Solar geoengineering could cause unwanted changes in climate, new modelling suggests

Solar geoengineering could cause unwanted changes in climate, new modelling suggests

SOURCE: Physics World DATE: June 20, 2020 SNIP: Using aerosols to reflect sunlight and cool the planet will weaken storm tracks in the temperate latitudes in both hemispheres, an international team of scientists warn. Their modelling suggests that while such solar geoengineering schemes could reduce the severity of winter storms, they would also stagnate weather systems in the summer. This could lead to more intense heat waves, increases in air pollution, and changes in ocean circulation. Solar geoengineering involves cooling the Earth by reflecting incoming sunlight and is seen by some scientists as a way of mitigating the effects of global warming. One popular strategy involves placing reflective aerosols in the stratosphere – using aircraft, balloons or blimps – to block sunlight. But the effects of solar geoengineering are unknown. It would not work as simply as cooling the planet and therefore returning Earth’s climate to pre-industrial levels. Climate under solar geoengineering would be different, as there would still be marked increases in atmospheric carbon dioxide levels. Charles Gertler, a graduate student in the Department of Earth, Atmospheric and Planetary Sciences at the Massachusetts Institute of Technology, in the US, and colleagues were interested in how injecting aerosols into the atmosphere would impact the pole‐to‐equator temperature gradient in both hemispheres, and the effect that could have on extratropical storm tracks. These are regions in the mid and high latitudes with heightened incidences of storms known as extratropical cyclones, which play a significant role in determining the day-to-day weather conditions in many parts of the world. “Our results show that solar geoengineering will not simply reverse climate change,” Gertler explains....
Wallace Smith Broecker, the ‘grandfather’ of climate science, leaves a final warning for Earth

Wallace Smith Broecker, the ‘grandfather’ of climate science, leaves a final warning for Earth

SOURCE: NBC DATE: March 3, 2019 SNIP: After struggling with heart disease for decades, the renowned climate scientist Wallace Smith Broecker had made it clear he was acutely aware of his own mortality. So when he sat down in front of a video camera to record a final message to his fellow scientists in mid-February, the 87-year-old researcher knew his days were few. The man who popularized the term “global warming” and first described the critical role oceans play on climate had an urgent message for 40 of the world’s top climate scientists. Humanity is not moving quickly enough to slow the production of carbon dioxide that is warming the Earth, Broecker said Feb. 11, his livestreaming image projected onto a big screen at Arizona State University, where researchers had met to discuss untested solutions to global warming. It was time for humankind and the world’s scientific community to begin to seriously study more extreme solutions to the climate crisis, Broecker said. That included creating a massive solar shield in the Earth’s atmosphere, a tactic known variously as “geoengineering,” “the sulfur solution,” “solar radiation management” and the “Pinatubo Strategy.” A week after his dramatic appeal, Broecker died of congestive heart failure, inspiring praise for his work as the “grandfather” of modern climate science. His death, and his final message to scientists, re-energized the debate over the sort of re-engineering of the Earth’s climate systems that Broecker and other academics had broached as early as the 1970s. Many scientists have been hesitant about pursuing such an extreme measure, citing scientific, ethical, legal and political dilemmas. Tampering with Earth’s atmosphere was...
Volcanoes show why solar geoengineering can’t save our food from climate change

Volcanoes show why solar geoengineering can’t save our food from climate change

SOURCE: Vox DATE: August 8, 2018 SNIP: As we pump more carbon dioxide into the atmosphere and the Earth traps more heat, scientists predict that the severity and frequency of heat waves will continue to increase. Which might lead one to wonder: Is there a way to turn down the planet’s thermostat? One concept gaining momentum is geoengineering: deliberately manipulating the Earth’s climate. Though currently only being tested in very small experiments, it includes solar radiation management — brightening clouds, making the ground more reflecting — and carbon dioxide removal, whether through direct air capture or planting more trees. Fortunately, volcanoes are a handy, excellent model for one form of geoengineering. In big eruptions, they can spew huge quantities of sulfate aerosols into the stratosphere — exactly what some advocates have proposed as a way to block some sunlight and manually cool the planet. In a study published Wednesday in the journal Nature, researchers used two past volcanic eruptions to estimate how geoengineering would affect the yield of major food crops. It’s one of the first studies ever to look at the potential consequences of geoengineering using real-world data. And the consequences look pretty serious. “If we think of geoengineering as an experimental surgery, our findings suggest that the side effects of the treatment are just as bad as the original disease,” co-author Jonathan Proctor, a researcher at the University of California Berkeley, told reporters. In other words: When it comes to crops, solar geoengineering could trade one problem (heat-related declines) for another (crop losses due to less light). Specifically, the research team examined what happened to maize, soy,...
Climate Engineering, Once Started, Would Have Severe Impacts If Stopped

Climate Engineering, Once Started, Would Have Severe Impacts If Stopped

SOURCE: Rutgers University DATE: January 21, 2018 SNIP: Facing a climate crisis, we may someday spray sulfur dioxide into the upper atmosphere to form a cloud that cools the Earth, but suddenly stopping the spraying would have a severe global impact on animals and plants, according to the first study on the potential biological impacts of geoengineering, or climate intervention. The study was published online today in Nature Ecology & Evolution. The paper was co-authored by Rutgers Distinguished Professor Alan Robock, research associate Lili Xia and postdoc Brian Zambri, all from the Department of Environmental Sciences at Rutgers University–New Brunswick. “Rapid warming after stopping geoengineering would be a huge threat to the natural environment and biodiversity,” Robock said. “If geoengineering ever stopped abruptly, it would be devastating, so you would have to be sure that it could be stopped gradually, and it is easy to think of scenarios that would prevent that. Imagine large droughts or floods around the world that could be blamed on geoengineering, and demands that it stop. Can we ever risk that?” The geoengineering idea that’s attracted the most attention is to create a sulfuric acid cloud in the upper atmosphere as large volcanic eruptions do, Robock said. The cloud, formed after airplanes spray sulfur dioxide, would reflect solar radiation and cool the planet. But airplanes would have to continuously fly into the upper atmosphere to maintain the cloud because it would last only about a year if spraying stopped, Robock said. He added that the airplane spraying technology may be developed within a decade or...
Why you need to get involved in the geoengineering debate – now

Why you need to get involved in the geoengineering debate – now

SOURCE: The Conversation DATE: October 19, 2017 SNIP: The prospect of engineering the world’s climate system to tackle global warming is becoming more and more likely. The 2015 Paris Agreement set out near universal, legally binding commitments to keep the increase in global temperature to well below 2°C above pre-industrial levels and even to aim for limiting the rise to 1.5°C. The Intergovernmental Panel on Climate Change (IPCC) has concluded that meeting these targets is possible – but nearly all of their scenarios rely on the extensive deployment of some form of geoengineering by the end of the...