This heatmap visualizes San Francisco municipal greenhouse gas emissions by commodity information across fiscal years 2020–2022, using color intensity to represent the total mtCO₂e per category per year. It reads emissions data from a CSV file, aggregates it with `d3.rollups` and `d3.sum`, and renders an SVG via `d3.scaleBand` for axes and `d3.scaleSequential` with an Orange-Red interpolator for the color gradient. Hovering a cell displays a tooltip with commodity, year, and formatted emissions value.