Climate change is already manifesting its effects on Earth, but soon its impact will extend to the space surrounding our planet, as suggested by a recent study.
Researchers from the Massachusetts Institute of Technology have calculated that ongoing global warming, caused by the burning of fossil fuels, might significantly constrict the available space for satellites in low Earth orbit. This reduction is anticipated to range from one-third to 82% by the century’s end, contingent upon the volume of carbon emissions released into the atmosphere. This scenario arises because the accumulation of debris will increase, while natural mechanisms that typically maintain cleanliness in space become less effective due to climate change.
The greenhouse effect, which warms the Earth’s lower atmosphere, concurrently cools the upper atmosphere where the boundary of space begins and satellites operate. The cooling effect decreases the density of the upper atmosphere, thereby diminishing the drag on countless fragments of human-generated debris and satellites.
Normally, this atmospheric drag draws space debris back towards Earth, where it burns up upon re-entry. However, with a cooler and less dense upper atmosphere, this self-cleaning process diminishes. Consequently, space becomes increasingly congested with debris, as detailed in a study published in Nature Sustainability.
“We depend on the atmosphere to clean up our debris. There’s no other viable method to eliminate it,” stated Will Parker, leading the research at MIT. “It’s waste. It’s trash. And the pieces are innumerable.”
Currently, there are millions of debris pieces measuring about 3 millimeters or larger orbiting the Earth. These can cause impacts with the energy comparable to bullets. According to data from The Aerospace Corporation, there are also numerous pieces of space junk the size of plums that possess the collision energy of a crashing bus. This debris includes fragments from previous space collisions and segments of rockets, much of which is too minuscule to track effectively.
As of now, 11,905 satellites are orbiting Earth, with 7,356 within low Earth orbit, based on information from Orbiting Now. Satellites are indispensable for activities such as communication, navigation, weather prediction, and monitoring both environmental and national security concerns.
“There was a notion that space is vast. This perception led to a somewhat lax attitude towards maintaining space environmental stewardship because of the perceived vastness,” Parker explained.
In 2009, the collision of two satellites produced thousands of debris fragments. Recent NASA findings also indicate a measurable decrease in drag, highlighting the significance of climate change’s role in orbital sustainability, Parker pointed out.
The density at an altitude of 250 miles (400 kilometers) above Earth is decreasing by approximately 2% per decade, a trend projected to worsen as greenhouse gas emissions continue. Ingrid Cnossen, a space weather expert at the British Antarctic Survey, not involved in the study, reinforced this viewpoint. Cnossen remarked that the new study seemed entirely sensible, emphasizing the necessity for scientists to recognize climate change’s implications for orbit to determine measures ensuring sustainable long-term use of space.