For the first time, nations around the globe have resolved together at the U.N. climate summit to “transition away” from the use of fossil fuels to curb how much the planet warms due to human activity.
Though the new agreement struck at COP28 in Dubai leaves many questions unanswered, slashing global greenhouse gas emissions in half by the end of the decade has already been established as a crucial target to mitigate otherwise unavoidable catastrophe.
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The Biden administration has committed to this goal, but so far the United States, one of the world’s top emitters, isn’t on track. Halving emissions by 2030 would require “five times the pace of [current annual] emissions reductions,” said John Bistline, a program manager in the Energy Systems and Climate Analysis group at the Electric Power Research Institute.
As that deadline looms just six years away, experts say the nation has options to make the major changes and investments necessary to meet that target, especially by focusing on emissions reduction efforts within its top-polluting economic sectors.
At COP28 – the annual international conference that wrapped up Wednesday – world climate negotiators approved a document, known as the global stocktake, that pledges for the first time to move away from the use of fuels like oil, gas and coal, though critics note it contains significant loopholes. Nations also agreed that in order to limit warming to 1.5°C above pre-industrial temperatures, global greenhouse gas emissions would have to be reduced by 43 percent by 2030 compared to 2019 levels.
Though the 2015 goal to cap warming at 1.5°C remains intact, the central document established at the end of COP28 acknowledges that humanity isn’t doing enough right now to pull that off.
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United Nations Climate Secretary Simon Stiell called the agreement a “climate action lifeline, not a finish line.”
The reason to cap warming is simple, even if the solutions are not: As the Earth’s temperature climbs, so too does the rate of climate change-driven catastrophes like floods and heat waves, rising seas and dwindling biodiversity.
Between 2005 and 2022, the U.S. reduced economy-wide emissions by about 16 percent, or around one percentage point per year on average, Bistline said. To meet the 2030 goal, the U.S. would have to ramp up to five percentage points annually.
Though ambitious, researchers say it is possible. Clean energy technologies have become dramatically cheaper and more efficient in recent years, said Nikit Abhyankar, a senior scientist at the University of California, Berkeley.
“This is the first time in history where [the] technology, economics and environmental sustainability of our energy options [are] really aligning and pointing in the same direction,” he said.
Five economic sectors in the U.S. — electric power, transportation, industry, buildings and agriculture — together account for the nation’s main sources of greenhouse gas emissions. Each sector has options it can pursue to decarbonize, and there are ample tools available – from electrification to improving energy efficiency to carbon removal and other efforts – to pursue this transition in equitable and affordable ways, Bistline said.
“There’s not a one-size-fits all approach to decarbonization… ” he said. “A lot of these approaches are really tailored to different regions of the country. So that’s something that, even though we talk a lot about results at [the] national level, I think a lot of the impacts hit locally and may look pretty different depending on where you are.”
Here’s a look at some ways experts say the U.S. can decarbonize, and what it will take.
Graphic by Megan McGrew/PBS NewsHour
1. Electric power
How does this sector contribute to emissions?
Electricity generation is one of the biggest sources of greenhouse gas emissions in the U.S. The electric power sector alone accounted for a quarter of national emissions in 2021. Those emissions resulted from the burning of fossil fuels like natural gas and coal to generate electricity, according to the Environmental Protection Agency.
Other sectors use electricity in their daily operations. When that use was factored into their respective footprints, industry and buildings made up the largest shares of total emissions in 2021.
“That is why the electric power sector is one of the most important sectors to decarbonize first — to enable economy-wide decarbonization faster,” Abhyankar said. Heating or lighting a building with electricity generated from renewables instead of fossil fuels, for example, would reduce its emissions footprint.
What are some ways this sector can reduce emissions?
About 80 percent of the electric grid would need to be powered by clean technologies by 2030 if the U.S. is to meet its economy-wide emission reduction target, Abhyankar explained.
The country is falling “pretty short on achieving that target” so far, he said, adding that reaching it would require boosting wind, solar and battery capacity to three to four times the current rate through 2030 and beyond.
Government initiatives including the 2022 Inflation Reduction Act (IRA) have offered economic incentives that make the choice to pursue new renewable energy projects more attractive to decision-makers in the energy industry.
Rows of solar panels are pictured at the Toms River Solar Farm, which was built on an EPA Superfund site in Toms River, New Jersey, U.S., 26 May, 2021. Dane Rhys/Reuters
State mandates like those in California — where all utilities are required “to procure at least 60 percent of their total energy from clean sources by 2030 and 100 percent by 2045” — also help move the needle, Abhyankar said.
There is a significant number of pending renewable energy products in the U.S., but he noted that one hold up is the lack of transmission capacity — or the ability for the existing electrical grid to take in electricity generated from those projects — to make them possible.
What changes can make these reductions possible?
Phasing out fossil fuels and increasing renewable energy sources will require major changes in the power sector. Unlike fossil fuels, which can be burned to generate electricity at any time, wind and solar sources are intermittent. Abhyankar said that means utilities have to be able to store and share electricity with each other as needed.
Demands on the electric grid are also projected to increase due to decarbonization efforts across sectors, he noted, such as the push to get more electric cars on the road, which would result in far more people charging their vehicles at home rather than filling up at gas stations.
The 2021 Bipartisan Infrastructure Law allocated $2.5 billion to incentivize improvements to the electric grid. Building new transmission lines takes years, Abhyankar said, but upgrading existing ones with new materials that increase the amount of electricity they can transmit is an option to boost capacity more quickly.
“Without changing your transmission structures, without changing the voltage, without acquiring any new right of way — just changing the physical lines and replacing them with these new conductors, you can double the transmission capacity just like that,” Abhyankar said.
How would these changes affect life in the U.S.?
The power sector is a key player in the effort to meet the nation’s emissions reduction goals. A combination of that sector and the transportation sector is projected to account for 69 to 89 percent of target emissions reductions by 2030, according to a 2022 analysis of several models that Bistline and Abhyankar co-authored.
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Making these changes would have major implications for public health, too.
“If you clean up [the power sector] by, say, 80 percent by 2030, 90 percent [by] 2035 and a near 100 percent – say, 95 percent or above – by 2050, you’re talking about avoiding more than [a total of] 100,000 premature deaths because of air pollution from the electricity generation source,” Abhyankar said.
2. Transportation
How does this sector contribute to emissions?
Planes, trains and automobiles – the transportation sector accounts for the movement of people and goods by all these methods and more, according to the EPA. A Congressional Budget Office report found the majority of carbon dioxide emissions from this sector comes from cars and trucks.
What are some ways this sector can reduce emissions?
Reducing the number of gas-powered cars on the road would decrease direct emissions, and the push to popularize EVs also emphasizes the imperative of cleaning up the electricity grid.
“We are shifting from gas to electricity to run our vehicles,” Abhyankar said. “So the electricity has to be clean for the vehicles to maximize emission reductions.”
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Building up charging infrastructure is an important consideration, though Abhyankar noted that batteries are increasingly able to charge faster thanks to technological advancements, and most newer EVs have a standard range that would meet most people’s daily needs.
The outsized contribution to the emissions problem by the cars we drive is part of the rationale behind the IRA’s electric vehicle tax credits for consumers that will reduce the total price at the point of sale beginning in 2024.
What changes can make these reductions possible?
A 2023 analysis of several models that Bistline co-authored looked at how IRA incentives could allow for 43 to 48 percent emissions reductions across the economy below 2005 levels by 2035. That study found that the IRA paves the way for light duty electric vehicles to make up 32 to 52 percent of new car sales by 2030, and the paper notes those sales would “decrease or flatten between 2030 and 2035” when the IRA’s tax credits expire.
A charging handle recharges a Volkswagen ID.4 electric vehicle (EV) parked at an EV charging station inside a parking garage owned by the City of Baltimore, in Baltimore, Maryland, U.S., March 23, 2023. Bing Guan/Reuters
But just how much of a dent EVs can put in U.S. emissions hinges on their accessibility and affordability, and general consumer behavior — those tax credits won’t do much good if people don’t or can’t easily take advantage of them.
Government mandates play a role in the transportation sector, too. In California, Abhyankar said, the Zero-Emission Vehicle (ZEV) program stipulates a mandatory minimum percentage of new vehicle sales that must be zero-emission, and that minimum increases annually. From there, it’s up to companies to figure out how to successfully market those cars to consumers.
How would these changes affect life in the U.S.?
Although major existing incentives focus on passenger cars, Abhyankar emphasized that trucks and trains are important to consider from both a climate and an environmental justice perspective.
About a third of road transport emissions come from heavy-duty vehicles, or trucks, and most trains in the U.S. — including those that run through residential areas — are diesel-electric, he said. That’s an important consideration because of the ways that air pollution affects health.
“Communities of color, people of low income and front-line communities are disproportionately affected by the air pollution [generated by] trucks and trains,” Abhyankar said.
Electrifying most new vehicle sales by 2035 in the U.S. would avoid a total of nearly 150,000 premature deaths between now and 2050, he noted.
3. Industry
How does this sector contribute to emissions?
Consumer demand for “the latest and greatest” products and rising standards of living globally contribute to the industry sector’s sizable environmental footprint, said Nabil Nasr, associate provost and director of the Golisano Institute for Sustainability at Rochester Institute of Technology.
The EPA’s calculation of industry emissions include those from manufacturing facilities, plus the ones associated with generating the electricity they use.
What are some ways this sector can reduce emissions?
Nasr is also CEO of the REMADE Institute, a federally funded organization that supports technological innovations to boost sustainability across industry. He and his colleagues advocate for a circular economy that he said focuses on “reducing the environmental impact of products through many factors” and “designing waste out of the process.”
Nasr pointed to multiple paths toward making that economic structure a reality. One is increasing recyclability — especially for hard-to-recycle materials like plastics — and both designing products to be made out of recycled material and creating a market where manufacturers can access those resources in the first place.
Another is remanufacturing, or giving a product new life at the end of its use by cleaning, replacing and/or restoring specific parts so that the whole can once again be used by a consumer. He also advocates for the reduction of embodied energy, or the total energy used to create a product, throughout the manufacturing process.
What changes can make these reductions possible?
Some of the major barriers facing the industry sector today are a lack of awareness of and funding for these production approaches, plus a lack of infrastructure to support them, Nasr said.
He advocates for more investment in technologies that would support a circular economy, and noted that governments can promote the adoption of innovative products though their own purchasing power.
Between commitments made by companies and the emissions reduction strategies laid out by the Biden administration, industry has clear paths forward in the effort to decarbonize. Nasr noted the sector could play a major role in meeting the nation’s longer-term aim of reaching net-zero emissions by 2050.
Solar panels are built at the QCells solar energy manufacturing factory in Dalton, Georgia, U.S., March 2, 2023. Megan Varner/Reuters
He said he’s optimistic, and that there are plenty of opportunities for the industry sector to achieve emissions reduction targets, adding that people can “move mountains” when they work together or establish a common focus.
“The challenge, I think, is that it’s not just about industry. It’s not just about technology. There’s also the importance of implementing those technologies — make them happen, have the infrastructure, have the investment available to make some of those transitions,” Nasr said.
How would these changes affect life in the U.S.?
Just how much consumers would be privy to the kinds of changes to the industry sector Nasr advocates for depends on the product. He noted that some lower-emitting products — like electric vehicles — differ in obvious ways from their counterparts, but others likely wouldn’t differ much at all. If anything, he said, the goal is for products to stay the same or improve.
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“Many times [changes] will be unseen to the consumer because it’s huge enhancements in the process that we use to make the product, and the consumer would not necessarily see a lot of that, but they are getting a product that is identical to what they used to get,” Nasr said. “Other cases, I think you might see some radical enhancements and changes.”
On the consumer level, the “right to repair” movement advocates for changes that align with the vision of a circular economy. Advocates push for legislation and regulation that would make it easier for consumers to repair the products they’ve purchased to continue using them rather than purchasing a new replacement, among other changes.
4. Buildings
How does this sector contribute to emissions?
The buildings sector covers both residential and commercial buildings. A range of factors — including the combustion of fossil fuels for heating and cooking, plus off-site emissions associated with electricity use and the production of building materials – contribute to the sector’s environmental footprint.
What are some ways this sector can reduce emissions?
Many older buildings remain inefficient because they were built under decadesold codes and retrofitting them with better insulation and greener technologies is expensive, said Jasmina Burek, assistant professor of mechanical and industrial engineering at UMass Lowell.
An energy-saving heat pump installed in a home. Photo via Getty Images
Burek noted that optimizing insulation is one key step toward optimizing the efficiency of buildings old and new. Without good insulation, green technologies like solar panels or heat pumps — which the IRA has incentivized for homeowners with tax credits — can’t reach their maximum potential for energy demand reduction.
What changes can make these reductions possible?
The EPA says reducing leaks and improving energy efficiency are two steps that property owners can reduce emissions. On the manufacturing side of things, cutting costs for greener building materials and technologies will also be key to making more accessible options that are efficient — and climate resilient, Burek noted — for more people, including those who are lower-income.
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The federal government has issued a set of standards that emphasize sustainability in buildings it builds or leases out. Voluntary programs like LEED certification incentivize businesses to build better on the commercial side of things, Burek noted. The Department of Energy also offers home energy assessments that can help homeowners identify and fix energy inefficiencies, plus tips on how they can conduct those types of assessments themselves.
How would these changes affect life in the U.S.?
More efficient buildings would cut costs associated with heating, cooling and other utilities. Homes with better insulation have lower energy bills, and heat pumps are associated with savings, too.
5. Agriculture
How does this sector contribute to emissions?
Two specific greenhouse gas emissions, nitrous oxide (N2O) and methane, are heavily associated with agriculture, according to the EPA. Soil management — including the use of fertilizers — is tied to a little more than half of emissions from the sector, while methane production from the digestive processes of livestock accounts for around a quarter, the agency said.
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Another source of pollution is carbon dioxide that can be emitted from soil. Soil stores carbon in the form of organic matter, but disturbing it through processes like tilling negates that benefit, releasing CO2 into the atmosphere, said John Field, a researcher at Oak Ridge National Laboratory, which is funded by the Department of Energy.
What are some ways this sector can reduce emissions?
Agriculture, like other sectors, has options when it comes to being part of the emissions solution. Field’s research focuses on how to store more carbon in the soil to keep carbon dioxide out of the atmosphere, which can be achieved with relative ease with steps like the planting of cover crops. Field also explores how to use biomass, derived from organic materials like crops, to create novel energy sources that can be cleaner alternatives to fossil fuels.
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That’s important because, although electrification is a key step toward decarbonizing the U.S. economy, it can’t be applied universally. Some ubiquitous aspects of our modern life still run on combustion engines.
“There are some sectors of the economy that are still very difficult to electrify,” Field said, pointing specifically to the transportation sector, where airplanes, ships and other vessels are a long way off from being powered solely by electricity.
FILE PHOTO: Cows are sorted into pens for a livestock auction in Dickinson, North Dakota, U.S. Aug. 17, 2017. Andrew Cullen/Reuters
The EPA also lists optimizing the amount of fertilizer that’s applied to croplands, interventions to reduce methane emissions among livestock and pursuing new uses and disposal methods for manure as ways the agriculture sector can reduce emissions.
What changes can make these reductions possible?
Reducing all emissions associated with agriculture is crucial to combating climate change. But Field said soil carbon sequestration efforts are available to the sector right now to help cut down on CO2, even as technological advancements for other emissions reductions strategies may take more time to emerge.
