Scientists propose safe experiments to reflect sunlight and cool earth as climate crisis accelerates

As global temperatures continue their alarming rise, researchers are calling for controlled experiments with solar radiation management—a controversial but potentially crucial climate intervention that could buy humanity time to address the root causes of global warming.

The stark reality driving this discussion is undeniable: 2024 marked the first complete year with temperatures exceeding 1.5°C above 19th-century averages, while fossil fuel consumption is projected to reach new peaks in 2025. Current carbon removal technologies are capturing only tens of thousands of tonnes of CO2 annually—a fraction of the 5-10 billion tonnes scientists say we need to remove each year. Despite being essential, emission cuts and carbon removal alone may no longer be sufficient to prevent catastrophic climate impacts.

The concept of reflecting sunlight to cool Earth isn’t new. In 1965, President Lyndon B. Johnson’s science advisers identified solar radiation management as potentially the only viable method to reduce planetary temperatures. The approach would work by slightly increasing Earth’s natural reflectivity—currently about 30% of incoming sunlight—to perhaps 31%, effectively strengthening our planet’s heat shield.

While emission reductions remain the primary solution, growing ecological damage and human suffering are prompting scientists to seriously consider whether carefully designed experiments with solar radiation management could provide a critical stopgap. The key emphasis is on “safely”—any research would need robust international oversight and extensive risk assessment to avoid unintended consequences while potentially preventing far worse climate catastrophes.