Climate Break

Introduction

California Attorney General Rob Bonta has established himself to be one of California’s leading legal advocates for climate accountability. Through lawsuits against big fossil fuel companies, including ExxonMobil, Shell, Chevron, BP, and ConocoPhillips, Bonta alleges that the industry misled the public about the climate impacts of their products. As federal environmental protections face increasing challenges, he has also led legal efforts against actions by the Trump administration that California argues undermine clean energy, environmental safeguards, and climate progress.

Background

States such as California have turned to litigation as a way to preserve environmental protections and advance climate action.Many of these efforts are led by California Attorney General Rob Bonta, whose office is currently involved in 67 lawsuits, including several focused on environmental and climate issues.

Transportation remains California's largest source of greenhouse gas emissions, accounting for roughly half of the state's total emissions. In response, California adopted aggressive vehicle-emissions standards and zero-emission vehicle requirements. These standards were enabled through waivers granted under the federal Clean Air Act. Recent efforts by Congress to overturn or weaken these authorities have triggered new legal battles over the future of vehicle emissions regulation at the state level.

The Supreme Court's 2007 decision in Massachusetts v. EPA held that greenhouse gases qualify as air pollutants under the Clean Air Act. The ruling ultimately led to the EPA's Endangerment Finding, the scientific and legal determination that greenhouse gas emissions harm public health and welfare. That finding became the basis for federal greenhouse-gas regulations across multiple sectors, but notably provided an avenue for transportation regulations. The Trump administration's efforts to rescind the Endangerment Finding and eliminate vehicle-emissions standards represents one of the most significant climate-policy reversals in decades. California is suing to stop the rescission.

Beyond regulatory disputes, California has also pursued accountability from fossil fuel companies. In ongoing litigation against major oil producers, including ExxonMobil and Shell, the state alleges that companies misled the public for decades about the climate risks associated with fossil fuel use while continuing to promote products that contributed to rising emissions. 

Advantages

Litigation gives states the power to hold the federal government and companies responsible for violations of the law. By bringing cases against the federal government, states can challenge actions they believe violate environmental laws and ensure that agencies follow existing legal requirements. Lawsuits also serve as an important component of the United States' system of checks and balances, allowing courts to review government decisions and determine whether they comply with the law.

Drawbacks

Despite its potential benefits, litigation is often a slow and uncertain path to climate action. Court cases can take months or even years to reach a final resolution, particularly when they involve appeals that move through multiple levels of the judicial system. Critics also argue that major climate decisions are better addressed through elected legislatures than through the courts. While lawsuits can enforce existing laws, they cannot always provide the comprehensive policy solutions needed to reduce emissions at the scale required to address climate change.

Bonta’s Take

Attorney General Rob Bonta views litigation as one of California's most effective tools for advancing climate action and protecting environmental regulations. He argues that the courts provide a venue where disputes can be evaluated based on evidence, legal precedent, and statutory authority rather than political considerations. Through lawsuits against federal actions and fossil fuel companies, Bonta hopes to give Californians a voice in legal decisions that could affect the state's environmental future.

Bonta emphasizes that his office's role is not to pursue political objectives, but to uphold the law and the Constitution. According to Bonta, decisions about which cases to bring are guided by facts, legal analysis, and the state's responsibility to protect its residents. He argues that when government agencies or private companies violate environmental laws or mislead the public, the legal system provides an important mechanism for accountability.

About our guest

Sworn in as California’s 34th Attorney General in 2021, Rob Bonta has become a leading legal advocate for California residents. As the head of the nation’s largest state Department of Justice, he oversees efforts to protect consumers, defend civil rights, and enforce environmental laws. With a 80% case win rate in court Bonta continues to work hard to be the heart of California’s legal justice.

For a transcript, please visit climatebreak.org/advancing-climate-solutions-through-legal-action-with-rob-bonta/

Introduction to the Solution

Keeping buildings cool is becoming one of our fastest growing and energy-intensive challenges. A startup based in Hong Kong pioneers for an answer already existing in nature– the outer layer of a tiny ant that survives one of the hottest places on Earth. Dr. Martin Zhu and his co-founder mimicked the heat-repelling biology of the Saharan silver ant to develop cooling technology that remains electricity-free.

Background: From the Saharan Silver Ant to Zero-Energy Cooling

Cooling maintains around 10% of global electricity demand. In the hottest regions, cooling can account for over 70% of peak electricity demand. 

The biological inspiration behind i2Cool’s technology, the Saharan silver ant, has evolved to be a solution in the transition to zero-energy cooling. The ant endures desert heat through its surface hairs with a distinctive structure that reflects solar energy and emits body heat as radiation in a specific wavelength range. This wavelength passes through the atmosphere into outer space, effectively cooling the ant without any energy input. 

The team replicates this using engineered nanoparticles embedded in various materials, like paint coatings, window films, ceramics, and textiles. The i2Cool’s research team integrated this heat transfer principle to produce a multi-component and multi-scale solution, efficient in solar reflectivity and mid-infared emissivity of up to 95%.

Advantages

The most significant advantage of passive radiative cooling is that it requires no energy input, unlike traditional air conditioning. This technology can reduce surface temperature up to 42 ℃ and save air conditioning energy consumption by up to 40%.

In addition, since this solution is passive, requiring no electricity to run, the technology can be used off-grid or in energy-poor areas. This means the technology has the potential to democratize access to cooling in the regions of the world that need it most, but currently have the least access.

Drawbacks and Critiques

A constraint of passive radiative cooling is that the material may need to be redesigned for different climates, as Dr. Zhu acknowledges. Temperature swings and humidity in different regions require different nanoparticle structures, which is costly to implement and adjust for. This may be fine in areas near the equator where cooling demand is relatively consistent, but in seasonal climates like Russia, Canada, or the U.S., radiative cooling solutions run the risk of overcooling. 

Another drawback could be the varying and longer payback times from saved energy costs that has the potential to deter building owners from using the technology. For example, vehicle payback is under six months, while building applications take two to three years. This has the potential to deter building owners from using the technology. 

The Guest's Take

Dr. Martin Zhu sees zero-energy cooling as a powerful tool to reduce the global need for air conditioning, rather than an outright replacement. For him, this technology democratizes access to cooling while innovatively requiring no ongoing energy. This is a part of a broader vision for climate equity, sustainably leveraging technology as a means of supporting marginalized communities.

About the Guest

Dr. Martin Zhu is the Co-Founder and CEO of i2Cool, a company specializing in electricity-free cooling technology. He focuses on commercializing passive radiative cooling technology, reaching more than 30 countries.

Other Resources & Further Reading

i2Cool Company Website: i2Cool

IEA: The Future of Cooling

IEA: Keeping cool in a hotter world is using more energy, making efficiency more important than ever

ScienceDirect: Flexible passive radiative cooling inspired by Saharan silver ants

National Library of Medicine: Biomimetic Cooling

Dr. Martin Zhu Biography: Prof. ZHU Martin

For a transcript, please visit climatebreak.org/zero-energy-cooling-with-martin-zhu/

Introduction

Across Asia, Africa, and Latin America, two-wheeled vehicles are the backbone of everyday transportation. With roughly one billion two-wheelers on the road globally, their collective carbon footprint is enormous. Briz, a brand developed by Hong Kong-based One Energy (HK) Limited, is tackling this head-on with affordable electric two-wheelers paired with a rapid battery-swapping service that makes going electric cheaper than filling a tank.

Background

Two-wheelers dominate personal mobility across the Global South for one simple reason: cost. Cars remain out of reach for hundreds of millions of people, making motorcycles and scooters the primary mode of getting to work, school, and the market. They also power much of the last-mile delivery economy such as food, parcels, and pharmaceuticals in dense urban environments across Southeast Asia, Sub-Saharan Africa, and South America. Since most of these vehicles run on gasoline, they collectively represent a significant and often overlooked source of global CO₂ emissions.

Briz electric two-wheelers are designed to be price-competitive with their gas-powered equivalents from the outset. Rather than relying on home charging, which requires a stable power supply, time, and upfront infrastructure, Briz customers subscribe to a battery-swapping service. When the battery runs low, riders visit a nearby swap station, slide out the depleted battery, and click in a fully charged one. The company says the swap takes under a minute. Critically, the monthly cost of the swapping service is designed to be lower than what a rider would typically spend on gasoline, lowering the financial barrier to switching.

One of the most persistent obstacles to electric vehicle adoption in emerging markets is charging time. Early Briz models required up to five hours to recharge, a dealbreaker for riders who depend on their vehicles for daily income, but the battery-swap model sidesteps this entirely. It also removes battery degradation. Since customers are subscribing to a service rather than owning a battery outright, the often steep cost of battery replacement falls on the operator, not the individual rider.

Advantages

By targeting a vehicle category that has historically been overlooked in the electrification conversation, Briz has the potential to generate outsized climate impact. Electrifying even a fraction of the world's one billion two-wheelers, especially in regions where electricity grids are increasingly powered by renewables, could deliver meaningful reductions in transport emissions. The business model is also structured to work for people with lower and irregular incomes: the subscription pricing removes large upfront costs, and the swap infrastructure means riders aren't dependent on owning or accessing home charging equipment.

Drawbacks and Critiques

The battery-swap model works well in cities and dense corridors with swap station coverage, however it creates real limitations for long-distance travel. Riders venturing beyond the swap network face the same range anxiety that affects all battery electric vehicles. Expanding station infrastructure into rural and peri-urban areas will be essential and expensive if the model is to reach its full potential.

Safety is another concern. Battery swap stations concentrate large numbers of lithium-ion cells in a single location, creating a fire risk. One Energy says its stations are equipped with automatic fire-extinguishing systems designed to respond to any battery fire before it can spread, but the risk is worth monitoring as the network scales.

Kevin To's Perspective

Kevin To, CEO of One Energy (HK) Limited, brings the operator's view to the challenge of electrifying the world's most common vehicle. His company's approach of supplying affordable hardware, subscription-based battery access, and a focus on markets where two-wheelers are a necessity rather than a lifestyle choice reflects a pragmatic bet that climate solutions need to make economic sense for the people adopting them, not just for investors or policymakers.

About Kevin To

Kevin To is the CEO of One Energy (HK) Limited, the parent company behind the Briz brand of light electric vehicles. Based in Hong Kong, he leads the company's efforts to bring affordable, battery-swappable electric two-wheelers to mass markets across Asia and beyond.

Further Reading

Briz LEV — Official website

IEA: Global EV Outlook — Two- and Three-Wheelers

Bloomberg NEF: Electric Vehicle Outlook

For a transcript, please visit climatebreak.org/electric-two-wheelers-with-kevin-to/

Impacts of Air Transportation on Climate Change

Air transportation is a major contributor to the fossil fuel economy: studies have shown that aviation is responsible for 3.5 percent of all drivers of climate change from human activities. Planes use immense amounts of kerosene—a flammable liquid used as fuel—in order to travel. When kerosene burns, it releases greenhouse gases like carbon dioxide and black carbon. Also, planes create contrails: “line-shaped clouds produced by an airplane’s hot engine exhaust interacting with cold humid air several miles above the Earth’s surface.” These are the lines of white you see behind a plane as it flies overhead: small water particles from the plane’s engine exhaust that have frozen to become visible ice crystals. Because these are essentially clouds, when they persist past a short period of time, they have the potential to trap heat in the atmosphere, leading to a warming effect with many negative climate change consequences.

Advanced Air Mobility as a Climate Solution

In order to combat these negative effects of air travel—and to keep up with increasing demand for shorter distance air travel—researchers have begun looking toward opportunities for low emission options that can be more widely applied. This concept has been coined Advanced Air Mobility (AAM), and seeks to develop transportation technologies which are: “highly automated, electrically powered, and have vertical take-off and landing capability.” One main goal of the project is to develop Urban Air Mobility (UAM) in order to connect underserved communities within cities and rural regions.

Ideally, Advanced Air Mobility will be an environmental improvement because it will use cleaner forms of energy to fuel the transportation, from electricity to hydrogen. According to Adam Cohen of UC Berkeley’s Transportation Sustainability Research Center, there are several different potential uses for the cleaner energy technology, including air taxi services, small package delivery, emergency services, or aeromedical use cases. Airports in particular are confronting a lot of demands for power—both in terms of aviation and ground vehicles—which electric fueled AAM may be able to help fulfill. In terms of hydrogen power, Cohen says manufacturers are testing and have prototypes for a hydrogen aircraft in the hopes that hydrogen will be an entry point for more sustainable flight in the future.

Challenges of Implementation

AAM is still in its early stages of development, and has yet to be implemented in a real way. In order for this to occur, its innovators need to place safety and integration at the forefront, ensuring passenger and cargo safety, as well as minimal disruption to current air traffic pathways. Further, it will be necessary to ensure some level of equitable access in terms of both convenience and cost across groups of people. Ultimately, AAM hopes to be a step in the direction toward clean energy in the aviation sector, encouraging policies and technologies in line with sustainable goals.

About our guest

Adam Cohen is a transportation thought leader, consultant, and shared mobility researcher at the Transportation Sustainability Research Center at the University of California, Berkeley. Since joining the group in 2004, his research has focused on innovative urban mobility solutions, including shared mobility, smart cities technologies, smartphone apps, urban air mobility, and other emerging technologies.

Resources

Federal Aviation Administration: Advanced Air Mobility

National Business Aviation Association: Advanced Air Mobility

NASA: Advanced Air Mobility

For a transcript of this episode, please visit https://climatebreak.org/advanced-air-mobility-with-adam-cohen

Introduction to the Solution

UC Davis researchers are examining a novel approach to combating climate change: turning our buildings into carbon sinks. The solution is based on incorporating biochar, a carbon-rich material obtained from plant material, into common construction materials like concrete, brick, and asphalt. By embedding carbon directly into long-lasting infrastructure, this approach reduces atmospheric CO₂ and also transforms one of the most carbon-intensive industries in the world into a tool for climate mitigation.

Background: How Carbon Storage in Building Materials Works

Biochar is created through pyrolysis, a process involving heating organic material, such as crop residues or wood waste, in a low-oxygen environment. This process locks in carbon that plants absorb during photosynthesis and prevents it from being re-released into the atmosphere through decay or burning.

The research team at UC Davis, headed by Professor Sabbie Miller and Dr. Elisabeth Van Roijen, proposes the use of biochar as a partial replacement for the materials in concrete and other construction compounds. Since more than 20 billion tons of concrete are produced every year by the construction sector, substituting 10% of that with biochar-based mixtures could store up to 1 gigaton of CO₂ annually, or the equivalent yearly emissions from Japan.

Unlike temporary carbon storage methods, like soil burial, embedding biochar in durable infrastructure ensures long-term sequestration, potentially spanning decades or even centuries. It also leverages the global scale of construction as a medium for climate action.

Advantages of This Solution

Apart from net carbon emissions reduction, the introduction of biochar-enriched building materials has tangible engineering benefits. It has been found that the addition of biochar can enhance thermal insulation, fire resistance, and durability in some uses. The process also fits well within the circular economy principles because of the organic waste used and reduced need for virgin materials.

Because construction is already a high-volume, resource-intensive industry, integrating biochar into existing supply chains could make climate-positive practices scalable and economically viable without requiring dramatic infrastructure overhauls. Equally important, this solution provides dual benefits: supporting both carbon sequestration and the development of sustainable materials.

Drawbacks and Critiques

The approach faces several scientific and logistical obstacles despite such a promising premise. Producing biochar requires energy in quite significant quantities, with sourcing biomass at large scales risking unforeseen ecological impacts such as nutrient depletion or habitat disruption. Some critics even ask whether its broad adoption might inadvertently encourage the removal of older buildings in favor of the construction of newer, carbon-storing ones, offsetting any climate gains.

Another factor is the life cycle of the biochar-infused materials themselves. While they can store carbon for decades, it remains undetermined how these materials at the end of a building's life are to be managed to avoid re-release of CO₂. Future policy frameworks and recycling technologies will be required to address these challenges if there is to be long-term effectiveness.

About the Guest

Dr. Sabbie Miller is an Associate Professor of Civil and Environmental Engineering at UC Davis. Her research focuses on sustainable infrastructure materials, life-cycle assessment, and reducing the environmental footprint of the construction industry.

Further Reading

UC Davis News: Storing Carbon in Buildings Could Help Address Climate Change

Nature Geoscience: Carbon Sequestration Using Biochar

Science Magazine: Building Materials as Carbon Sinks

ScienceDirect: Alternative Sequestration Options in Construction Materials

For a transcript, please visit https://climatebreak.org/sequestering-carbon-in-building-materials-with-dr-sabbie-miller/