As climate change continues to warm the planet, marine heatwaves are becoming more frequent, intense, and destructive. Scientists warn that if current emissions trends continue, 97% of the world’s oceans could experience hotter and longer-lasting marine heatwaves by 2069, threatening marine ecosystems, fisheries, and the livelihoods of billions of people. Against this backdrop, a new study suggests that solar geoengineering may protect up to 75% of oceans from heatwaves, depending on how aggressively the technology is deployed.

Published in Environmental Research: Climate, the research highlights both the promise and the limitations of solar geoengineering as a potential tool to reduce ocean warming.

Why Marine Heat Waves Matter

Most people are familiar with heatwaves on land, but oceans can experience similar extreme temperature events. These prolonged periods of unusually warm ocean water can disrupt marine ecosystems and have severe environmental and economic consequences.

The impacts are already being felt around the world:

• More than half of the living coral in Australia’s Great Barrier Reef has been lost over the past 30 years, with marine heatwaves identified as a major contributor.
• A massive marine heatwave along the U.S. West Coast between 2014 and 2016 caused sea lions and seabirds to starve as prey species moved to cooler waters.
• In 2016, unusually warm waters off southern Chile triggered a toxic algal bloom that killed 100,000 metric tons of salmon and trout, marking the largest fish farm mortality event ever recorded.
• Studies show that a single marine heatwave can cause economic losses worth billions of dollars.

For researcher Lala Kounta, the issue became personal after unusually warm waters off Senegal’s coast in 2020 caused a toxic algal bloom that sickened hundreds of fishermen.

Also Read: Watchdog Warns Indian Ocean Warming Is Putting Marine Life At Risk

What Is Solar Geoengineering?

One proposed climate intervention is stratospheric aerosol injection, a form of solar geoengineering designed to reduce the amount of sunlight reaching Earth. The concept involves releasing particles such as sulfur dioxide into the stratosphere, where they reflect a portion of incoming sunlight back into space.

The idea is inspired by volcanic eruptions. When Mount Pinatubo erupted in 1991, millions of tons of sulfur dioxide entered the atmosphere, temporarily lowering global temperatures by about 0.6°C for nearly two years.

Potential Ocean Protection Under Different Scenarios

Also Read: May 2026 Was Second Warmest May On Record Globally, Says Copernicus Climate Report

What the New Study Found

Researchers used computer simulations to compare future ocean conditions with and without solar geoengineering. Their models showed that if greenhouse gas emissions continue unchecked, average ocean temperatures could rise by approximately 1°C by 2069, causing marine heatwaves to become more severe across almost all ocean regions.

The study found that solar geoengineering may protect up to 75% of oceans from heatwaves under an aggressive deployment scenario designed to keep global warming below 1°C.

Regions showing the greatest benefits included:

• Tropical Atlantic Ocean
• Indian Ocean
• Arctic Ocean
• South Atlantic Ocean
• West African Coast

However, the protection would not be evenly distributed.

Also Read: Worst-Case Global Warming Forecast Revised Down To 3.5°C By 2100

The Challenge of Unequal Benefits

Even under the most aggressive scenario, nearly 25% of the world’s oceans would still experience worsening marine heatwaves. Areas expected to remain vulnerable include:

• North Atlantic Ocean
• Northern Pacific Ocean
• Tropical Pacific Ocean
• Parts of the Southern Ocean

Researchers warn that some regions could transition from occasional heatwaves to almost constant overheating by the end of the century.

This uneven distribution raises important political and ethical questions about who would benefit and who would bear the risks if solar geoengineering were ever implemented.

Also Read: Wet-Bulb Temperature Risk In India: Why Rising Heat Is Becoming A Serious Survival Threat

Not a Replacement for Emissions Reductions

While the findings suggest that solar geoengineering may protect up to 75% of oceans from heatwaves, scientists stress that it is not a substitute for cutting greenhouse gas emissions.

The technology would not reduce atmospheric carbon dioxide levels, meaning other climate-related problems would continue. Rising CO₂ concentrations would still contribute to ocean acidification, threatening shell-forming organisms such as mussels, clams, sea snails, and sea urchins that form the foundation of marine food webs.

Researchers also caution that abruptly ending a large-scale geoengineering program could trigger rapid temperature increases as accumulated greenhouse warming is suddenly revealed.

Also Read: Warming Oceans Are Shrinking Fish Size, Threatening Global Seafood Supply

A Tool Worth Studying, Not a Climate Solution

The study concludes that solar geoengineering may protect up to 75% of oceans from heatwaves, but significant uncertainties remain. Scientists still know relatively little about the ecological impacts, effects on rainfall patterns, crop production, and long-term environmental consequences.

For now, researchers view solar geoengineering as an area requiring further investigation rather than a ready-made climate solution. While it may offer temporary relief from rising ocean temperatures, experts agree that reducing greenhouse gas emissions remains the most effective and reliable strategy for protecting marine ecosystems and limiting future climate change.

Also Read: Warming Climate Drives Decline Of Brazil’s Abrolhos Coral Reefs

Frequently Asked Questions

1. What is solar geoengineering?

Solar geoengineering is a proposed climate intervention technique that aims to reflect a small portion of the Sun’s energy back into space to reduce global warming. One of the most discussed methods is stratospheric aerosol injection, where reflective particles are released high into the atmosphere.

2. How could solar geoengineering help oceans?

By slightly reducing the amount of solar radiation reaching Earth, solar geoengineering could lower ocean temperatures and reduce the intensity and frequency of marine heat waves that damage marine ecosystems.

3. How much of the ocean could be protected?

According to the study, solar geoengineering may protect up to 75% of oceans from heatwaves under an aggressive deployment scenario. Under a more moderate approach, only 20–25% of oceans may see significant protection.

Also Read: New Study Outlines Best And Worst Outcomes Of Antarctic Warming