This choropleth map displays annual CO2 emissions per country from 1850 to 2023, colored on a green-to-red gradient with a legend, year slider, and hover highlighting for specific country values. The visualization uses React state to manage selected years and moused-over countries, while D3’s `geoNaturalEarth1` projection, `geoPath`, and `geoGraticule` render the world map. A D3 `sliderBottom` control adjusts the year, triggering color updates derived from the country’s emission value relative to the global min/max range.