This example reproduces the Keeling Curve, showing the steady rise in atmospheric CO2 concentration from 1958 to the present, with the characteristic seasonal zigzag pattern. The line chart uses d3.line to render the data, with d3.scaleTime and d3.scaleLinear mapping dates and CO2 values. Data is loaded from a NOAA CSV file and parsed with d3.csvParse and d3.timeParse. The visualization is built with D3 v7, including custom axis labels and a responsive SVG that fills the viewport.