A SpaceX Starship (upper stage)/Super Heavy (booster) launch consumes an enormous amount of chemical energy—on the order of tens of petajoules.

The Raptor engines burn methane and oxygen in a staged-combustion cycle. SpaceX currently lists approximately 3,650 metric tons of propellant for Super Heavy and 1,600 tons for Starship, or about 5,250 tons total when fully loaded. This consists of approximately 1,140 tons of methane and 4,110 tons of liquid oxygen.

 How much energy is that?

Methane contains roughly 50 MJ/kg of chemical energy. The Starship/Super Heavy carries about 1.14 million kg of methane or approximately 57 petajoules (PJ) of chemical energy. That's about:

·       15.8 terawatt-hours (TWh) of chemical energy or 15.8 billion kWh

 The 57-PJ figure is equivalent to about 1.8 years of continuous electricity generation from a 1-GW power plant, a relatively large generating plant.

A striking comparison is the scale implied by SpaceX's proposed launch rate: At 145 Starship launches per year, the chemical energy released would total approximately 8.3 exajoules (EJ) per year—equivalent to the energy produced by a continuous 1-GW thermal power source operating for about 262 years.

 Where does that energy end up?

The energy released by the rocket is initially distributed among:

·       kinetic energy and potential energy of the exhaust and rocket

·       heat in the combustion products

·       atmospheric heating and turbulence

·       aerodynamic drag, gravitational losses

·       acoustic energy and other smaller energy pathways

Ultimately, most of the chemical energy released by the rocket will be degraded into low-grade thermal energy. Energy initially carried as rocket and exhaust kinetic energy, atmospheric motion, turbulence, and other forms is eventually dissipated as thermal energy within the Earth system, while some energy is ultimately radiated away from Earth as infrared radiation.

 A more consequential environmental effect of Starship launches isn't the direct heat from combustion. Starship's exhaust is primarily CO₂ and water vapor, with smaller amounts of CO, NOx, and particulate material. These combustion products—including water vapor and particles—are injected directly into the upper atmosphere, where their radiative and chemical effects can be substantially different from those of emissions released near the Earth's surface.

Sixth Mass Extinction

The likely Sixth Mass Extinction is fundamentally anthropogenic—that is, driven primarily by human activities. Unlike previous mass extinctions, which were caused by natural events such as asteroid impacts, massive volcanism, or major climatic shifts, the present biodiversity crisis is being produced by the rapid expansion and intensification of human activity. Population growth, agriculture, industrialization, resource extraction, urbanization, transportation, and global commerce have transformed ecosystems and accelerated the movement of species and pathogens around the planet. These activities collectively drive habitat loss, overexploitation, climate change, invasive species, and pollution— major drivers of contemporary biodiversity loss.

The probability that human activities will cause a sixth mass extinction cannot currently be expressed as a reliable percentage. However, the biological conditions that could produce one are already evident: extinction rates are elevated, populations are declining, and multiple human-driven pressures are acting simultaneously on ecosystems worldwide. Whether the present biodiversity crisis ultimately qualifies as a sixth mass extinction will depend largely on the magnitude and duration of future biodiversity losses.

Five Primary Drivers of the Sixth Mass Extinction:

Habitat Loss

• Destruction, conversion, and fragmentation of natural habitats
• Deforestation and agricultural expansion
• Urbanization, roads, mining, and infrastructure
• Coastal development
• Dams, river alteration, and other changes to freshwater systems
• Destruction of wetlands, coral reefs, mangroves, and seagrass beds

Overexploitation

• Overfishing
• Hunting and poaching
• Unsustainable logging
• Bycatch and other unintended mortality
• Removal of species faster than populations can reproduce

Climate Change

• Rising temperatures
• Changing precipitation patterns
• Increasing droughts, floods, fires, and other climatic extremes
• Ocean warming
• Sea-level rise
• Ocean acidification
• Shifts in the geographic ranges and timing of biological processes

Invasive Species

• Introduction of non-native species
• Predation and competition by invasive species
• Introduction of new parasites and pathogens
• Diseases transferred between wildlife, livestock, and humans
• Disruption of native ecological communities

Pollution

• Pesticides and herbicides
• Fertilizers and nutrient pollution
• Industrial chemicals and heavy metals
• Plastics and microplastics
• Oil and other petroleum products
• Pharmaceuticals and other emerging contaminants
• Air pollution and atmospheric deposition
• Light and noise pollution