Shipping Pollution (Sulfur Emissions and Climate Change)

There are several critical issues associated with marine fuel pollution used in international shipping. Shipping pollution is a global problem, spreading air pollution across the world. Historically, marine fuels have contained higher levels of sulfur due to the lower cost of lower-grade fuel oil. However, heavy fuel oil contains, on average, 2700 times more sulfur than road fuel. Sulfur in fuel leads to emissions of sulfur dioxide (SO2) and contributes to the formation of secondary particulate matter (PM), which is highly detrimental to both human health and the environment.

Acid rain is a consequence of chemical reactions initiated when compounds like sulfur dioxide and nitrogen oxides are released into the atmosphere. These substances can rise into the upper atmosphere, where they mix and react with water, oxygen, and other chemicals, forming more acidic pollutants known as acid rain. Acid rain, when absorbed by the ground, can dissolve essential nutrients like magnesium and calcium, crucial for the health of trees. Additionally, it releases aluminum into the soil, hindering trees’ ability to absorb water. This influx of chemicals also alters the chemistry of seawater, reducing its pH and capacity to store carbon. Ocean acidification, often dubbed “osteoporosis of the sea,” can erode the minerals essential for the shells and skeletons of marine life, including oysters, clams, lobsters, shrimp, and coral reefs.

Exposure to particulate matter (PM10 and PM2.5) poses numerous health risks, compromising respiratory and cardiac health. PM2.5, in particular, can deeply penetrate the lungs, causing inflammation and damage to lung tissue. Currently, approximately 7 million people die each year from exposure to particulate matter, with millions more experiencing severe health complications. Health impacts of air pollution encompass a wide range of ailments, including Alzheimer’s disease, asthma, bronchitis, cancer, cataracts, chronic obstructive pulmonary disease (COPD), dementia, developmental damage, emphysema, gastrointestinal disorders, heart ailments, heart attacks, immune system dysfunction, ischaemic heart disease, impaired brain development in children, kidney disease, liver disease, lung disease, premature death, pneumonia, nasal and upper respiratory tract health problems, neurological disorders, reproductive harm, respiratory system failure, skin diseases, and strokes.

The Restriction of Sulfur in Marine Fuel
In 2020, the International Maritime Organization (IMO) introduced regulations imposing strict limits on the sulfur content of marine fuels. These rules mandated a reduction in the maximum percentage of sulfur from 3.5% to 0.5% for all ships operating worldwide.

The restriction on sulfur in marine fuel has indirectly contributed to increased ocean surface temperatures. As sulfur emissions from marine fuels decrease, ships transition to cleaner fuels with lower sulfur content. However, these cleaner fuels often contain higher levels of carbon dioxide (CO2), a potent greenhouse gas. The increased CO2 emissions from ships burning cleaner fuels exacerbate global warming, leading to elevated ocean surface temperatures. This phenomenon underscores the broader impact of human activities on climate change, driving overall increases in global temperatures, including those of the Earth’s oceans.

According to a NASA-led analysis, global average sea level rose by approximately 0.3 inches (0.76 centimeters) from 2022 to 2023. When our paper, “Climate Change: Rate of Acceleration,“ was authored in 2023, the swift acceleration of this trend was unforeseen. Initially projected to double over 100 years, the rate of sea level rise dramatically escalated, shortening the doubling period to just 10 years by 2020. Recent observations suggest a further compression of this doubling period to a mere 2 years, raising significant concerns. It is imperative to acknowledge and address this alarming trend, hoping it is not indicative of a new norm but rather an anomaly.

Sidd elaborated, stating, “I suspect this is linked to the large jump in sea surface temperature last year, perhaps due to the restriction on sulfur in marine fuel. The rapid warming and expansion of the ocean’s surface warrant close observation to determine if this trend is sustained.” 2023, the hottest year on record overall, was also the warmest year recorded for the world's oceans. A study published in Advances in Atmospheric Sciences found that the upper 2,000 meters of the ocean warmed by 15 zettajoules in 2023 compared to 2022. As water warms, it expands. This thermal expansion contributes to approximately half of the current rise in sea level.

Health and Wellness
Humans will experience greater loss and damage to life and quality of life from air pollution, decreasing supply of potable water, extreme weather events, disease, and other adverse health outcomes The greatest short term climate change risk to human health is deadly humid heat (wet-bulb temperature).

The environmental changes and uncertainties associated with climate change can contribute to mental health issues, including anxiety, depression, and post-traumatic stress disorder (PTSD). Almost all survivors of climate-related disasters suffer from mental distress and experience PTSD. Of those who have not experienced climate disasters, over two-thirds of U.S. adults (68%) report having climate change anxiety.

* Our climate model employs chaos theory to comprehensively consider human impacts and projects a potential global average temperature increase of 9 degrees Celsius above pre-industrial levels. Humans face severe challenges if global temperatures rise above 1.5 degrees Celsius. At this threshold, much of the Earth may become uninhabitable. If current trends persist, temperatures and humidity levels could reach a point where wet-bulb temperatures are unsustainable for human life. Regardless, continued climate change will result in exponential loss and damage.