A responsive line chart visualizes mean greenhouse gas emissions per year, averaged across the dataset and colored by year. It uses d3.csv to load the data, d3.group and d3.mean for aggregation, and d3.line to generate paths. SVG axes, scales, and a legend are built with d3.scaleTime, d3.scaleLinear, and d3.axisBottom/Left. The source is an integrated CSV from a GitHub repository.