By: Jane Marsh

As the planet keeps warming, the need for new, far-reaching climate solutions grows increasingly evident. It is clear that current efforts are insufficient to stop climate change, but there is some debate about the next step. One of the most controversial suggestions is solar geoengineering.

Solar geoengineering dates back to the first report on climate change in 1965, predating suggestions to reduce emissions. The practice has regained steam as climate issues have grown more severe, but not all researchers think it should. Some say it could endanger the planet.What Is Solar Geoengineering?

Geoengineering is the practice of manipulating the environment to cool the planet. Unlike photovoltaic solar power which absorbs the photons within the sun’s rays, solar geoengineering is a branch that focuses on reflecting sunlight away from the Earth’s surface to reduce the greenhouse effect.

Large volcanic eruptions demonstrate the principle behind solar geoengineering. The 1991 eruption of Mount Pinatubo cooled the Earth by 1.3 F for three years by blocking sunlight with a massive sulphur dioxide cloud. Some researchers suggest they could achieve a larger version of this effect by injecting similar aerosols into the atmosphere.

What chemicals scientists should use and how much they will need is still uncertain. Some want to research these factors further, but many have warned that the practice is too dangerous to warrant consideration. Here is why.

A Long and Challenging Process

The first downside to solar geoengineering is that it may take years to produce meaningful results. Pinatubo’s sulphur dioxide cloud was the largest ever observed, reaching 20 miles into the atmosphere. Even then, it only took a few years for temperatures to rise to their pre-eruption levels.

Researchers would have to replenish this aerosol layer for years, even decades, to offset global warming’s current pace. That would be remarkably difficult to achieve, and any lull in the process could be dangerous. A 2018 Yale study found that temperatures would rise to six times faster than current climate change after a sudden stop in solar geoengineering.

Once the world starts pursuing this strategy, it would have to maintain it or risk severe consequences. That is a considerable amount of effort, considering geoengineering does not impact the root causes of climate change. It only buys the world more time to reduce emissions.

Possible Environmental Side Effects

Even if the world can sustain these operations, they could have severe side effects. Reflecting sunlight may lower temperatures, but such a large-scale interference with nature could also have unintended consequences. More than 60 scientists recently published an open letter calling to end solar geoengineering development because of these risks.

The 2018 Yale study also found that sudden temperature changes, even if in the right direction, could jeopardize vulnerable species. Those in the Amazon basin, eastern Pacific and Alaska could go extinct as temperatures in these areas shift more dramatically than in the rest of the world.

Other studies have found that blocking sunlight reduces photosynthesis, potentially endangering plant life. While cooler temperatures would reduce some stress of plants, previous volcanic eruptions show that the drop in photosynthesis counteracts these benefits. Crop yields would likely decrease and natural plant life in change-sensitive areas may also struggle.

One of the greatest challenges of solar geoengineering is that environmental shifts are rarely even. Blocking sunlight in the Northern Hemisphere could increase droughts in India and Africa and make tropical cyclones more severe.

Scientists warn that these uneven side effects are complex, and the world does not fully understand what widespread solar geoengineering could do. Large-scale experiments would be necessary to understand these impacts, but at that point, people would be practicing solar geoengineering, not testing it.

The State of Solar Geoengineering Today

Despite these risks, solar geoengineering has become increasingly popular recently. In 2020, the U.S. government allotted $9 million to research these technologies. Investors like Bill Gates have also poured funds into solar geoengineering research.

Some researchers worry that much of this enthusiasm comes from companies profiting from fossil fuels. Focusing on efforts to mitigate the impact of the greenhouse effect may distract from the systems that produce these emissions in the first place.

Funding and conversations around solar geoengineering have risen lately, but large-scale experimentation has yet to occur. Warnings from researchers like the recent open letter have dissuaded many larger efforts. However, as the need for widespread climate solutions grows, the future of solar geoengineering remains uncertain.

Solar Geoengineering Could Be Dangerous

Solar geoengineering sounds promising on paper, but its potential side effects are severe, and there is much we still do not know about it. For now, research seems to suggest that it is more important to focus on the root causes of climate change. The Earth must cool but reflecting sunlight on a global scale could endanger people and nature in some areas.

Author bio:

Jane works as an environmental and energy writer. She is also the founder and editor-in-chief of Environment. co.