Last year, three billionaires – Richard Branson, Jeff Bezos and Elon Musk – launched the space tourism industry, with the three taking jaunts above earth.
What kind of greenhouse gas warming can we expect?
Exceptionally, for the actual launch of the rocket, the CO2 isn’t really the biggest problem here. It’s possible to use zero-carbon rocket fuel – NASA has been using liquid hydrogen for decades, and Jeff Bezos’ rocket used it too. But commercial hydrogen is made very carbon-intensive, although it is possible to make it emission-free.
SpaceX’s rockets, on the other hand, have kerosene and methane fuels, while Virgin Galactic’s Richard Branson has also zoomed in on carbon-based fuel.
While some of these fuels emit CO2, all cause other atmospheric problems. The biggest problem is ozone depletion, which can heat up the Earth and damage the ozone layer. Soot, carbon dioxide, water vapor and nitrogen oxides emitted by rockets also have a warming effect.
This is aggravated by the altitude at which the gases are emitted – a recent preprint (not peer-reviewed) suggests that 0.22% of upper stratospheric ozone could be lost after three years of space tourism, which could “significantly offset” the progress made by the Montreal Protocol.
The preprint also suggests that black carbon (soot) in the upper atmosphere from rocket launches could be 500 times warmer than soot emitted at ground level, due to its heat-absorbing behavior in the upper atmosphere.
It is therefore difficult to disentangle the emissions from rocket launches. We need more research before we can be truly definitive, although we know it’s not great. Basically, one researcher has suggested that per person, one space tourism flight is 50 to 100 times worse for the atmosphere than a long-haul plane flight.
But the proto-greenhouse gases in the rocket tank are only part of the picture. It is worth having a wider look.
We typically think of carbon emissions in three categories, or “scopes.” Scope 1 emissions are emissions that are directly produced by a company, jurisdiction, or other type of organization.
In the case of SpaceX, scope 1 emissions are emissions from rocket fuel, rocket transportation and SpaceX employees, and any fuel burned during testing and construction.
Scope 2 emissions are caused by a company’s or jurisdiction’s energy consumption. SpaceX’s electricity consumption, from office lighting to rocket manufacturing, counts for this.
Scope 3 emissions are caused by a company’s activity in the wider economy. A computer used by a SpaceX employee would have Scope 3 emissions associated with its manufacture and transportation, along with all other materials, tools, and services purchased by the company. This means that Scope 3 emissions are generally much larger and more difficult to count than Scope 1 or 2 emissions.
When countries and companies talk about reducing emissions, they usually focus on Scope 1 and 2 emissions. But Microsoft is plan to be carbon negative in Scope 1, 2 and 3 emissions by 2030, and the Australian Capital Territory calculated and also aims to reduce its Scope 3 emissions.
Microsoft has nearly 20 times as many employees globally as SpaceX (more than 180,000 versus around 10,000), and the ACT has more than twice as much citizens than that. If a nation’s capital and a global tech giant can dig deep enough into their complexities to count scope 3 emissions, a literal rocket science enterprise should be able to as well.
But SpaceX does not publish its shows widely. Tesla, Inc., one of Elon Musk’s other businesses, is also surprisingly opaque about the emissions needed to build its electric cars – a topic that other electric car makers have been much more open about. And Musk himself doesn’t seem particularly interested in solving this problem. In fact, he recently tweeted that corporate environmental and social governance – a common method of reporting and addressing environmental impacts – was “the devil incarnate”.
The other thing to note, however, is that while many of us find billionaire space tourism boring, we get a range of other benefits from these rocket launches. Earth monitoring satellites are the clearest example of this – providing us with much of the very data we use to track climate change.
According to the Australian Space Agency, other benefits include massive technological innovations, communication technologies and scientific exploration.
Whether we like it or not, space tourism is now part of this picture.
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