How US is trying ‘sun blocking’ to cool the Earth – Times of India

NEW DELHI: In a groundbreaking experiment on a decommissioned aircraft carrier in San Francisco Bay, engineer Matthew Gallelli conducted the United States’ first outdoor test of a technology aimed at combating global warming. The purpose of this test was to evaluate a method designed to brighten clouds and reflect some of the sun’s rays back into space, offering a temporary solution to the planet’s escalating temperatures.Scientists aimed to verify whether the device could consistently disperse the correct size salt aerosols in the open environment, a critical step before proceeding to potentially alter the cloud composition above Earth’s oceans, a New York Times report said.
In this innovative approach to counteracting global warming, US scientists are examining the potential of ‘sun blocking,’ a method that involves reflecting sunlight back into space to cool the Earth. This strategy, known as solar radiation modification (SRM), has gained traction following a White House report indicating the US’s openness to research its feasibility and effectiveness in combating climate change.
The concept of ‘sun blocking’ or solar radiation modification could theoretically reduce global temperatures by reflecting sunlight away from the Earth. One proposed method involves stratospheric aerosol injection, where airplanes would disperse sun-blocking particles such as sulfur dioxide into the upper atmosphere. This technique aims to create a reflective mist that would shield the Earth from the sun’s rays. The potential of this method was inadvertently demonstrated when the eruption of Mount Pinatubo in 1991 led to a temporary global temperature decrease of 0.5°C. Researchers from Yale University have even suggested that this approach could help refreeze the Earth’s poles.
Meanwhile, the UN Environmental Program (UNEP) has concluded that, given current scientific understanding, large-scale deployment of SRM technologies is not advisable. UNEP’s Chief Scientist, Andrea Hinwood, emphasized that SRM cannot replace the need to reduce greenhouse gas emissions but didn’t dismiss the possibility of revisiting this assessment should climate action remain insufficient.
David Santillo, a leading scientist with Greenpeace International, has expressed significant doubts about the feasibility of altering solar radiation to combat climate change. He pointed out that employing techniques like marine cloud brightening on a global scale to reduce temperatures could lead to unpredictable and potentially unquantifiable outcomes.
“You could well be changing climatic patterns, not just over the sea, but over land as well,” Santillo told the New York Times. He emphasized the dangers of such interventions, stating, “This is a scary vision of the future that we should try and avoid at all costs.”