Climate change will keep space debris threatening Earth for longer, study finds

Climate change will increase the lifetime of space pollution, a new study has found.

Satellites will have a greater chance of colliding with debris due to the reduced density in the atmosphere, which has happened as a result of increasing carbon dioxide levels, according to new research from British Antarctic Survey.

This will reduce the drag on objects between 90- and 500-kilometres altitude –with ‘low Earth orbit’ is defined as any object in an altitude under 2000 kilometres. A collision could cause billions of dollars in damage, and in a worst-case-scenario, stop humans from exploring other worlds.

Using a simulation of the atmosphere up until the year 2070 Ingrid Cnossen, a NERC independent research fellow at the British Antarctic Survey, found that the middle and upper atmosphere has been cooling – leading to the decline in density.

Even if humans reduce their emissions, the average cooling and decline in the upper atmosphere’s density is twice as large as has been previously seen.

"The changes we saw between the climate in the upper atmosphere over the last 50 years and our predictions for the next 50 are a result of CO₂ emissions. It is increasingly important to understand and predict how climate change will impact these regions, particularly for the satellite industry and the policymakers who are involved with setting standards for that industry”, Dr Crossen said.

"Space debris is becoming a rapidly growing problem for satellite operators due to the risk of collisions, which the long-term decline in upper atmosphere density is making even worse. I hope this work will help to guide appropriate action to control the space pollution problem and ensure that the upper atmosphere remains a usable resource into the future."

The research has been published in the journal Geophysical Research Letters.

There are over 30,000 trackable debris pieces in low Earth orbit larger than 10 centimetres in diameter, and 1 million debris objects greater than 1 centimetre, according to the European Space Agency. There are approximately 5,000 active and defunct satellites in low Earth orbit, as of March 2021, and that number has increased by 50 per cent since 2019.

The FCC recently adopted a new rule that would require operators to deorbit satellites within five years of them ending their mission.

“Right now there are thousands of metric tons of orbital debris in the air above—and it is going to grow,” FCC chairwoman Jessica Rosenworcel said. “We need to address it. Because if we don’t, this space junk could constrain new opportunities.”

However, University of Southampton Professor of Astronautics Hugh Lewis has argued that while the new rule would reduce debris in higher altitudes, “we don’t see in these results is a significant reduction in close approaches or collisions at the altitudes currently being dominated by commercial space industry and human spaceflight”.

It has even been suggested that the problem will not be adequately addressed until there have been more disasters. Neither governments nor private companies have the inclination nor the technology to stop space debris, and that will only come when governments are willing to be more cooperative

“You have to make sure that other nation states are comfortable with this technology being in space and servicing these various other companies where it has a military use, in principle”, Adam Burrows, a professor of astrophysical sciences at Princeton University, told The Independent last month.

“How do you lower the political temperature enough? It requires negotiation. It requires a few more disasters. There have already been disasters to some degree. There haven’t been enough.”