solar radiation management

When soaring temperatures, extreme weather and catastrophic wildfires hit the headlines, people start asking for quick fixes to climate change. The U.S. government just announced the first awards from a US$3.5 billion fund for projects that promise to pull carbon dioxide out of the air. Policymakers are also exploring more invasive types of geoengineering − the deliberate, large-scale manipulation of Earth’s natural systems. The underlying problem has been known for decades: Fossil-fuel vehicles and power plants, deforestation and unsustainable agricultural practices have been putting more carbon dioxide into the atmosphere than the Earth’s systems can naturally remove, and that’s heating up the planet. Geoengineering, theoretically, aims to restore that balance, either by removing excess carbon dioxide from the atmosphere or reflecting solar energy away from Earth. But changing Earth’s complex and interconnected climate system may have unintended...

Imagine a future where, despite efforts to reduce greenhouse gas emissions quickly, parts of the world have become unbearably hot. Some governments might decide to “geoengineer” the planet by spraying substances into the upper atmosphere to form fine reflective aerosols – a process known as stratospheric aerosol injection. Theoretically, those tiny particles would reflect a little more sunlight back to space, dampening the effects of global warming. Some people envision it having the effect of a volcanic eruption, like Mount Pinatubo in 1991, which cooled the planet by about half a degree Celsius on average for many months. However, like that eruption, the effects could vary widely across the surface of the globe. How quickly might you expect to notice your local temperatures falling? One year? Five years? Ten years? What if your local temperatures seem to be going up? As it turns out, that is exactly what could happen. While modeling studies show that strato...