Recent years have witnessed unprecedented global temperature rises, with 2023. 2024 and 2025 recording some of the hottest conditions ever measured. While the primary driver of this warming remains the unabated rise in greenhouse gas emissions from fossil fuel combustion, emerging research suggests that regulatory measures—such as the global sulphur ban in shipping—may also be playing a role in the climate system.
A Record-Breaking Warming Trend
The global climate has been warming at an accelerated pace over the last few years. Extreme heat events, record-breaking temperature anomalies, and widespread heatwaves have become the new norm. Data from various monitoring agencies confirm that the past couple of years have broken so many previous temperature records, largely due to the continuous build-up of greenhouse pollution.
The Global Sulphur Ban: An Overview
In an effort to reduce harmful air pollutants and improve public health, the International Maritime Organization (IMO), a specialised agency of the United Nations, introduced a global sulphur ban. This regulation, which came into effect on 1 January 2020, restricts the use of high‑sulphur fuel oil (HSFO) in marine vessels to a maximum sulphur content of 0.50%, unless the ship is equipped with an approved scrubber system. Vessel operators now face three main options for compliance:
- Switch to IMO‑Compliant Low‑Sulphur Fuel: This fuel meets the stringent sulphur limits but has faced supply challenges, especially during disruptions like the COVID‑19 pandemic.
- Install and Use Scrubbers: Ships may continue using HSFO if they have installed approved scrubber systems, though these systems themselves have raised environmental concerns in certain regions.
- Alternative Fuels: Options such as LNG or methanol offer a cleaner-burning alternative, albeit with their own economic and logistical considerations.
While the IMO set the global standard, Europe has been at the forefront of supporting and enforcing stricter environmental regulations. European countries and ports have often adopted additional measures to ensure compliance with sulphur limits and address concerns about the environmental impact of scrubbers. For example, several European nations have banned the use of open-loop scrubbers, which discharge untreated wash water back into the ocean, adding further restrictions on sulphur emissions in European waters. The EU has also actively participated in discussions to tighten regulations and has led efforts to promote cleaner technologies.
The CMS Law Now article on “The Global Sulphur Ban – One Year On” provides detailed insights into the implementation challenges, enforcement mechanisms, and compliance strategies associated with the ban. It highlights that while the primary goal of the regulation is to reduce sulphur oxide emissions and improve air quality, the global disruption of fuel supply chains and technical compliance issues have added layers of complexity to its enforcement.
The Cooling Role of Sulphate Aerosols
An often overlooked aspect of sulphur emissions is their role in the atmospheric aerosol system. When sulphur oxides (SOₓ) are released into the atmosphere, they react with water vapour to form sulphate aerosols. These tiny particles are highly reflective—they scatter incoming solar radiation back into space, creating a natural cooling effect often described as a “sunshade” for the Earth.
According to a detailed analysis by Carbon Brief, the implementation of low‑sulphur shipping rules has led to a substantial reduction in sulphur oxide emissions. While this change brings significant public health and environmental benefits (such as reduced acid rain and improved air quality), it also means that fewer sulphate aerosols are formed in the atmosphere. Consequently, this loss of aerosol cooling can contribute to a modest, yet measurable, warming effect on the global climate.
Balancing Air Quality and Climate Objectives
The situation presents a classic example of environmental policy trade-offs. On one hand, the sulphur ban is a critical step in curbing pollutants that have immediate adverse effects on human health and marine ecosystems. On the other hand, by reducing the formation of cooling sulphate aerosols, the ban inadvertently removes a partial counterbalance to the warming effects of greenhouse gases.
Looking Ahead
As the planet continues to warm by 1 degree at a time, understanding and managing these complex interactions becomes ever more critical. People often think a few degrees aren’t a problem, but this isn’t where we are heading—we’re already there, and we’re continuing to add a few more degrees at a time.
Today, we’ve already changed the Earth’s environmental conditions, making it difficult for certain segments of animal and plant life to survive. But we are not just trending towards a difficult environment; we’re heading towards an impossible one, where most species will struggle to live. Going from 40°C to 50°C, then 50°C to 60°C, will soon leave very little room for anything to survive.
Earth’s climate used to change very subtly over thousands of years; now, we are rapidly changing it in just tens of years. Unless we treat climate change seriously and reduce emissions, we will have to start coming up with new, novel technological drastic means of attempting to lower Earth’s temperature. One recent but serious suggestion is to blow up a very large nuclear bomb somewhere on Earth as to create a mini-nuclear winter.
