A carbon footprint is a measure of the total greenhouse gas emissions (primarily carbon dioxide and methane) caused by an individual, community, event, organization, service, product, or nation. A greenhouse gas (GHG) is a gas that absorbs and emits thermal radiation, creating a “greenhouse effect” that traps heat near the Earth’s surface and ultimately warms the planet.
Greenhouse gases are important in maintaining the Earth’s habitable temperature. However, an overabundance of greenhouse gases in the atmosphere can disrupt Earth’s carbon cycle and accelerate global warming. This is the scenario unfolding at present, with the main contributor of greenhouse gases being emissions caused by excessive consumption of fossil fuels. When discussing emissions on a national or global scale, carbon footprint is typically expressed in units of CO2—typically metric tons (1,000 kg/2,205 lb = 1 t), million tons (1,000,000 t = 1 Mt) or gigatons (1 billion metric tons/1,000 Mt = 1 GT).
Reducing the Carbon Footprint
Generally, developed nations have higher carbon footprints and higher CO2 emissions per country. This is largely due to their more robust energy industries, which burn large amounts of fossil fuels to provide electricity, and a larger percentage of residents who own their own automobiles, which contribute greatly to emissions. Industries such as manufacturing and meat production are also noted contributors.
Nations can reduce their carbon footprint in many ways. Methods often employed include generating electricity from renewable energy sources (solar, wind, hydroelectric) instead of fossil fuels, improving energy efficiency, promoting biofuels in transportation, reducing CO2 emissions from vehicles, recovering greenhouse gases such as methane from landfills and smokestacks, charging a carbon tax on industries that emit GHGs, and reversing deforestation.
Many countries have pledged to use these and other steps to become carbon neutral, which means they remove as much CO2 as they release. In fact, a few countries have managed to become carbon negative countries that remove even more CO2 from the air than they add to it. Individual citizens can also reduce their carbon footprint by choosing to walk, bike, carpool, or use public transportation instead of driving, using reusable containers or bottles instead of individual plastic ones, reducing overall electricity usage, and eating less red meat.
Carbon Footprint by Country
According to the European Union's Joint Research Centre, total global CO2 emissions increased from 34.1 GT in 2010 to 37.9 GT—an all-time high—in 2019. The COVID-19 pandemic and its related restrictions on travel and transportation triggered a decrease to 35.962 GT in 2020, but emissions are expected to resume increasing once 2021 totals become available. China is the largest emitter of CO2 in the world, with 11680 Mt (11.680 GT) of carbon dioxide emissions in 2020. This is just over 32% of the world’s total 2020 emissions. The United States released the second-highest amount of carbon emissions at 4.535 GT, or roughly 12.6% of the total global emissions.
Top 10 CO2-emitting countries in the world (Total CO2 in Mt) - EU JRC 2020
Country | 2020 CO2 Emissions |
|---|---|
| China | 11,680 |
| United States | 4,535 |
| India | 2,412 |
| Russia | 1,674 |
| Japan | 1,062 |
| Iran | 690 |
| Germany | 637 |
| South Korea | 621 |
| Saudi Arabia | 589 |
| Indonesia | 568 |
Total emissions, however, fall short of telling the full story. For example, sharp-eyed observers may notice that the top three emitters are also three of the most populous countries on Earth, so it stands to reason that their emissions would be higher than that of countries with a fraction as many residents. For a more accurate measure of whether a country's policies are succeeding or failing to reduce CO2 emissions, it is often helpful to examine not only total emissions, but also CO2 emissions per capita.
Top 15 Countries with the Highest CO2 Emissions per Capita (t) - EU JRC 2020
Country | 2020 Emissions Per Capita |
|---|---|
| Palau | 55.29 |
| Qatar | 35.64 |
| New Caledonia | 25.52 |
| Trinidad and Tobago | 21.97 |
| Bahrain | 21.6 |
| Kuwait | 20.91 |
| United Arab Emirates | 20.7 |
| Gibraltar | 20.55 |
| Brunei | 17.95 |
| Saudi Arabia | 16.96 |
By this measure, the U.S. has the thirteenth-highest per capita emissions at 13.68 tons, while Russia is 20th (11.64), Japan is 26th (8.39), China is 28th (8.20), and India is 110th with a mere 1.74 tons per capita. Meanwhile, a number of developing nations occupy the top spots, largely due to less-regulated energy, industry, and transportation industries.
