Worst Polluting Nations in the World Compared to Shipping & Aviation Industries

Transportation is the heaviest polluting sector in the United States and one of the largest polluters globally. Every day around the world, approximately 100,000 flights take off and land—equal to about 1.2 flights every second, according to the World Economic Forum. Additionally, more than 80% of all global trade is transported by shipping vessels, and at any given time, there are as many as 100,000 bulk carriers, container ships, and tankers at sea, according to MagicPort, a shipping industry data company. 

Not even accounting for overland transport, aviation and shipping generated 1.4 billion metric tonnes of greenhouse gas emissions in 2025 alone, or about 2.6% of all emissions worldwide. Despite a substantial dip in carbon pollution from aviation and shipping in 2020, the first year of the COVID-19 pandemic, the interconnected nature of the global economy appears to be driving up pollution from aerial and nautical transportation. In the last year alone, greenhouse gas emissions from aircraft and ocean vessels increased by 3.3%, and between 2015 and 2025, emissions spiked by nearly 13%. 

Notably, sea and air traffic’s carbon footprint exceeds that of most countries, generating more than double the volume of greenhouse gas emissions as Australia, and nearly four-times as much as the United Kingdom. Indeed, if international shipping and aviation were a sovereign country, it would rank among the world’s biggest polluters. 

Using data from the European Commission’s Emissions Database for Global Atmospheric Research, Climate Crisis 247 identified the world’s 10 worst polluters. We ranked all countries with available data on total greenhouse gas emissions in 2025, and, for comparison purposes, included international aviation and shipping as a discrete entity. Where applicable, population figures are 2025 estimates from the World Bank. All other supplemental data are from EDGAR.

10. Saudi Arabia

• Greenhouse gas emissions in 2025: 845.0 metric tonnes (1.6% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +1.3% (+10.6 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +11.9% (+90.0 million metric tons)
• Population in 2025: 36,973,555 (0.5% of global total)

9. Japan

• Greenhouse gas emissions in 2025: 1.1 metric tonnes (2.0% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): -1.4% (-15.5 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): -19.9% (-263.6 million metric tons)
• Population in 2025: 123,366,734 (1.5% of global total)

8. Iran

• Greenhouse gas emissions in 2025: 1.1 metric tonnes (2.1% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +1.7% (+18.8 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +40.2% (+320.9 million metric tons)
• Population in 2025: 92,417,681 (1.1% of global total)

7. Brazil

• Greenhouse gas emissions in 2025: 1.3 metric tonnes (2.4% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): -0.9% (-11.4 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +5.9% (+72.3 million metric tons)
• Population in 2025: 212,812,405 (2.6% of global total)

6. Indonesia

• Greenhouse gas emissions in 2025: 1.4 metric tonnes (2.5% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +1.2% (+16.1 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +53.6% (+474.4 million metric tons)
• Population in 2025: 285,721,236 (3.5% of global total)

5. International Aviation and Shipping

• Greenhouse gas emissions in 2025: 1.4 metric tonnes (2.6% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +3.3% (+44.9 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +12.8% (+157.8 million metric tons)
• Population in 2025: N/A

4. Russia

• Greenhouse gas emissions in 2025: 2.6 metric tonnes (4.8% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): -0.1% (-3.3 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +14.8% (+332.6 million metric tons)
• Population in 2025: 143,513,328 (1.7% of global total)

3. India

• Greenhouse gas emissions in 2025: 4.5 metric tonnes (8.3% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): -0.2% (-6.8 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +36.8% (+1.2 billion metric tons)
• Population in 2025: 1,463,865,525 (17.8% of global total)

2. United States

• Greenhouse gas emissions in 2025: 6.0 metric tonnes (11.1% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +2.2% (+131.5 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): -5.1% (-322.0 million metric tons)
• Population in 2025: 341,784,857 (4.2% of global total)

1. China

• Greenhouse gas emissions in 2025: 16.0 metric tonnes (29.5% of global total)
• 1-year change in greenhouse gas emissions (2024-2025): +0.1% (+9.7 million metric tons)
• 10-year change in greenhouse gas emissions (2015-2025): +22.3% (+2.9 billion metric tons)
• Population in 2025: 1,406,585,000 (17.1% of global total)