Giant balloon to be launched to test climate fix hope

By Leila Battison
Science reporter, Bradford

  • Published

A huge helium-filled balloon attached to a 1km length of hosepipe is to be launched next month to help investigate the feasibility of climate engineering.

One method involves pumping particles into the stratosphere, to mimic the short-term cooling effects of volcanic eruptions.

The balloon test next month will investigate the engineering challenges posed by such a project.

Representatives discussed the project at the Science Festival in Bradford.

Scientists from universities across the country, and Marshall Aerospace are working together on the SPICE project (Stratospheric Particle Injection for Climate Engineering), which will research this particular type of geo-engineering.

They are investigating the best kind of particle that can be put in the atmosphere, the best way to deliver it, and the potential effects this will have on the Earth's climate.

The launch next month will be the first of its kind in the UK, and by raising a balloon to a height of 1km, will test the feasibility of a much larger-scale project with particles being released at a height of 20km.

October Launch

Tackling climate change with atmospheric particles, or aerosols, is a method inspired by large volcanic eruptions, like the 1991 eruption of Mount Pinatubo in the Philippines.

The eruption ejected at least five cubic kilometres of ash and gas, which rapidly spread around the globe and, in the two years following the eruption, decreased the average global temperature by 0.5 degree Celsius.

This was because the aerosols released by the volcano reflected back the Sun's radiation and heat before it reached the atmosphere, keeping the planet cooler.

A global geo-engineering project would see reflective particles artificially released into the atmosphere to create this cooling effect.

The SPICE project has received £1.6 million to investigate all aspects of such a technique, and their field test next month is the first of several proposed launches to directly observe the high-altitude delivery mechanism of reflective particles.

The 20m-long balloon will be released from an abandoned airfield in Sculthorpe in northern Norfolk during October when weather conditions are suitable.

It will be tethered to the ground with an 800m length of reinforced hosepipe which will stretch to allow the balloon to rise to an altitude of 1km.

A domestic pressure washer will provide enough force to pump water from the ground to the top of the hosepipe, and spray it out at a rate of around 100 litres per hour.

With this set-up, the researchers hope to observe how the balloon and the pipe react to high winds, the practicalities of its launch and retrieval, and much more.

In particular, they will be collecting information that can be scaled up to model the 20km altitude that would be needed to eject particles into higher layers of the atmosphere, and predict the reactions of the balloon setup in such a scenario.

Dr Matt Watson of the University of Bristol stressed that we are "decades away" from launching a functional 20km balloon. He said that, given that the trials prove that this kind of geo-engineering is possible, "just because we can do it doesn't mean we have the right to".

'Stimulate Public Debate'

The method of injecting aerosols is just one of many potential geo-engineering techniques that have been proposed as a way of countering global warming.

But the SPICE team point out that this kind of intervention will not change the amount of CO2 in the atmosphere; just reduce the warming caused by the greenhouse gases.

They predict that 10 or 20 giant balloons at 20km altitude could release enough particles into the atmosphere to reduce the global temperature by around 2 degrees.

This temperature decrease would not be uniform across the globe; equatorial regions would see a more pronounced temperature drop, while the poles would be relatively unaffected.

Reasons for this regional variation are still not fully understood, and the difficulties in predicting the reaction of the climate to geo-engineering have bred concerns for some.

Public forums carried out by Cardiff University and the Natural Environment Research Council (Nerc) have highlighted that very few people were unconditionally positive about the concept of artificially engineering Earth's climate.

The SPICE project, in particular, has prompted climate pressure group ETC to write an open letter to the UK government, requesting them to halt this latest field test.

"There has been no decision to go forward with 'solar radiation management' and therefore there is no need to test the hardware designed to implement it." said Pat Mooney, executive director of ETC Group.

Dr Matt Watson said however, that "a belief in research does not mean advocacy", and that he hopes the research carried out as part of the three-year SPICE project will "constrain the uncertainty surrounding the methods, and stimulate public debate".

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