Our presentation focuses on greenhouse gas emissions and energy consumption data for various countries in 2018, sourced from Our World in Data. We selected 2018 as our reference year because it predates the disruptive impact of the pandemic on global industries and energy consumption patterns, providing a baseline that more accurately reflects typical energy use and emissions without the extraordinary influences of the pandemic's peak years. This choice ensures a more consistent analysis of energy trends and environmental impact across nations.
Our visualization explores the link between energy consumption and greenhouse gas emissions on a global scale. We implemented a divergent color scale ranging from light yellow to orange-brown to illustrate the variance in emissions across countries, where deeper hues signify higher emissions, offering a clear and immediate visual cue of each country's emission levels. We chose to use sky blue to represent the oceans as yellow and blue are on opposite sides of the color wheel, which creates a high contrast that can make elements in a graph more distinguishable. This is particularly helpful for viewers with color vision deficiency as these colors are usually discernible. For countries with no data for greenhouse gas emissions, we chose light grey for aesthetic appeal. The zoom behavior allows users to focus on a specific country on the map, which is important for a global map where countries can be quite small and hard to interact with. When the user hovers the mouse over a particular country, the color will become dark blue to inform the user of the selected region. Moreover, we have included a color scale on the left side to offer the audience a clearer understanding of the varying levels of greenhouse gas emissions depicted in this global map.
Countries on the map can be clicked to generate pie charts, creating an interactive exploratory experience where users can delve into the specifics of each country's energy consumption. After the user clicks on a region, a hollow pie chart will appear on the right-hand side, revealing the breakdown of each country's energy mix. Interactive features enhance user engagement: hovering over a country transforms its color to a striking dark blue while clicking reveals a zoomed-in, blurred view for focus. Hovering over a specific energy type will display the corresponding consumption data within the chart's center which also guides the user to hover over for more information. Specific colors are assigned to different energy sources in the pie chart (case switch in the drawPieChart function), which helps users quickly differentiate between them and connect them with the colors of the sources in real life. Beneath the pie chart, there is also a legend specifying the sources and their corresponding colors.
Complementing this, a horizontal bar chart on the left ranks the country's emissions, providing comparative context at a glance. A reset button with the text “Return to World Map” allows users to return to the initial view of the world map. When the user clicks on a country, there will be a sorted horizontal bar chart appearing on the left of the pie chart showing the CO2 emissions rankings of neighboring countries also measured in megatonnes of CO₂. For a clear visual distinction, the bar corresponding to the chosen country is highlighted in red, facilitating an immediate and effective comparative analysis. By providing the bar chart and pie chart side by side, users are able to objectively compare and draw conclusions about whether there is a relationship between energy composition and CO2 emissions. For example, China has the highest CO2 emissions of 4117.87 MtCO2e and the majority of energy usage in 2018 is coal.
In our initial design, we presented the energy mix of each country through standard pie charts, with textual data displayed beneath. To create a more engaging and interactive visualization, we later optimized this by embedding the text information within the pie chart's center, making it more visually compelling and readable. We also considered creating sorted bar charts to show the proportion of electricity generated from various energy sources by country. However, we recognized that this might divert from our core objective: to explore the connection between energy consumption and greenhouse gas emissions. Thus, we decided to further our analysis and created bar charts that rank each country's emissions.
Xuecheng worked on the world map and the pie charts. Yihuan and Jiayi worked on the bar chart and the write-up. We roughly spent 20 people-hours developing the application. The pie chart and bar chart took most of the time, including finding good colors to better illustrate the specific components of energy consumption and standardizing the bar chart. Additionally, we take more time to align the bottom of the two plots to make them more structured.