This visualization displays the long-term trend of global CO₂ concentration in parts per million, plotted as a zoomable bar chart that highlights historical fluctuations from over 800,000 years ago to the near present. The chart uses the D3 library (v6) to load CSV data, parse it with `d3.csvParse`, and filter for the World entity before mapping the year and concentration values. Bars are rendered in an SVG via `d3.create`, with zooming enabled to allow users to inspect dense early periods or recent dramatic increases. The data comes from the provided `co2-concentration-long-term.csv` file, processed entirely client-side.