Can Earth’s reflection help cool the planet?

Could the Earth’s ability to reflect sunlight — known as surface albedo — help compensate global warming? That is the question behind a study published recently in Nature, co-authored by Aolin Jia, a postdoctoral researcher within the Environmental Sensing and Modelling unit at the Luxembourg Institute of Science and Technology (LIST). The study reveals that as human activity and climate change have altered landscapes worldwide, they have also increased the planet’s reflectivity — leading to a small but measurable cooling effect.

A subtle cooling effect with global impact

“To understand albedo, imagine a hot day,” explains Jia. “If you had to choose between wearing a white T-shirt or a black one, you'd likely pick the white. That’s because white reflects more sunlight and keeps you cooler, while black absorbs more heat, making you feel warmer. This basic concept illustrates what scientists call albedo—the proportion of solar energy reflected by a surface.”

When sunlight reaches the Earth, some of it is reflected back into space by land, water, or snow, while the rest is absorbed, contributing to warming. “Greenhouse gases like carbon dioxide trap part of that energy in the atmosphere, which intensifies the greenhouse effect. While the role of greenhouse gases is well documented, the changing behaviour of Earth's surface reflectivity—its albedo—has been less well understood,” he says.
Albedo varies significantly across different land cover types. Forests, for example, appear dark from space and absorb much of the incoming solar radiation. Deserts and snow-covered areas, on the other hand, are much brighter and reflect a larger share of sunlight. Using two decades of satellite data, the study has now quantified how land use, land cover changes, and snow dynamics have altered the Earth’s surface albedo from 2001 to 2020.

Jia says, “We have found that in snow-covered regions, albedo has decreased significantly due to reduced snow cover—a trend consistent with a warming climate. However, in snow-free areas, albedo has actually increased. This increase, though modest, is statistically significant and results in more solar energy being reflected back into space.”

The study has found that albedo changes have led to a global cooling of about −0.142 W/m², with snow-free regions alone contributing −0.164 W/m². And that this cooling effect is equivalent to nearly 60% of the warming caused by global CO₂ emissions between 2011 and 2019.

Not just about deforestation and urbanization

Another insight from the paper was that most of the albedo-driven cooling did not come from places undergoing massive changes like deforestation or urban expansion. Instead, it came from areas that did not see any major land use changes.

“Even in regions where we don’t see big conversions, the surface is still changing,” Jia notes. “For example, changes in vegetation fraction, phenology, soil moisture, or drought conditions can all affect how reflective the land is.”

These “non-conversion” regions showed to have a radiative impact 3.9 to 8.1 times greater than areas where the land was actively converted.

Can this be a response to global warming?

“Every coin has two sides,” Jia cautions. “While the increase in albedo can partially mitigate greenhouse warming, the problem is greenhouse gas concentration is still rising significantly. So, albedo feedback, from deforestation for example, cannot completely compensate warming and cannot be seen as a solution.”

The real significance of the study, Jia emphasizes, lies in the need to factor these albedo changes more explicitly into climate models and mitigation strategies and not just focus on greenhouse gas concentrations. “Albedo changes clearly have a measurable impact on the Earth’s energy balance, and they shouldn’t be overlooked.”

Second, the study highlights the importance of understanding feedback mechanisms from land use and land cover changes, such as deforestation. “Most studies look at how energy drives processes like evaporation and transpiration,” Jia notes. “But the reverse is also true—those processes can affect the energy budget, including albedo. That feedback loop is often ignored, but it matters.”

Finally, he stresses that land-use decisions have broader implications than often acknowledged. “Changing forests into urban areas isn’t just bad for public health or biodiversity—it also alters how much solar energy is reflected or absorbed,” he says. “These surface changes play a role in climate dynamics, and we need to treat them with the same seriousness as emissions.”