Could we find inventive solutions to combat climate change?

When you ask scientists, you might hear a variety of responses, such as: “Probably not.” “Maybe?” or even “Are you crazy?”

Despite the skepticism, concepts for geoengineering—methods to either reduce carbon dioxide in the atmosphere or temporarily lower Earth’s temperature—are being discussed as potential short-term fixes for climate change, though they often sound more like plots from movies than feasible solutions.

Ideas include dehydrating the stratosphere, using bubble curtains to shield warm water and prevent glacial melting, injecting dust or gas into the atmosphere to deflect sunlight, enriching the oceans with iron to increase carbon dioxide absorption, or constructing massive facilities solely designed to capture carbon dioxide and bury it deep underground.

While these suggestions appear extreme, and even if they were effective, critics caution about potentially severe negative consequences. Nonetheless, amid a climate emergency, interest in these ambitious proposals is growing among experts and investors.

However, there’s an important caveat: none of these strategies would allow continued fossil fuel usage without repercussions. They are meant to serve as temporary measures while efforts to reduce fossil fuel dependence are underway.

Here’s a look at some concepts for how humans might assist in cooling our planet:

Carbon capture: Initiatives to remove carbon dioxide from the atmosphere

Carbon dioxide (CO2) is a major driver of climate change, acting like a blanket in the atmosphere that traps heat. The more CO2 present, the warmer the planet becomes. Numerous teams worldwide are focusing on methods to extract CO2 from the air and sequester it deep underground.

The technology already exists, with at least one version gaining acceptance. Organizations like the United Nations’ Intergovernmental Panel on Climate Change recognize it as crucial for addressing climate change.

On the more controversial side are efforts that capture CO2 emissions from oil and natural gas extraction as well as industrial processes, only to reinject it underground to facilitate more fossil fuel extraction—a cycle that critics argue does little to combat fossil fuel dependence. They contend that subsidies for this method essentially encourage pollution.

In contrast, less contentious methods entail creating massive fan-like machinery designed to draw in air, filter out carbon dioxide through chemical means, and store it underground.

Recently, a facility called Global Thermostat opened near Denver, capable of capturing about 1,000 tons of CO2 annually. This pilot project demonstrates the technology’s potential on a larger scale; however, experts assert that many more and larger facilities would be necessary to create a substantial impact. With humanity producing some 35 billion tons of CO2 each year, researchers from the Massachusetts Institute of Technology estimate that around 500 billion tons would need removal to revert to preindustrial atmospheric levels.

Pilot projects are also active in Switzerland, Norway, Canada, and Iceland.

Solar geoengineering: Utilizing sulfur to generate reflective clouds

Solar geoengineering proposes injecting sulfur dioxide or other substances into the stratosphere to reflect a portion of the sun’s energy back into space, helping to cool the Earth artificially.

This method mirrors the natural effects of some volcanic eruptions, which release vast quantities of dust and sulfur dioxide high into the atmosphere, where the materials remain due to weather patterns.

The 1991 eruption of Mount Pinatubo in the Philippines is a notable example, as it expelled over 15 million tons of sulfur dioxide 21 miles into the atmosphere, resulting in a substantial cooling of global temperatures of nearly 1 degree Fahrenheit during 1992 and 1993.

However, no one has yet devised a method to disperse the aerosols in the atmosphere on a scale that would be effective.

Although this proposal wouldn’t directly decrease the greenhouse gases present in the atmosphere, it might provide crucial time, according to Wake Smith, a lecturer at the Yale School of the Environment and author of “Pandora’s Toolbox: The Hopes and Hazards of Climate Intervention.”

“It’s an immature and controversial technology, and thus we should be cautious in our expectations. Yet, should global temperatures rise excessively, it appears we might have at least one tool that could assist.”

Currently, two startups are engaged in this field, though both are in early stages.

In 2022, a company named Make Sunsets conducted initial tests using biodegradable balloons filled with helium and sulfur dioxide that burst in the stratosphere. A U.S.-Israeli startup, Stardust Solutions, founded in 2023, has secured approximately $15 million in funding to develop the necessary technology.

Marine cloud brightening: Enhancing cloud reflectivity over oceans

Clouds naturally appear white and help reflect sunlight, thereby reducing the amount of heat that enters the atmosphere.

“If we are able to make clouds more persistent, especially above the oceans, we could potentially reduce overall temperatures significantly,”

“No one truly desires extra clouds over land, and perhaps we could enhance their whiteness instead of having them gray, which would help reflect more solar energy,” stated Hugh Hunt, an engineering professor at the Centre for Climate Repair at the University of Cambridge in the UK.

This concept is currently being trialed in Australia to cool the waters surrounding the Great Barrier Reef.

“The appealing aspect of this approach is that it can be carried out from boats, which seems less intimidating than sending planes 20 kilometers high to spray sulfuric acid. It’s simply saltwater being sprayed from vessels,” explained Shaun Fitzgerald, research director at Cambridge’s Center for Climate Repair.

However, a significant limitation of this method is that it can only be applied to small areas, like specifically cooling a reef, and is not feasible for larger global applications.

The positive aspect is that it has short-lived effects. “If you cease spraying the saltwater, the impacts on the clouds will dissipate within a day,” he noted.

In April, University of Washington scientists initiated a trial of this technology in San Francisco Bay, but it was swiftly halted by local authorities due to concerns over potential health and environmental hazards.

A bubble curtain for glaciers: Insulating ice to slow melting

The glaciers around the globe are melting, posing a threat due to their capacity to dramatically increase sea levels.

A study published in May revealed that the Thwaites Glacier in the extensive West Antarctica Ice Sheet may be eroding at a faster rate than previously thought. This glacier has been referred to as the Doomsday Glacier because it has enough water to potentially raise sea levels by up to 50 feet. (Recent studies suggest that this alarming scenario is not likely at this moment.)

Glaciers are melting primarily due to warmer, dense saline water from the ocean being driven underneath them, a phenomenon known as seawater intrusion.

One proposed solution is to prevent the warmer ocean water from reaching the base of the glaciers by implementing a curtain of air bubbles that would insulate the ice, causing the warmer water to flow around it and back to the sea instead of underneath the glacier.

“We are currently testing methods to pump air through a pipe with holes to produce a bubble curtain that disrupts the water flow,” Fitzgerald remarked.

Ocean fertilization: Capturing CO2 using dead algae

The goal here is to enrich the oceans with iron to boost the growth of algae and plankton blooms, which would absorb CO2 from the water into their biomass.

Approximately 30% of the world’s oceans suffer from low iron levels, leading to stunted growth of microscopic ocean plants and creatures such as algae and plankton.

Once these blooms die, they would sink to the ocean floor, effectively sequestering the CO2 there.

However, it remains uncertain whether the CO2 would remain locked away and how effective this technology would be overall. A 2023 study indicated that ocean iron fertilization could deplete nutrients in surrounding waters, possibly leading to a reduction in fish and other marine life by up to 5%.

Contributing: Ramon Padilla