This heatmap shows CO₂ emissions per capita across 50 countries and 8 years, with row ordering toggleable between alphabetical and by row mean. Missing data appears as gray cells, while color intensity uses a sequential YlOrRd scale. Built with D3 v7 in SVG, it uses `d3.scaleBand` for row and column positioning, `d3.scaleSequential` for color mapping, and `d3.rollup` for aggregate calculations, with data loaded from a CSV file.