This document provides an overview of module 4 on climate change mitigation. It begins by explaining key concepts such as mitigation, low carbon development and greenhouse gases. It then discusses the need for global mitigation to limit warming to 2°C and outlines strategic frameworks like LEDS and NAMAs to support mitigation. Sections are dedicated to sectors with high mitigation potential including energy, transport, buildings, industry, agriculture, forestry and waste. Case studies from countries illustrate successful mitigation options and initiatives.