SRM deployment prevents emissions reductions---causes warming, turns the aff, and causes ocean acidification

The year is 2040 and the planet is hot, more than warmer on average than before the start of the Industrial Revolution. Residents of are retreating to higher ground as rising tides encroach on their neighbourhoods. Summer has become synonymous with in Eastern China and violent along the Yangtze River. To mitigate further catastrophe, China and other world powers decide to dim the sun. Once limited to the realm of science fiction, scientists are now considering how to engineer the climate to avert the worst impacts of global warming. has entered mainstream scientific debate in recent years as the window to reduce greenhouse gas emissions narrows. A by the United Nations Intergovernmental Panel on Climate Change (IPCC) shows that by 2040 the global average temperature is projected to exceed 1.5 degrees Celsius above pre-industrial levels. This is the threshold established by the Paris Agreement after which the risk of catastrophic climate impacts increases. If it proves feasible, geoengineering could buy nations some time to decarbonise by temporarily turning down the global thermostat and slowing the impacts of climate change. However, that even researching it creates a moral hazard because it sends a false signal to the public that a hitherto unproven technological fix can be relied on. China is than most countries to extreme weather events linked to a changing climate. The government is focusing on reducing emissions by decarbonising the economy, but it has also launched a to study geoengineering’s potential to mitigate climate change. Although it is still in its infancy, the three-year-old programme raises the question of whether China would deploy solar geoengineering. Uncharted territory Geoengineering involves the deliberate, large-scale intervention in the Earth’s natural systems to counteract climate change. It works in two main ways: blocking sunlight and sucking carbon dioxide out of the atmosphere. Scientists in China have largely focused on techniques to block the sun because they offer the potential to rapidly cool the planet. But they pose risks that require careful study. Solar geoengineering is untested but volcanic eruptions are a natural analogue for one approach. The 1991 eruption of Mount Pinatubo in the Philippines released sulfur dioxide into the atmosphere that formed sulfate aerosols. These scattered sunlight to the extent that the Earth cooled by around from 1992-1993. Scientists have proposed replicating the volcano effect by spraying aerosols out of specially equipped planes at 70,000 feet. This could quickly cool the planet, but it would not target the greenhouse gases that are the source of the problem. The atmosphere would not return to a pre-industrial state because carbon dioxide would continue to acidify the ocean and have other effects on ecosystems. While technologies could, in theory, be employed simultaneously to draw the accumulated gases out of the atmosphere, these technologies are also only just being piloted and .