200 — Sustainability¶

This chapter introduces system-level thinking about climate impact, focusing on how emissions translate into long-term environmental consequences.

Rather than starting from complex Earth System Models, we use intentionally simplified climate models to make the causal structure explicit: emissions → concentrations → radiative forcing → temperature response.

The objective is not prediction, but mechanistic understanding.

Why this matters for aircraft propulsion¶

In sustainable aircraft propulsion, engineering decisions often reduce to:

fuel choice,
efficiency improvements,
operational changes.

All of these ultimately act through emissions.

To evaluate whether a technological option is meaningful in a climate context, engineers must understand:

why CO₂ accumulates,
why temperature responds slowly,
why short-term reductions do not immediately reverse warming.

This chapter provides that foundation.

Exercises in this chapter¶

Simple climate model (0-D)¶

A guided Jupyter notebook implementing a minimal climate–carbon model:

one-box atmospheric CO₂
zero-dimensional energy balance
explicit numerical integration

📓 Exercise notebook:
Simple climate model →

Learning outcomes¶

After completing this chapter, you should be able to:

Explain the difference between emissions, concentrations, forcing, and temperature
Describe why net-zero does not mean instant temperature stabilization
Identify the key time scales governing climate response
Critically assess claims such as “this technology reduces temperature by X°C”

These skills will be reused later when discussing:

Sustainable Aviation Fuels
Hydrogen
Non-CO₂ effects
Scenario building and uncertainty