Explained: Is growing space tourism posing a risk to the climate?

The researchers state that routine launches by the rapidly growing space tourism industry “may undermine progress made by the Montreal Protocol in reversing ozone depletion.”

They argue that there is an urgent need for environmental regulation to reduce the climatic damage from this fast growing industry.

Space tourism industry

In the 20th century, the Soviet Union and United States were engaged in an intense competition to attain complete domination of spaceflight technologies. Today, it is private companies that are taking part in their very own commercial space race, initiated with Jeff Bezos and Richard Branson’s journeys to space in July 2021.

A segment of space travel, space tourism allows lay people to travel to space for recreational, leisure or business purposes. The aim is to make space more accessible to those people who are not astronauts and want to travel to space for non-scientific reasons.

Less than a year after Bezos and Branson’s escapades, The New York Times reports that global space tourism has been thriving, with various companies offering bookings for zero-pressure balloon trips for short flights, astronaut boot camps and simulated zero-gravity flights.

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According to the authors of the recent study published in Earth’s Future, “The space industry is one of the world’s fastest growing sectors”.

From $350 million in 2019, the industry is forecasted to grow to more than $1 trillion by 2040. With companies like Virgin Galactic, SpaceX and Blue Origin launching commercial space flights, space tourism has become, at least theoretically, a possibility for enthusiasts. Tickets remain tremendously expensive however, with tickets for Richard Branson’s Virgin Galactic beginning from a whopping $450,000.

What is the new study?

Researchers from University College London (UCL), the University of Cambridge and Massachusetts Institute of Technology (MIT) in their new study, claim that the burgeoning space tourism industry can have a far bigger cost on the environment.

They calculated their findings by compiling an inventory of the chemicals from all the 109 rocket launches and re-entries into the Earth’s atmosphere in 2019.

They also projected the growth of space tourism by corporations like Virgin Galactic, Blue Origin and SpaceX. These were then incorporated into a 3D model to examine the possible impact on the climate and the protective stratospheric ozone layer.

The number of rocket flights today is rather small when compared to the sheer size of the aircraft industry.

While in 2020, there were only 114 orbital launches in the world, more than 100,000 flights travel each day, as reported by The Guardian.

What are the study’s findings?

Unlike other sources of pollution, the study finds that environmental damage caused by rockets is far greater, as they emit gaseous and solid chemicals directly into the upper atmosphere.

The space tourism’s current growth trends also indicate a potential for the depletion of the ozone layer above the Arctic. This is because the pollutants from rocket fuel and heating caused by spacecraft returning to Earth, along with the debris caused by the flights are especially harmful to the ozone layer, University College London (UCL) stated in a press release.

What is of great concern is the black carbon (BC) soot that is emitted by rockets directly into the atmosphere. These soot particles have a far larger impact on the climate than all other sources of soot combined, as BC particles are almost 500 times more efficient at retaining heat.

The low figure of rocket launches, compared to the large scale air pollutant emissions caused by the massive aircraft industry, is at times invoked to downplay the environmental damage caused by rockets. Dr Eloise Marais, the co-author of the study argues that this comparison is incorrect.

“Soot particles from rocket launches have a much larger climate effect than aircraft and other Earth-bound sources, so there doesn’t need to be as many rocket launches as international flights to have a similar impact. What we really need now is a discussion amongst experts on the best strategy for regulating this rapidly growing industry.” she said in a press release.

The team of researchers showed that within only 3 years of additional space tourism launches, the rate of warming due to the released soot would more than double.

This is because of the use of kerosene by SpaceX launches and hybrid synthetic rubber fuels by Virgin Galactic.

Undermining Montreal Protocol

While the loss of ozone from current rocket launches is “small”, the researchers argue that in the likelihood of weekly or daily space tourism rocket launches, the recovery of the ozone layer caused by the Montreal Protocol could be undermined.

“The only part of the atmosphere showing strong ozone recovery post-Montreal Protocol is the upper stratosphere, and that is exactly where the impact of rocket emissions will hit hardest. We weren’t expecting to see ozone changes of this magnitude, threatening the progress of ozone recovery,” said the study’s co-author Dr Robert Ryan in a press release.

The Montreal Protocol is a landmark international treaty that was adopted in Montreal in 1987, and was aimed at protecting the Earth’s ozone layer by regulating the production and consumption of nearly 100 chemicals called ozone-depleting substances (ODS).

The treaty phases down the consumption and production of various ODS in a stepwise manner.

As per the Montreal Protocol, developing and developed countries have but equal and differentiated responsibilities, however all countries have to follow binding, time-targeted and measurable commitments.

Considered to be one of the most successful environmental interventions on the global scale, it is the first treaty to achieve universal ratification by all countries in the world.

The United Nations Environment Programme (UNEP) states that without this treaty, ozone depletion would have increased by more than ten times by 2050, as compared to current levels.

The recovery of ozone layer caused by the Montreal Protocol has been estimated to save around 2 million people each year from skin cancer. Between 1990-2010, the treaty led to a reduction of greenhouse gas emissions by an approximate 135 gigatons of CO2.