This D3.js bar chart visualizes CO2 emissions per capita across countries for a selected year, with three interactive button controls that reorder the bars alphabetically, by value, or by a derived attribute. The visualization uses `d3.scaleBand` and `d3.scaleLinear` to map categorical and quantitative data, with axes created via `d3.axisBottom` and `d3.axisLeft`. The chart loads data from a CSV file containing country-level attributes such as population, GDP, and renewable energy percentages, and renders as SVG with hover effects on individual bars.