Controversial methods of cooling the Earth by reflecting sunlight are gaining traction as global temperatures rise

ABC News looks at solutions to climate change and environmental issues with the series “Our Power: People, Climate and Our Future.”

According to a report by the World Meteorological Organization, the planet has witnessed an unrelenting range of record-breaking global temperatures as the speed and impact of climate change increases.

As the effects of human-enhanced climate change intensify, relatively untouched ideas are gaining momentum as potential short-term solutions to reducing Earth’s temperature.

Solar radiation modification or solar geoengineering is a concept that covers several different technologies or approaches to reflect sunlight into space to manipulate the planet’s temperature.

In 2023, the White House released a report outlining a plan to conduct more research on the two solar radiation modification approaches, saying it was important to better understand the risks and benefits of both technologies.

But solar geoengineering is a controversial topic among scientists, politicians and communities concerned about its potential impacts.

While some experts have been researching techniques that could cool the planet for decades, very few experiments have been conducted, and critics argue that we don’t know enough about the potential effects on climate and water events. And we don’t have air, water cycles or food production.

We need more scientists from more places who can ask questions about systems that are site-specific. We need policy makers who understand the cultural, social and political dynamics of their societies. The dynamism of activity, accountability, and in the first place about how to create policy and ideas, and we need it everywhere. Geoengineering Research, told ABC News.

Talaati says the vast majority of conversations about solar geoengineering come from countries like the United States, so his organization is reaching out to communities in the global south affected by climate change to raise awareness about Share solar geoengineering as a growing research area. .

Increased attention to solar geoengineering research has drawn scrutiny from critics who worry that research alone increases the likelihood that a country will choose these technologies. In 2022, more than 60 climate scientists and experts from around the world signed a letter calling for an agreement not to pursue solar geoengineering.

In the United States, Tennessee and several other states have passed laws that make it illegal to release chemicals or other substances with the intention of altering the climate or the intensity of sunlight.

Ginger Zee, ABC News meteorologist and senior climate correspondent, leads two research teams that could one day reflect enough sunlight to help cool Earth’s temperatures — brightening marine clouds and injecting stratospheric aerosols.

Clearing sea clouds

While solar radiation modification as a possible climate solution is still in the early stages of research, humans have been inadvertently altering the Earth’s radiation balance for more than a century.

Greenhouse gas emissions from ships crossing the globe have started a similar process, says Sarah Doherty, program director of the Marine Cloud Clearing Project and associate professor at the University of Washington.

“You can see where the ships are going from the ocean,” Doherty told ABC News. “The sulfur that they produce from their engines creates tiny particles in the atmosphere, often leaving bright cloud streaks and We call them ship routes.”

He says the Sea Cloud Clearing Project he oversees is studying ways to replicate the process by creating a clear shipping lane of sea salt.

Scientists at the University of Washington and a group called Silver Lining recently launched a first-of-its-kind outdoor study to better understand how sea cloud lighting technology works.

The study involves blowing tiny salt water particles into the air and using a variety of research tools to study the evolution of a sea salt aerosol plume as it rises in the atmosphere.

Scientists say that when sea salt aerosols reach stratocumulus clouds in the target area, they hope to find full-sized sodium molecules that will strengthen the existing clouds.

These molecules help absorb more water vapor in the sky to form new water droplets in the cloud. This effectively makes the cloud brighter meaning it can reflect more sunlight. By reducing the amount of sunlight that reaches the surface of the earth, the temperature of that place is effectively reduced.

Kelly Wanser, executive director of the nonprofit Silver Lining, which advocates for more research into the behavior of aerosols in the atmosphere, says the technology is still a long way from being a full-scale operational technology and would likely cost billions of dollars. For research and development.

“If we understand the science of what particles do with clouds and how they affect the climate system, it’s a win-win, whatever that science looks like, because we need to know it to know about Pollution and what’s going on nearby, Wanser told ABC News, is what you need to know to know if sea cloud brightening might be something to consider for climate mitigation.

Stratospheric aerosol injection

While marine cloud brightening would have more localized effects, another approach to cooling temperatures could have more widespread effects.

David Keith, a professor in the Department of Geophysical Sciences at the University of Chicago, has been at the forefront of research for an idea called stratospheric aerosol injection. While research on the topic has been relatively rare, in the past few years, more scientists are studying the topic, and some governments are starting to take a closer look.

Keith says that sulfur in the stratosphere can be very effective at neutralizing the warming effects of carbon dioxide by reflecting more sunlight. But he emphasized that solar geoengineering alone is not a cure for climate change.

“Any problem as complex as climate change rarely has only one solution. So reducing greenhouse gas emissions is certainly a necessary piece. But reducing greenhouse gas emissions will not solve climate change, because climate change is caused by The amount of CO2 in the air and reducing emissions just stops the amount we’re adding every year, Keith told ABC News.

Therefore, solar geoengineering can reduce the overall damage of climate change in combination with the reduction of greenhouse gas emissions and finally with the removal of carbon. This is its promise.

While more research is needed, one company says the effects of climate change are so dire that more drastic approaches are now warranted.

Make Sunsets is a company run by founders Luke Iseman and Andrew Song that sells what they call “cooling credits” that people can pay to send sulfur dioxide into the atmosphere.

By releasing a balloon filled with sulfur dioxide and helium, the company says it will send the sulfur dioxide into the atmosphere to reach the stratosphere at an altitude of more than 60,000 feet. At this height, the balloon jumps and releases sulfur dioxide into the air.

The purpose of using sulfur dioxide is to mimic the cooling effects that volcanic eruptions can have on Earth’s global temperature. The U.S. Geological Survey says the release of sulfur dioxide into the atmosphere following a volcanic eruption can have one of the most significant climate effects because the particles reflect sunlight into space and lower Earth’s temperature.

Sunsets says the company put a total of less than 75 pounds of sulfur dioxide into the stratosphere last year. Eisman admits the amount is “small” but it’s just a start.

Academic researchers and governments argue that they should act carefully and proceed with caution, but the two company founders argue that we no longer have that luxury.

“I would summarize it by saying that we’ve done such a poor job of geoengineering our climate over the last few hundred years with our carbon emissions that we now need to geoengineer in a positive way to compensate,” Eisman said.

While the solar geoengineering debate continues to heat up, current efforts to modify solar radiation are still very small in scale compared to what would be needed to significantly affect the Earth’s radiation balance and actually lower global temperatures.

But there is a push to focus research on solar geoengineering as a possible way to address warming and understand its consequences before considering these full-scale, operational methods.

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