New Harvard research shows how geoengineering can keep the worst effects of climate change at bay. Scientists already know that solar geoengineering can help minimize climate risks. This involves putting aerosols into the atmosphere, which then reflect sunlight and reduce global warming.
There are two main types of geoengineering: carbon dioxide removal and solar radiation modification. Carbon dioxide removal, also known as carbon capture, uses giant machines that suck greenhouse gases out of the atmosphere. While the technology was first discovered in the 1970s, it is much more effective today.
Both politicians and climate scientists applaud carbon sequestration, but it is expensive, Unfortunately. However, scientists have begun to work on inexpensive ways to use the technology.
While carbon capture is fairly straightforward, modifying solar radiation is a bit more complicated. Also known as solar geoengineering, this method reflects sunlight away from the Earth’s surface. In this way, the surface albedo or the amount of sunlight reflected off the Earth’s surface increases. By increasing the reflectivity of the planet’s surface, scientists can use solar geoengineering to deflect sunlight and cool the planet.
Shiny surfaces like snow and ice reflect most of the sun’s rays. However, scientists have to rely on geoengineering to reduce global temperatures with the melting ice caps quickly.
- Sea cloud shine
- Cirrus thinning
- Space-based techniques
- Stratospheric aerosol intervention
While these methods cannot eliminate climate change, they can significantly slow it down. Not to mention, scientists around the world have started exploring other options as well. When it comes to geoengineering, much of the research has focused on reducing physical changes to the climate. However, not many studies have investigated how solar geoengineering could affect the ecosystem, especially agriculture.
How geoengineering can slow down climate change
So researchers at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) decided to find out. They found that, surprisingly, solar geoengineering could help alleviate some of the worst effects of global warming on crops.
The Harvard researchers also collaborated with the following organizations:
- The Norwegian Research Center and the Bjerknes Center for Climate Research;
- Norwegian University of Science and Technology;
- National Center for Atmospheric Research in Boulder;
- Seoul National University; Y
- Chinese Academy of Sciences.
The research was published on May 20, 2021 in Nature food.
“Solar geoengineering research must address whether or not it is effective in reducing the human impacts of climate change,” said David Keith, professor of applied physics at SEAS and professor of public policy at Harvard Kennedy School. “Our article helps fill that gap by using the best crop model yet integrated into a climate model to examine the potential impact of solar geoengineering on agricultural yields.”
For the study, the researchers looked at three types of solar engineering. They focused on the injection of stratospheric aerosols, the glow of the sea sky and the thinning of cirrus clouds and how they affected crops. Specifically, they studied how the global yields of corn, sugar cane, wheat, rice, soybeans and cotton affected.
The team assumed an unchanged future, where emissions remained as they are today. In this scenario, the best way to protect crops from climatic disasters would be to lower the surface temperature. The researchers found that the three solar geoengineering methods listed above would cool the atmosphere enough to benefit crop yields.
Previous research suggested that lowering temperatures by injecting stratospheric aerosol can also reduce rainfall rates. This would lead to a lower yield of rainfed crops. However, these studies did not consider a crucial ecological factor in crop productivity and transpiration: humidity.
Humidity plays an important role in the success of the harvest.
“Relative humidity or vapor pressure deficit has a stronger control over plant water use and crop productivity than precipitation,” said Yuanchao Fan, member of the Harvard Solar Geoengineering Research Program and first author of the article. “We found that in a colder world under multiple scenarios, except for the thinning of cirrus clouds, there will be higher relative humidity, which will alleviate the water stress of rainfed crops. Our model shows that the change in precipitation resulting from the three solar geoengineering methods would, in fact, have a minimal effect on crops. “
Next, the team compared how solar geoengineering and reducing emissions affect agricultural productivity. They found that emission reductions increase cooling and humidity. However, this would not benefit crop yields as much as geoengineering. Reducing CO2 fertilization reduces the productivity of most crops, compared to geoengineering which also reduces temperatures.
The study says:
“General, increase overall returns ~ 10% in the three SGs and a 5% decrease in emission reductions. “
This discovery shows that other tools must be used in conjunction with reducing emissions. Increasing nitrogen fertilization and making land use changes would also help mitigate climate risks.
“Climate risks cannot be solved with a single tool; Even if emissions were phased out tomorrow, the world’s most vulnerable would continue to suffer from climate change, ”Keith said. “Policymakers need to consider how emissions cuts could be complemented with specific local adaptations to help farmers reduce climate impacts on agriculture and through global actions such as carbon removal and solar geoengineering.”
Co-authors of the research include Jerry Tjiputra, Helene Muri, Danica Lombardozzi, Chang-Eui Park, and Shengjun Wu. Harvard University’s Solar Geoengineering Research Program helped support the research in part.
Climate change and global warming have become major topics of discussion in recent years. If you look around, it is clear that our climate is undergoing rapid change. Hurricanes have gotten stronger, wildfires are out of control and deadly heat waves are increasing. In a warming world, crops also have a harder time growing. However, geoengineering could save the day.
New research shows that solar geoengineering, specifically, could increase crop yields by about 10%. By cooling the atmosphere with aerosols, you decrease heat stress on plants. This means that we have hopefully dodged a big bullet when it comes to climate change. As the world’s population continues to grow, we must find effective ways to feed everyone, even in a warming world.