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Engineering Responses to Climate Change: Proceedings of a Forum (2022)

Chapter: 2 Mitigation and Adaptation

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Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
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2

Mitigation and Adaptation

At the beginning of the question and answer period, Bell asked about the relative emphases given to mitigation and adaptation in responding to climate change. “Do we focus on one more than the other, or both?”

Shoemaker observed that “even if we did everything to mitigate climate change today, we’d still be living with 30 years of wild weather” due to past emissions of greenhouse gases. Adaptation will therefore be essential, both through the engineering of hard infrastructure and through nature-based solutions. Furthermore, adaptations will not be limited to particular parts of the country. For example, the 2021 wildfires in California reduced air quality across the entire United States. “You could live in the most pristine part of the United States and still have an air quality problem. That was eye opening for all of us.”

Some of the need for adaptation is difficult to foresee today, Shoemaker added. For example, even small changes in temperature can have huge effects on agriculturally linked economies. Many countries will need new crops, new food systems, and new ways of coping with a changing climate. Extremely high temperatures will also make it increasingly difficult for people to work outside. Many communities will need a great deal of help in adapting to the changes that are occurring and on the way, she said.

CARBON CAPTURE AND SEQUESTRATION

Achieving the massive decarbonization that is needed by the middle of the century will require that continued greenhouse gas emissions be offset through what are known as negative emissions technologies, which

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×

remove carbon from point sources or from the atmosphere and utilize or sequester that carbon. In fact, said Catherine Peters of Princeton University, many analyses predict that negative emissions technologies will play as significant a role as any of the low-carbon technologies needed for decarbonization.

Research being done today on negative emissions technologies is “very promising,” said Peters. Carbon capture from a concentrated gas phase like a power plant smokestack or directly from the air is an old technology, having historically been done with liquid amine solutions. Today, researchers are examining solid sorbents, which are far more efficient than amine solutions in both recovering carbon dioxide and regenerating the sorbent. For example, Claire White and her associates at Princeton University have been developing layered double hydroxides that have tunable selectivity to absorb carbon dioxide. “These materials have a good balance of low cost, high absorption capacity, and moderate energy needs for regeneration,” said Peters.

Once carbon is captured from the atmosphere, it needs to be used or sequestered so that it cannot return to the atmosphere. One way to do this is through carbon mineralization, in which carbon dioxide reacts with metals to form thermodynamically stable carbonate minerals. The materials needed for these reactions are alkaline substances, which fortunately are abundantly available from existing industries. For example, the coal ash generated in the United States alone could capture an estimated 40 million to 200 million tons of carbon dioxide per year, said Peters. Furthermore, carbon mineralization can help immobilize heavy metals like arsenic, copper, and cadmium, thereby reducing heavy metal pollution.

Another way to isolate carbon dioxide from the atmosphere is to inject it into rock formations deep underground. For nearly 20 years, Peters’ research has focused on whether carbon dioxide would leak from where it is sequestered, and she and her students have concluded that this is “highly unlikely.” Because of the long history of oil exploration, most underground reservoirs have been explored in some way. Modern petroleum engineering practices do a good job of abandoning and shuttering old wells, though previous practices were not as good, creating the possibility that some formations are perforated in ways that could render them leaky. But leakiness can be assessed before an injec-

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×

tion project begins by testing whether a formation can hold pressure, and formations demonstrated to be leaky can then be avoided.

Another factor is that carbon dioxide, unlike methane or natural gas, is highly soluble in water, which is one of the reasons it remains trapped underground. If it is injected deep underground, even if it does leak away from the target formation, it will encounter so much water that it is highly unlikely to get all the way to the land surface. Other trapping mechanisms—“even ones that we didn’t expect”—would help keep carbon underground. “In my opinion, geologic carbon sequestration is a technology that is ready to go. What is needed is a stream of captured carbon for injection.”

Injecting carbon dioxide underground could even be used as a source of energy, Peters noted. Jeffrey Bielicki at Ohio State University and his colleagues have been studying the use of carbon dioxide to store energy underground, whether as heat in a geological formation, heat in a carrier fluid, or mechanical energy. “They have determined that subsurface energy storage has enormous capacity and energy discharge potential,” she said.

Civil and environmental engineers “are well positioned to lead technological advances in decarbonization and negative emission strategies,” Peters concluded. “I’d like to think that when we look back on this 10 or 20 years from now, we can say that we created a whole new body of science that collectively is a new carbon-negative way of doing things.”

AIRCRAFT

A particular focus of the discussion was air travel, which accounts for about 10 percent of greenhouse gas emissions from the transportation sector.

A significant effort is under way to develop small flying vehicles powered by electric motors, observed Washington. These aircraft take advantage of lightweight materials and new battery chemistries with very high power densities to travel medium distances. These are distances too long to drive and too short for large passenger aircraft, for example in the 300- to 400-mile range, or even 200 miles and less, such as between San Jose and San Francisco or New York and Washington, DC. “Those are perfect for electric aircraft like the vertical takeoff and landing vehicles that are being considered,” Washington said. Such aircraft still face hurdles in terms of safety certification, but the technology is moving to the point where it is relatively proven.

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×

It is not feasible for large-scale aircraft to be all electric—“they’re just massive,” said Lieuwen. But work is being done on renewable fuels—both biologically based drop-ins that could replace current jet fuels and new kinds of fuels like hydrogen that would require different engines and airport infrastructure. Either option “scales nicely across all different sizes and platforms of vehicles,” Lieuwen said.

Another possibility is hybrid aircraft. Airplanes need most of their power to take off; cruising takes much less power. A hybrid airplane that combines electrical systems with a traditional gas turbine powerplant would allow aircraft engineers “to completely re-vision what the overall aircraft looks like,” observed Lieuwen.

ARTIFICIAL INTELLIGENCE

In response to a question about the anticipated effects of artificial intelligence on engineering responses to climate change, Washington noted that “artificial intelligence is rushing into our lives at an amazing rate. We’ve seen devices that you don’t even know have AI in them that do. And if AI isn’t in the device itself, the device is connected to the cloud and is pulling on AI and analytics in the cloud.”

Shahidehpour added that the levelization of electricity loads will be impossible to implement without AI. Such programs not only analyze data but help determine what kind of data are needed to manage energy use and guide customer choices.

AI tries to understand the nature of a system from the data that the system is producing, Lieuwen explained. Many companies are using these data-driven approaches to work at the intersection of knowledge and expertise. For example, a company that he founded, Turbine Logic, does this for solar farms and gas-fired power plants, with significant applications in monitoring and diagnostics to make the grid more resilient. “It’s probably an $80 billion market per year, simply using better analytics to operate what we have more efficiently.”

Because of the breakneck growth of AI, the energy that AI computer chips consume is also growing at a very rapid pace, and the engineering community has a role in reducing this energy usage, said Washington. The right types of processors and computational architectures are

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×

needed to make AI systems as computationally and energy efficient as possible. “AI is here to stay, and it’s only going to grow in demand, because it’s making people’s lives better, and it’s making everything that we do more efficient and more enjoyable. I don’t think the answer is tapering down the use of AI. The answer is designing the AI and the computational architecture underneath that to be more efficient and more effective.”

More generally, Washington added, the advent of AI, like the need for adaptation, points to the unpredictability of future developments. “If you could wind the clock back 5 years ago, what were we thinking about what 2021 was going to look like, how accurate was our prediction?… Technology is going to accelerate to a point, 5 years from now, where we won’t recognize the pace of innovation.” As an example, he cited recent work he has been doing on consumer robotics; 5 years from now, he said, every home and every business is likely to contain at least one robot. “We need to not just think about today but about 5 to 10 years from now and how technology will shape what our lives will look like.”

CORPORATE INITIATIVES

In 2019 Amazon cofounded the Climate Pledge and announced its commitment to achieve net zero carbon emissions across its business by 2040. The overarching goal, said Amazon’s Ken Washington, is net zero not just for Amazon’s business operations but for the full impact of its business, from the acquisition of materials to the manufacturing, shipment, energy use, and disposal or other postuse of its products. “When you think about what makes a device sustainable, you have to consider all aspects of this value chain.”

Lifecycle assessments of its products revealed, somewhat surprisingly, that on average more than half of a device’s total carbon footprint comes from the electricity it uses during operations. The next biggest impact is emissions generated by the acquisition of materials and the manufacturing processes needed to transform raw materials into products. “These are the two areas where we put our focus.”

One approach has been to roll out low power modes for new devices and to update and upgrade older devices to use less power during moments of inactivity. “But this isn’t enough,” said Washington.

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×

To address the electricity used by its devices, Amazon became the first electronics manufacturer to commit to putting renewable energy onto the power grid. Just before the forum, it announced that it was making investments in wind and solar farm capacity such that by 2025 it will produce enough clean energy to power all its Fire TV and Echo devices. “We expect this will produce more than 5 million megawatt-hours of clean energy per year—enough to power more than 400,000 homes.”

Amazon also has sought to incorporate recycled and renewable materials in its products and has both reduced waste in its packaging and boosted its trade-in and recycling programs to keep devices out of landfills. It has sought to raise consumer awareness about the products they buy. For example, it is now badging products that have achieved sustainability certification, highlighting products with a low-power mode, and providing consumers with energy dashboards when they are shopping to promote more sustainable products.

People want to do things “that are easy,” said Washington. “We as engineers and technologists have to step up and make it easy for people to do the right thing when it comes to sustainability.” For example, the badging program on Amazon’s website makes it easier for customers to pick low-energy devices, and technology can help shift activities to periods when energy use has less of an impact. “Technology has to play a huge role in making it easy to do the right thing.”

Other companies are taking or could take similar steps to limit climate change, including companies that sell their products on Amazon’s platform. “If every company had an analogous set of commitments to make a difference like this,…that’s going to put a big dent in this problem, because the economy is primarily driven by commercial industry.” Furthermore, these commitments could change not only how people choose and use technology but the broader culture.

Climate change is not a problem that will be solved in a few years, “because we created this problem over decades, and it’s going to take decades to solve it,” Washington said. “We don’t have as long as we’d like, but little things matter, and we have to continue to have momentum through these little and in some cases not so little acts that change the mindset and the culture, because the mindset of the population will be behind the right policies to make bigger changes.”

Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
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Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
Page 12
Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
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Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
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Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
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Suggested Citation:"2 Mitigation and Adaptation." National Academy of Engineering. 2022. Engineering Responses to Climate Change: Proceedings of a Forum. Washington, DC: The National Academies Press. doi: 10.17226/26458.
×
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At the forum held during the 2021 annual meeting of the National Academy of Engineering, distinguished engineers gathered virtually to explore the roles that engineers can play in both mitigating and helping society adapt to climate change. Through a series of brief presentations and responses to questions from the moderator and the forum audience, the speakers discussed many of the issues at the forefront of climate-related engineering practice and policy today. This publication highlights the presentation and discussion of the event.

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