Sun dimming, also known extravagantly as “solar radiation management projects,” are the attempt to reduce the amount of sunlight making its way to the Earth’s surface by placing something in its path. Many believe that geoengineering projects such as these would go a long way to counteracting the effects of climate change.
Solar dimming does take place naturally, if and when a volcanic eruption spews enough ash into the atmosphere to minimize the levels of sunlight reaching the surface, however, manually implementing something like this is fraught with perils and unknowns.
A new study by Dr Peter Braesicke, from the Centre for Atmospheric Science at Cambridge University, looks at the possible impacts of sun dimming and the effect that it would have on the planet’s wider climate systems.
Teleconnections are the phenomenon of distant climate patterns relating to one another at large distance, such as the link between sea-level pressure at Tahiti and Darwin, Australia, which defines the Southern Oscillation.
“It is important that we look for unintended consequences of any sun dimming schemes,” said Braesicke. “We have to test our models continuously against observations to make sure that they are ‘fit-for-purpose’, and it’s important that we should not only look at highly averaged ‘global’ quantities.”
The research done by Braesicke and his team allow them to assess what would happen if a geoengineering project such as solar dimming was initiated.
“We have shown that important teleconnections are likely to change in such a geoengineered future, due to chemistry-climate interactions and in particular, due to changing stratospheric ozone,” concluded Braesicke. “In our model, the forced variability of northern high latitude temperatures changes spatially, from a polecentred pattern to a pattern over the Pacific region when the solar irradiance is reduced. Future geoengineering studies need to consider the full evolution of the stratosphere, including its chemical behaviour.”
In other words, while we might end up cooling our planet by minimizing how much solar radiation makes it into the atmosphere, we may conversely minimize the amount of rain that falls over Africa and Asia during the summer monsoons, thus affecting billions of peoples water supplies.
Everything is linked to everything else. Or, at least, that seems to be what the evidence is showing us.