Fighting global warming: scientists propose to artificially cool the Earth

Irina Ziganshina

Until recently, the idea of changing the very atmosphere of the Earth to cool it seemed too radical. Today large sums are allocated for its implementation. The New York Times writes about solar geoengineering.

An approach called solar climate intervention, or solar geoengineering, is to reflect most of the solar energy back into space. The effect that this has - a sharp drop in global temperatures - is reminiscent of what happens when a powerful volcanic eruption (as it was ten years ago in Iceland with Eyjafjallajokull) produces ash clouds covering the sun. Until recently, solar geoengineering seemed like a fantasy, but in the current situation: the time for thinking is over, there are not enough promising strategies, and hurricanes, forest fires and floods are becoming more destructive - researchers and politicians started talking about this option should not be discounted.

The American company SilverLining, engaged in projects in the field of climate preservation, has announced the allocation of $ 3 million in research grants: among others, Cornell University, Washington University, Rutgers University, and the National Center for Atmospheric Research will receive money. The project, dubbed the Safe Climate Research Initiative, will focus on practical issues such as how high to inject solar-reflecting aerosols into the atmosphere, how to spray optimal sized particles into clouds, and how this will affect global food supplies.

This is not the first solar geoengineering project. The US National Oceanic and Atmospheric Administration has already received $ 4 million from Congress for research in this area. Experiments are underway in Australia to determine if this technology can save the Great Barrier Reef. There is a possibility that other countries are also doing geoengineering without publicly announcing it.

One way to cool the Earth is to inject aerosols into the upper atmosphere, particles of which could reflect sunlight from our planet. Researchers at Cornell University who have received the grant say they are 100% confident in their ability to cool the planet. But first it is necessary to understand how this will affect other processes: the strength of hurricanes, the risk of forest fires, ice melting, agricultural productivity... To answer these questions, scientists will simulate weather effects caused by aerosol spraying into the atmosphere over different parts of the globe as well as at different heights.

Another grant-receiving institution, the National Center for Atmospheric Research in Boulder, Colorado, sees a top goal as finding a sweet spot - enough artificial cooling that will reduce extreme weather events without causing changes in regional rainfall patterns and the like...

Spraying aerosols into the stratosphere is not the only way to reflect sunlight. The Australian government is funding research into what is known as "sea cloud brightening", which aims to enhance the ability of clouds to reflect light by spraying salt water into the air. The salt particles are supposed to work like crystals, around which many small water droplets are formed, increasing the brightness of the clouds. Australian researchers hope this method can save the Great Barrier Reef. The rise in water temperature during the so-called sea heat waves accelerates reef degradation. By making the clouds reflect more light, it may be possible to cool the water enough to slow or stop this process. The problem may be that the technology will have to be applied on a large scale. Scientists estimate that covering the entire reef would require 500 to 1,000 barges or platforms to spray water.

In the photo: solar geoengineering should produce results similar to the one made in 2010 by the Eyjafjallajökull volcano, which covered the sun with ash clouds.