A drone flies over a field of crops, capturing green and brown swaths of land. When you examine the pictures more closely, you notice that portions of the soil are covered in a dusting of chalky white powder. Nope, it isn’t fungi; it’s actually crushed limestone that's been spread to facilitate natural carbon capture. This was one of several pioneering solutions Brad Marston, a professor of physics at Brown University, touched upon during his lecture, ‘Can Physics Stop Climate Change?’, organized by the Department of Physics and Astronomy on Thursday, April 23rd, 2026.
Marston opened with a picture of the Keeling Curve. This iconic line graph plots atmospheric carbon dioxide (CO2) concentration, as measured at the Mauna Loa Observatory, over time. The main graph shows a steady increase in CO2 concentration, driven by fossil fuel combustion and cement production. There’s also an inset graph showing seasonal variations in CO2, with a drop in spring as plants absorb CO2 during growth, followed by a spike in autumn as organic matter decays, releasing CO2. Finally, the black line beneath the seasonal cycle corresponds to variations due to El Niño, the largest climate oscillation on human time scales.
“Besides that temporal signature, there’s also some interesting spatial signatures of [that] warming,” Marston said, showcasing a plot depicting how the extent of global warming varies with latitude. The Arctic, for example, experiences intense warming, a phenomenon known as arctic amplification. This is because melting sea ice exposes the dark ocean beneath it. This has a lower albedo than white ice, increasing the proportion of sunlight absorbed rather than reflected.
In 2015, Quirin Schiermeier wrote a Nature editorial titled “Climatologists to physicists: your planet needs you.”
“It was a call to mainstream physicists, physicists in departments such as this one, to think about applying the techniques and tools that have been applied in different specialities in physics, to the climate system,” Marston said.
Marston divided the areas where physics expertise is needed into three categories: understanding climate change, reducing CO2 emissions, and repairing climate systems. To help the audience understand climate change from a physics point of view, Marston began by treating the Earth as a black body, a surface that absorbs all incident radiation. Then he used the Stefan-Boltzmann Law, which states that the power radiated by a black body is directly proportional to the fourth power of its absolute temperature. After accounting for the fact that only 70% of incoming solar radiation is absorbed and that Earth absorbs it through a disc, he computed Earth’s surface temperature to be -18°C. While this value is the right order of magnitude, it certainly doesn’t reflect actual surface temperatures.
This is because the simplistic model fails to account for an atmosphere containing greenhouse gases. Two of these gases are of special note. Water vapor has a permanent electric dipole moment since oxygen is more electronegative than hydrogen. This dipole moment changes during molecular vibration, allowing water to absorb infrared radiation. Carbon dioxide doesn't have a permanent dipole, but asymmetric stretching and bending create temporary dipole moments that allow it to absorb infrared radiation.
“The first person to realize that water vapor and carbon dioxide can couple with infrared radiation was a scientist named Eunice Newton Foote,” Marston said.
A brief survey of the room revealed that few people knew who Newton Foote was, suggesting that her contributions were insufficiently highlighted in history. To honor her efforts, the American Physical Society is creating an award in her name to support climate physics research.
This kind of research spans many seemingly unrelated branches of physics. Consider the quantum Hall effect, in which a conductor is placed in a magnetic field, and its resistance changes in discrete steps since electrons are forced to travel through specific paths.
“It turns out that the Earth’s climate system also has waves traveling around a boundary. This is [something] called an equatorial Kelvin wave… and we showed that this wave has the same mathematical origin as the electron waves in the quantum Hall effect,” Marston detailed.
Marston believes that this connection could have been uncovered earlier if not for the siloing of science into subdisciplines, which stymies interdisciplinary connections.
Marston then elucidated how physics can be leveraged to reduce CO2 emissions. He began by highlighting the utility of solar energy, illustrated by the fact that it accounted for more than 25% of the increase in global energy supply in 2025. The solar cell is an example of the success of physics because it relies on the quantum physics of semiconductors to generate electricity.
Wind power complements solar power because wind speeds are higher at night, when solar power cannot be generated. Statistical physics can help us better understand the dynamics of air turbulence in the presence of multiple wind turbines, such as in an offshore wind farm, thereby optimizing their operation and power generation efficiency.
Finally, Marston turned to the question of whether we can repair our climate. In direct air capture, CO2 is extracted from the atmosphere using a liquid solvent or a solid sorbent, and stored underground. In ocean alkalinity enhancement, alkaline material is used to increase the ocean’s capacity to capture CO2, forming stable bicarbonate ions. Even in these solutions, physics comes into play, such as in the analysis of open systems to account for ocean currents.
Yet, more than physics needs to be considered; it is far easier to prevent CO2 from entering the atmosphere than to remove it. Even promising solutions like replacing grasslands with redwoods to increase biological carbon sequestration carry hidden costs. These trees, being darker than grass, reduce the albedo and cancel some of the CO2 absorption benefits.
“As you’ve seen, this is more than just physics - it involves chemistry, engineering, biology, social science and understanding how human beings are behaving,” Marston concluded.
Marston believes that, unfortunately, physics cannot stop climate change, despite his wishes to the contrary.
“We have to change our behavior, what we value, in order to make a difference.”
