Climate change does not only affect weather patterns and sea levels. It also alters the environment of space where satellites operate. Greenhouse gas emissions are causing the upper atmosphere to shrink. This contraction reduces atmospheric drag. This allows debris to remain in orbit longer and increases the risk of collisions. Scientists now warn that the long-term impact of greenhouse gas emissions may reduce the number of satellites that can safely operate in low Earth orbit.
Climate Change and Space Traffic Crisis: Greenhouse Gases Are Making Space More Dangerous for Low Earth Orbit Satellites
Background
The thermosphere naturally expands and contracts every 11 years due to solar cycles. However, a considerable level of evidence suggests that recent contractions have gotten stronger than expected, thus indicating a role for greenhouse gases. Aerospace engineers at the Department of Aeronautics and Astronautics of Massachusetts Institute of Technology conducted a study to examine the particular impact of greenhouse gas emissions on satellite sustainability.
Specifically, through a simulation, the researchers used projected carbon dioxide emissions from Shared Socioeconomic Pathways to evaluate the impact of satellite carrying capacity. They also introduced the instantaneous Kessler capacity metric to estimate the maximum number of satellites that can be supported without excessive debris. Their findings provide a clearer understanding of how climate change will affect satellite operations over the coming decades.
Findings
Results of the assessment, which are documented and discussed in a peer-reviewed article published in the journal Nature Sustainability on 10 March 2025, indicate that rising greenhouse gas emissions are altering the structure of the thermosphere and reducing its density. This change increases the longevity of space debris, leading to greater risks of satellite collisions. Specific findings include the following:
• The satellite carrying capacity of low Earth orbit could decline by 50 to 66 percent by the year 2100 if emissions continue to rise based on the simulation.
• Reduced atmospheric drag allows space debris to remain in orbit for extended periods. This increases the risk of collisions and creates a self-sustaining cycle of more debris.
• The number of satellites in low Earth orbit has increased significantly. There were more satellites launched in the past five years than in the previous six decades.
• Megaconstellations like the SpaceX Starlink network contribute to the rapid expansion of satellites. This increases the urgency of managing orbital sustainability.
Implications
Satellite technology is critical to global communications, navigation, weather forecasting, and financial transactions. However, the expansion of satellite networks must be carefully managed. If space becomes too crowded, the risk of debris accumulation and satellite collisions could make certain orbital regions unusable. This would affect businesses, governments, and research institutions that rely on satellite-based services.
Scientists emphasize that addressing greenhouse gas emissions is not just an environmental issue but also a necessity for maintaining space sustainability. Hence, without intervention, low Earth orbit could become an increasingly hazardous environment for new satellites, leading to higher costs and operational challenges for space missions.
Managing satellite operations in a shrinking thermosphere requires coordinated international efforts. Policymakers, space agencies, and private companies must consider long-term sustainability strategies, including limiting emissions and improving debris management. Future studies must continue to monitor atmospheric changes and their impact on space operations to prevent overcrowding and ensure the safe use of low Earth orbit for future generations.
FURTHER READING AND REFERENCE
- Parker, W. E., Brown, M. K., and Linares, R. 2025. “Greenhouse Gases Reduce the Satellite Carrying Capacity of Low Earth Orbit.” In Nature Sustainability. Springer Science and Business Media LLC. DOI: 1038/s41893-025-01512-0