Towards a Sustainable Future

Co-author: Yared Mekbib, Shirley Tsai

Carbon dioxide (CO2 ), methane (CH4), and nitrous oxide (N2O) are the main contributors to climate change. Since the Industrial Era, humans have relied on fossil fuels to generate energy. However, the demand for economic growth has continued to increase, creating more needs for fossil fuel combustion and leading to an unprecedented amount of CO2 , CH4 and N2O in the atmosphere (Change, 2007). As greenhouse gases rise, global temperature also increases. As shown in figure 1, compared to 1880s to 1950s, 1960s to 2020s stray further away from the long-term temperature average between 1901 to 2000 (Climate at a Glance, 2021). Global temperature rises 1 to 1.2℃ since 1850. 1℃ may sound insignificant, but the small increase in temperature can lead to a wide range of environmental and health impacts such as extreme weather, loss of biodiversity, desperation, injuries during natural disasters, and so on (Rossati, 2017). Since CO2 is the main contributor to climate change, we will focus on CO2. Supplemented with real data and visualizations, this article will explain the impact of CO2 emissions so that you can be aware of the problem and take small actions to reduce CO2 emissions (Kosara & Mackinlay, 2013).

Figure 1: Annual temperature relative to the average temperature in 1901–2000

Moreover, treating the 1℃ temperature increases as one number conceals the large variation in global warming around the world. As figure 2 suggests, the top 10 countries with the highest CO2 emissions are all located in the northern hemisphere. Figure 3 shows that temperature increases drastically in the northern hemisphere as well. It’s important to note that water has a higher specific heat, so temperature change in land areas would be more obvious. Temperature over land has increased twice as much as the ocean and the northern hemisphere has more land mass than the southern hemisphere (Berkeley Earth, 2020). However, the high CO2 emitters are likely the main contributors to the great difference between the northern and southern hemispheres. Furthermore, high latitude areas experience the most drastic temperature change, so they are impacted the most among all regions.

Figure 2: Top 10 countries with the highest CO2 emissions
Figure 3: Temperatures in 2019 relative to the average temperature in 1951–1980 (Berkeley Earth, 2021)

After understanding the impact of global warming, we would like to know whether it is possible to reduce greenhouse gas emissions. According to the Kaya Identity, population, GDP per capita, energy density and carbon density determine total CO2 emissions (Kaya & Yokoburi, 1997). We found that the worldwide trends for GDP and CO2 emissions match each other, and figure 5 shows that GDP is increasing dramatically for every region, except Africa. The red treemap in figure 6 presents a basic understanding of the biggest, wealthiest, CO2 emitters. The bigger the box, the more emissions have been released and the darker the box, the higher the GDP of the country. From here we can determine that the biggest CO2 emitters are often the wealthiest countries. China, the United States, Germany, India, Japan, and Russia are some of the highest GDP countries who are also the top C02 emitters worldwide. As discussed previously, worldwide levels of C02 have increased from 25 billion to 32 billion metric tons in 2000–2011. The critical question is, “Is there any country that can reduce their CO2 emissions in a timely manner that still drives their growth in GDP?” Some countries like Singapore and Switzerland have shown that it’s possible (figure 7). All nations worldwide should switch to more sustainable, eco-friendly forms of energy or risk destroying the planet.

Figure 4: Trend of CO2 emissions and GDP in 2000–2010
Figure 5: Each region’s GDP trend
Figure 6: Top CO2 emitters and their GDP. The amount of emissions is represented by size.
Figure 7: Singapore’s GDP and CO2 emission trend

Internet Usage, Mobile Phone Usage, and Changing Energy Consumption

Digital connectivity, or the extent to which a population has access to the internet and mobile devices, also plays an important role in influencing a country’s energy consumption. We used a line chart to look at the trends of mobile phone and internet usage worldwide (Figure 8).

Figure 8: On average, mobile phone usage expanded at a higher rate than internet usage worldwide. Link to interactive visualization.

Notice how mobile phone usage expands at a higher rate than internet usage worldwide. This trend of mobile phones growing much faster than the internet is especially evident in developing countries, as mobile phones are important for development in areas which lack an established fixed-line infrastructure (James & Versteeg, 2007). Now, how do these trends relate with energy consumption?

To visualize the relationship between internet usage, mobile phone usage, and energy consumption, we created two scatterplots (Figure 8). Both graphs share the same y-axis, Energy Consumption in kg of oil equivalent per capita, while the x-axes show the proportion of internet usage and mobile phone usage in a country. Each colored point represents a single country from one year ranging from 2000–2011. Making these graphs interactive was important to allow users to manipulate the view of the scatterplots and filter the relevant information (Heer & Shneiderman, 2012). Moreover, the scatterplots are animated to provide a better view of how these proportions have changed over the years. Also note that the more opaque a point is, the more recent the year it corresponds to.

Figure 9: Increases in internet and mobile phone usage correspond with an increase in energy consumption in many countries, like India. Link to interactive visualization.
Figure 10: High-income countries like Denmark actually had reductions in energy consumption after some time.

We found that in many countries worldwide, increases in internet usage and mobile phone usage often corresponded with an increase in energy consumption. This occurred mainly in countries with developing economies, such as India, that began the time period with low rates (<1%) of internet and mobile phone usage (Figure 9). The increase in energy usage makes sense, since a population having greater access to phones and the internet likely means that there is also greater access to electricity. In contrast, some developed countries with high GDPs and relatively higher initial rates of internet and mobile usage (>35%), such as Denmark, actually began to reduce their energy usage after reaching a certain threshold of internet and phone usage (Figure 10).

The fact that more people worldwide are gaining access to electricity, phones and the internet is undoubtedly a positive development. However, because this likely means that more energy will be used, we need to continue striving towards greener forms of energy production, such as renewables.

Renewable Energy Solutions

To address this issue, we decided to look into what forms of renewable energy are most efficient. What are the most efficient and scalable technologies that will generate enough resources to limit C02 emissions? To investigate, the team decided to explore the countries with the highest renewable energy per capita. We saw this as an accurate metric, because it’s simple to evaluate which countries are the most sustainable per person.

Figure 11: Share of renewable energy worldwide

If we look at the treemap above, we can visualize the countries with the highest share of renewable energies. The top ten most sustainable countries are Norway, Iceland, New Zealand, Brazil, Sweden, Switzerland, Austria, Canada, Colombia, and Peru. This is actually quite an interesting statistic, because the most sustainable countries are not extraordinarily wealthy like China and the United States.

Figure 11: GDP amongst the most sustainable countries (2015)

If we look at the metric above, which lists the highest GDP amongst the most sustainable countries, we observe that Brazil, Canada, and Sweden are the wealthiest countries with 3.1 trillion, 1.5 trillion, and 600 billion GDP. These countries don’t even come close to the wealth of the United States and India, despite having less C02 emissions per capita. Although this is a bit worrying, as our world superpowers aren’t practicing sustainability, there is still a brighter future on the horizon. If countries with lower GDPs and less development can have such vast sources of renewable energy, why can’t the rest of the world? In order to figure out which technologies are best set up to scale, we looked at all sustainable countries and analyzed the amount of hydroelectric, solar, wind, and other renewable sources that make up their reserves.

Figure 12: Renewable energy breakdown via technology

If we look at the visualization above, we can gain a larger understanding of the most efficient, renewable, technologies in these sustainable countries. Within this visualization, vertical 2D positions were used to encode the quantitative value of the renewable technologies. We did this because it proved to communicate and compare with quantitative values extremely quickly (Few, 2019). This allowed us to determine the most effective renewable energy.

Hydroelectric energy is typically the accepted renewable energy source, as it covers the majority of renewable energy in all the most sustainable countries. The other two types are a mix between Wind energy and Other renewable energy (biomass, geothermal, etc). This is an extremely powerful visualization as it shows a bright future for renewable energy and sustainability. Third-world countries like Colombia, Brazil, and Peru are all very promising signs of lower GDP, developing nations establishing their own sustainable future. With these countries' development to grow aggressively over the coming years, hydroelectric and wind farms are the most scalable technology for the future.


Major changes need to be made globally to address the issue of climate change. As energy usage continues to grow in emerging economies, placing more emphasis on renewable energy sources is an important step towards a more sustainable future.


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