China's geoengineering projects raise climatic concerns

On 2 December 2020, the State Council of the People’s Republic of China announced an ambitious plan under which China will develop a “weather modification system” by 2025. According to the press release announcing the plan, the “total area of artificial rainfall (snowfall) operation will reach beyond 5.5 million square kilometers, and for hail suppression it should go beyond 580,000 square kilometers”. This announcement was met with scepticism, caution, and concern in the international media, especially around China’s neighbourhood.

Weather modification is one of the most frequently discussed geoengineering techniques, aimed at tackling climate change impacts. According to multiple academic sources – including Emeritus Professor of Earth System Science John Shepherd’s widely cited September 2009 report Geoengineering the climate: science, governance and uncertainty – geoengineering is “the deliberate large-scale manipulation of the planetary environment to counteract anthropogenic climate change”. However, the report concluded that efforts to reduce global emissions should be a priority and stated, “Nothing now known about geoengineering options gives any reason to diminish these [emissions reduction] efforts.”

With the increase in concerns about climate change in modern society, several countries have begun to invest in research and development of geoengineering technology to mitigate and adapt to climate change events. At the time of writing, there were three broad categories of geoengineering research.

First, carbon dioxide removal includes techniques to capture and remove greenhouse gases from the Earth’s atmosphere. Second, solar radiation management techniques offset greenhouse gas concentrations by causing the Earth to absorb less solar radiation. The most commonly experimented techniques include employing or injecting stratospheric sulfate aerosols, using mirrors in space as ‘sunshades’, marine cloud brightening, and increasing surface reflectivity by whitening rooftops or growing more reflective crops.