an economy-wide carbon tax in the United States. He says that the 2022 Inflation Reduction Act (the nation's main policy tool for moving toward net zero) omitted any such tax in order to gain political traction.
Assuming that carbon removals can scale up fast enough, it will be vital to prove how much CO
2 they are removing, through monitoring, reporting, and verification (MRV) systems. That could be challenging. "MRV is hard enough with forests, where we already have decades of experience," says Buck. "With novel techniques, it's a big challenge, and I'm not sure it's solvable on a timescale of 20 years or so." But there are some promising signs. In November 2023, the European Parliament voted to adopt a new certification scheme for removals, aiming to boost their credibility and scale. Meanwhile, advances in remote sensing and machine learning could make MRV more achievable.
As well as trying to redefine net zero, perhaps nations and societies also need to take a step back and think more broadly about what to strive for. Buck thinks that net zero should become just one among a set of targets, including reductions in fossil-fuel production and enhancing the capacity of countries to implement the clean-energy transition. She also considers the term to be fundamentally unsatisfying, a piece of accountancy that is not compelling to most people. Perhaps the world needs a more inspiring climate narrative that comes not just from scientists, but also other groups. "We need to evolve broader languages," Buck says, "and make more effort to understand what would encourage people to change their lifestyles and consumption."
Fankhauser, meanwhile, cautions against focusing on climate impacts alone. "The risk is that we maximize natural systems for carbon uptake but compromise biodiversity and other ecosystem services," he says. "We need a holistic point of view."
Climate solutions should also avoid dumping pollution or costs disproportionately on disadvantaged communities. This isn't just a moral matter. "People are not going to go along with these changes unless they see benefits in their own lives," says Pacala, who points to the plight of coal miners in the United States and other workers whose jobs may be threatened by the energy transformation. "We have to manage the jobs of legacy workers, who were previously thrown under the bus," he says.
At the moment, there is no pithy phrase to sum up these diverse aims. "Net zero is powerful because it is two words," says Fankhauser. Adding more detail could spoil that rhetorical impact. Low-residual, urgent, all-greenhouse-gas net zero, aligned with biodiversity and poverty reduction-it hardly trips off the tongue. For now, at least, researchers and policymakers may have to stick with those two words, while carefully contemplating all the things that add up to zero.
Stephen Battersby wrote this article for the Proceedings of the National Academy of Sciences.
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By María Ramos Pacheco for The Dallas Morning News.
Broadcast version by Freda Ross for Texas News Service reporting for the Solutions Journalism Network-Public News Service Collaboration
Anamelia Jaramillo has lived in Jubilee Park for almost 20 years and is concerned about the heat getting worse every summer.
She fears her air conditioning system failing because her husband has diabetes and can be vulnerable to extreme heat.
“I wish we didn’t have to have the A/C running all day long, but it is impossible to survive in the summer without it,” said Jaramillo, 54, after attending a Zumba class at Jubilee Park on Nov. 11.
In 2023, more than 20 people died in Dallas and Tarrant counties from heat-related illnesses as Texas saw record heat waves and triple-digit temperatures, according to the counties’ medical examiners. The lack of trees and green spaces, such as community gardens and parks, in an urban area contributes significantly to the “urban heat island effect,” as buildings, roads and other hard surfaces absorb and retain more heat.
Dallas’ District 7, where most of the neighborhoods participating in the South Dallas Greening Initiative are located, was ranked the third-highest priority for tree canopy, according to the Dallas Tree Equity Mapping Report published in 2022 by the Texas Trees Foundation.
Districts 4 and 6 ranked as the first and second highest priority for tree canopy, and the organization has been deploying some of their programs to plant more trees in these areas. Early this year, the Texas Trees Foundation released its plan to tackle the lack of trees in the Southwestern Medical District as part of its initiatives to combat the urban heat island effect.
Texas Trees, through the South Dallas Greening Initiative, also is working in the Jubilee neighborhood to address the area’s lack of trees to combat the extreme heat affecting residents’ health and quality of life. The nonprofit is providing thousands of trees to the almost 50,000 residents of Fair Park, Mill City, Queen City, Wheatley Place and adjacent neighborhoods over five years. Jubilee Park is just below Interstate 30 and north of Fair Park.
Chandler Stephens’ father, Calvin Stephens, has owned two vacant lots in South Dallas since the 1980s. The younger Stephens has been talking with Texas Trees about working together on his vision to create a community garden.
Stephens dreams of having a green space in every corner of South Dallas to improve residents’ quality of life.
“I can see [the initiative] as something that will prolong the community’s livelihood. Not only with addressing the urban heat island issue but just by providing greenery,” Stephens said. “Plants and our health is so linked to the health of the earth and the planet.”
The Dallas Comprehensive Environmental and Climate Action Plan established protocols for adapting to climate change challenges in 2020. It states that Dallas needs approximately 735,000 trees to reach a goal of 37% tree canopy cover and, specifically, mitigate the urban heat island effect.
Since its founding in 1982, Texas Trees has planted an estimated 1.5 million trees across the Dallas-Fort Worth region. In 2023, the Dallas-based nonprofit secured a $15 million grant from the Reduction Act through the U.S. Forest Service’s Urban and Community Forestry program for the South Dallas Greening Initiative.
The project, however, is part of a long-term solution to extreme heat, and many of Jubilee’s residents want to see more.
“I am in favor of the initiative and for them to plant more trees in the area, but we also need help with how to pay the electricity bills,” Jaramillo said.
In any community, including South Dallas, trees may not be at the top of each resident’s list of the needs they see for their community, said Elissa Izmailyan, chief strategy and operations officer with Texas Trees.
“We are showing up with a commitment to help and the ability to offer trees and urban forestry education but realize that we’re entering a landscape where there are a lot of other needs and priorities,” Izmailyan said.
“So first, we need to be sensitive to that broad range of priorities and capacities. Second, we need to think about how our offering intersects with other needs in a way that’s additive.”
The project will have several components beyond planting trees in the community, Izmailyan said.
The first phase has been to reach out to the community and work with nonprofits and organizations in South Dallas to establish a trusting relationship and understand the community’s needs and wants.
That’s where partnerships with local organizations come into play, as well as involvement with community leaders.
The Jubilee Park and Community Center is a nonprofit that works to restore equity and resources for the 3,000 residents of the Jubilee neighborhood. The community center has been around for almost 30 years and offers education, health, food access and after-school programs.
Emily Plauche, Texas Trees’ community greening manager, said the initiative includes an educational component that teaches residents about trees, their benefits, how to care for them, green jobs and other measures that can be taken to combat extreme heat.
“So there’s always going to be other needs or things that arise, too, and we can’t necessarily, with our money, purchase that. But we can help advocate and get the city involved and bring other people to the table who have some of these potential solutions,” Plauche said. “We are deeply committed to the well-being of the community.”
Texas Trees will work with some of the area’s schools to boost green spaces and tree planting on the campuses. The organization already runs a program across the city focusing on schools needing more canopy.
Marissa Castro Mikoy, president and chief executive officer at Jubilee Park, said that over the years Texas Trees has helped plant over 150 trees on their campus, and they can see the benefits to the community, from providing shade to beautifying the park.
Benefits of trees
In April, Dallas shared findings from a study that identified at least 10 neighborhoods as urban heat island spots. Some of these spots have less green space, and the temperature is 10 degrees hotter than in other parts of the city.
Trees can help reduce the urban heat island effect and improve people’s and the environment’s health in several ways.
They provide shade and block incoming solar radiation, lowering temperatures by several degrees. They also release water vapor, which can help cool temperatures. According to the Environmental Protection Agency, trees sequester carbon from the atmosphere in their wood and roots, absorb gases and provide a place for harmful air particles to land.
At the same time, according to the U.S. Forest Service, trees provide mental health benefits such as stress reduction, improved mood and a sense of well-being due to increased exposure to nature.
Cities across the country and the world have documented the long-term effects of planting trees strategically in urban areas.
In Chicago, according to studies, neighborhoods with higher tree canopy cover have experienced temperature reductions of up to 4.6 F to 6.8 F compared to areas with little or no tree canopy.
Similarly, in Medellin, Colombia, temperatures fell by 3.6 F in the first three years of their program installing green corridors, and officials expect a further decrease of 7.2 F to 9 F over the next few decades, even taking into account climate change, the Secretary of Environment of Medellin reported.
Limitations
Trees are one solution that can help residents in South Dallas combat extreme heat, but Castro Mikoy said the initiative needs to be combined with solutions to the area’s other problems.
Displacement, making ends meet and food insecurity are some issues facing South Dallas residents that make heat waves even more damaging for them.
Silvia Herrera, 48, a Jubilee resident, avoids turning on lights and household appliances during the day in the summer to keep her home cooler and reduce her electricity bills. She said her bill is around $500 in the peak summer months.
“You have to make decisions such as when you turn on the A/C and what things to avoid to spend less energy so the bill [electricity] is not too high because then I can’t pay for it,” Herrera said.
Planting trees and having the ecosystem to purchase, transport and maintain them can also be expensive. The South Dallas Greening Initiative was able to come to life because of the grant Texas Trees secured. Not all cities or organizations can afford this type of solution, which is a limitation to replicating this program everywhere.
Community First
Through the five-year plan, Brittani Hite, strategic director of Ethos Equity Consulting, which is working with Texas Trees on the initiative, said there should be no surprises for the residents.
The project is for the community and by the community, said Hite.
“We understand that the solutions are already within the community,” Hite said. “South Dallas residents know what they want. They know what they need, but because of environmental and ultimately systemic racism, unfortunately, we lack green spaces, trees and other basic necessities in our city’s Black and brown neighborhoods.”
From Hite’s perspective, the conversations among the Jubilee moms after Zumba classes to Stephen’s dream of having community gardens that work with the wants and needs of the South Dallas community, will have an impact on finding the right solution.
María Ramos Pacheco wrote this article for The Dallas Morning News.
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By Ethan Brown for The Sweaty Penguin.
Broadcast version by Shanteya Hudson for Alabama News Service reporting for the Solutions Journalism Network-Public News Service Collaboration
A 2023 Pew Research survey found only 27% of U.S. adults feel individual actions can help "a lot" to reduce the effects of climate change. But according to panelists at a Tuesday webinar from ClimateVoice and WorkforClimate, there's a solution - advocacy in the workplace.
"A lot of people understand that if they can get a hold of their employer's resources, they can have an outsize impact on climate change in a way that you will never be able to do as an individual voter or consumer," said Drew Wilkinson, Founder of Climate Leadership Collective.
Prior to founding his own company, Wilkinson was a paralegal at Microsoft. In 2018, two years into his tenure, he emailed The Ocean Cleanup to propose a collaboration at Microsoft's Global Hackathon to find solutions for ocean plastic pollution. At that point, The Ocean Cleanup had built technology to remove plastics from rivers and deployed it in Indonesia and Malaysia, but could not yet identify whether collected waste was actually plastic, or other debris such as sticks and leaves. Through Wilkinson's Hackathon project, participants developed a machine learning model to perform this task, successfully identifying over 30,000 ocean photos.
That same year, Wilkinson and a coworker launched the first employee sustainability community at Microsoft. The group grew rapidly, reaching 10,000 members and 37 local chapters in 2023, and playing a central role in Microsoft's strategy to become carbon negative, water positive, and zero waste by 2030.
"This is fundamentally about changing the paradigm of who gets to work on sustainability in a company," said Wilkinson. "It's not just for the people who have it in their job titles. It's about democratizing sustainability so that everybody can work on it in whatever way they want to."
In fact, a majority of employers want their subordinates' help with sustainability. In Willis Towers Watson's 2021 HR and Climate Strategy Survey, 84% of North American executives reported that employees play a major role in the successful delivery of their company's climate strategies.
It wasn't just large corporations where panelists made their mark. According to Arielle Terry, now Manager of Lending Solutions at ATMOS Financial, even a brand new employee working remotely can create positive change.
"Climate matters so much to me," said Terry. I'm so passionate about it, and I know my friends are probably like 'stop talking about it all the time.' But I just can't."
Before her current job, Terry worked as an Implementation Expert at Perceptyx, an employee experience transformation company with around 400 employees. A month into her job, Terry was shocked to learn that her 401(k) was invested into fossil fuels, deforestation, and other companies whose values did not align with her own.
"As employees, we should not have to invest in things we don't agree with," said Terry.
Before a company town hall, Terry posted a question about climate friendly 401(k) alternatives in the company Slack channel. To her surprise, her question received the most responses and was the first one asked at the town hall. After recruiting ten colleagues to a climate employee resource group, Terry eventually succeeded in convincing the company to add a climate friendly fund. She now works to improve solar lending practices at ATMOS.
While Wilkinson and Terry notched exciting wins in their respective roles, they did not come without challenge.
"A big thing is just, kind of, being ignored," explained Terry. "We were told 'we're gonna reevaluate benefits in 2023' and just being pushed off a lot."
In initial conversations with human resources, Terry learned Perceptyx did not have sustainability goals going into 2023. But by organizing coworkers and staying persistent, she still made a difference from the ground up.
Wilkinson echoed a similar sentiment.
"What it really takes to drive change for employees is a small but very tenacious and very persistent group who refuse to go away. If you can get more colleagues to join your cause, obviously it's harder to say no to ten than one, or ten thousand than a thousand."
To help individuals start their workplace advocacy, ClimateVoice developed an Employee Action Guide. The guide details four steps for all employees, regardless of title, to inspire progress: get the facts, find your influence, engage your coworkers, and advocate for action.
"No matter where you work, you have inside access. You have the relationships with your coworkers, with your leadership," said Deborah McNamara, Co-Executive Director of ClimateVoice. "Start thinking systemically about who's making the decisions and how you can have these important conversations about creating change."
ClimateVoice encourages employees to not just inspire action within the company, but also push employers to use their company's power to influence government policy.
"Right now we have this very lopsided situation where fossil fuel companies are unfortunately dominating the discourse," explained McNamara. "We want employees and companies to be doing more to advocate for the climate solutions that we need through policy."
ClimateVoice acknowledges that political engagement on climate may be daunting for some executives. That's why their guide includes a list of common objections - such as a preference for focusing on internal sustainability, a fear of wasting lobbying firepower, and a worry for pushing away partners like the U.S. Chamber of Commerce - and ideas for how employees can respond.
"It does require changing systems that are very entrenched," said McNamara. "We believe that employees are an important lever for change."
While corporate sustainability - particularly the concept of environmental, social, and governance (ESG) goals - has become controversial in recent years, companies who engage in the practice report several benefits beyond helping address climate change. Strong ESG practices increase sales, cut costs, attract investors, build customer loyalty, reduce legal liabilities, and improve recruitment with younger employees.
Panelists shared that their workplace advocacy didn't just help their companies' carbon footprints; it also helped their personal climate anxiety. A 2021 Pew Research poll found 59% of millennial and 69% of Gen-Z social media users said they felt anxious about the future after viewing climate content. While studies show excessive fear and anxiety often leads to lower engagement in the climate cause, Wilkinson's sustainability work at Microsoft allowed him to flip that script.
"For me, the antidote to anxiety is action," shared Wilkinson. "Believe that you can get power and influence. [We] are here to tell you that you surely can."
Ethan Brown wrote this article for The Sweaty Penguin.
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