This choropleth map visualizes global CO2 emissions by country from 1850 to 2023, with darker reds representing higher emission values. A slider lets users scrub through years, updating country fill colors dynamically. The visualization uses React for state management, D3’s `geoNaturalEarth1` projection with `geoPath` for rendering world geography, and `sliderBottom` from `d3-simple-slider` for the year control. Data comes from a CSV subset of the Our World in Data CO2 dataset, with countries lacking data shown using a diagonal slash pattern.