CO2 gas turns Earth orbit into junkyard

Greenhouse gases are not only destroying our world they are also making space increasingly unsafe, causing a ring of debris to accumulate around the Earth, researchers have warned.

Scientists at Southampton University will present a paper at the Fourth European Conference on Space Debris next week predicting that within a couple of centuries it could become impossible to launch a satellite or spacecraft into orbit without a piece of fast-flying debris hitting it and exploding.

Hugh Lewis, the lecturer in aerospace engineering at Southampton who led the research, said: "We are only now beginning to understand the impact that polluting the atmosphere is having on space."

He added: "If the goal is to extend our manned exploration of the solar system then just getting out of the Earth's orbit could be a problem. You can see how vulnerable we are."

The research shows that rising levels of the greenhouse gas CO2 are contributing to a cooling and a decrease in density of the highest part of the atmosphere, known as the thermosphere.

This prevents satellites from burning up within their predicted lifetimes, meaning that the number of objects in space will continue to rise. With many objects - including discarded rockets and fragments from previous explosions - travelling very fast through space, the number of collisions will continue to increase. Each collision sends yet more fragments into orbit, creating a "collision cascade" effect.

A piece of debris bigger than 1cm is capable of causing the total destruction of any object that it hits at high speed.

According to Dr Lewis's initial predictions, between 200km and 2,000km above the Earth the amount of debris of this size will increase by 30 per cent over the next 30 years due to rising CO2 levels.

He explained that this could have major implications. Manned space travel could become too dangerous, and things we take for granted, such as using satellites to monitor the weather, could also be impossible.

Dr Lewis said: "At some altitudes you couldn't operate a satellite because it would be only days before something crashed into it and destroyed it."

But he stressed that this doom scenario would probably never happen as all space-faring nations were now treating the space debris problem very seriously.

His research will inform the work of the Inter-Agency Space Debris Co-ordination Committee, of which he is a member.