Rocket Launches Leave Air Pollutant in Earth’s Stratosphere; NOAA Warns About Its Effects on Ozone Layer

In previous years, space travel has become a booming industry as more nations send rockets and satellites to different regions of space. A new study, however, reminds us that this scientific progress may come at a price.

Rocket-Fueled Space Pollution

The National Oceanic and Atmospheric Administration (NOAA) investigation suggests that the region of the atmosphere seven miles above the surface of the Earth could be polluted by space debris. These include a variety of metals from rockets and satellites, which have been vaporized by the heat when they re-entered our planet.

The study focused on a plausible 10Gg (10,000 metric tons) annual black carbon emission and its effects on the stratosphere. Led by research scientist Christopher Maloney from the Cooperative Institute for Research in Environmental Sciences (CIRES), the experts modeled the climate response of the stratosphere to potential emissions of black carbon from rockets that burn kerosene fuel.

A heavy launcher that uses a kerosene-fueled engine emits ten tons of black carbon into the stratosphere for every launch. The current annual emissions from space travel are about 1 Gg (1,000 metric tons) per year, and Maloney believes that a 10 Gg-per-year emission can be reached by 2040 if their projections come true.

Before this study, it was previously thought that only chlorinated solid-fueled rockets cause ozone loss. However, the research team concluded that the scale of ozone depletion from high black carbon-emitting kerosene rockets is comparable to the ozone loss from solid-fueled rockets that release chlorine gas.

The researchers also assume that in the coming decade, even submicron aerosols released during increased re-entry by defunct satellites could also enter the atmosphere and cause changes to the stratosphere.

Effects of Man-Made Space Debris

In recent years, space launch rates have increased to more than triple, and accelerated growth is expected in the coming decades. The tenfold increase in the amount of soot ejected into the stratosphere every year could lead to an annual temperature increase in that layer of 1 to 4 degrees Fahrenheit (0.5 to 2 degrees Celsius).

The 10 Gg-per-year emission poleward of 30 degrees North can lead to a year-round total column ozone loss in the stratosphere. The most severe loss could happen at the northernmost latitudes during the summer season in the Northern Hemisphere. Warmer temperatures in this layer of the atmosphere can degrade the protective ozone layer, which protects the Earth from the harmful UV radiation from the Sun. Without ozone, humans are more at risk of skin cancer and changes in the immune system. Additional climate impacts can also result from changes in the wind patterns.

As described by Maloney, heating due to black carbon can cause shifts in the dynamics of the stratosphere. Aside from this, the black carbon can also trigger changes to the upper atmospheric jet streams of our planet. These zonal wind features are important in controlling large-scale weather patterns in our lower atmosphere.

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