Iilmastonsäätelymenetelmät

Iilmastonsäätelymenetelmät, often referred to as geoengineering, encompass a range of deliberate, large-scale interventions in the Earth's climate system to counteract climate change. These methods are broadly categorized into two main approaches: solar radiation management (SRM) and carbon dioxide removal (CDR).

Solar radiation management techniques aim to reflect a portion of incoming sunlight back into space, thereby reducing the amount of heat absorbed by the Earth. Examples include stratospheric aerosol injection, which involves releasing reflective particles into the upper atmosphere to mimic the cooling effect of large volcanic eruptions, and marine cloud brightening, which aims to increase the reflectivity of clouds over oceans by spraying sea salt aerosols. Other SRM concepts include space-based reflectors and modifying the Earth's surface albedo, such as by painting roofs white.

Carbon dioxide removal methods focus on extracting carbon dioxide from the atmosphere and storing it permanently. These techniques aim to reduce the concentration of greenhouse gases that are driving global warming. Examples include afforestation and reforestation, which involve planting trees, and bioenergy with carbon capture and storage (BECCS), which combines biomass energy production with carbon capture technology. Direct air capture (DAC) technologies are also being developed to chemically remove CO2 directly from ambient air. Ocean fertilization, which aims to stimulate the growth of phytoplankton to absorb CO2, is another proposed CDR method, though it carries significant ecological risks.

The development and potential deployment of ilmastonsäätelymenetelmät are subjects of ongoing research and considerable debate. While they offer the theoretical possibility of mitigating some of the worst impacts of climate change, significant uncertainties and potential risks remain regarding their effectiveness, scalability, side effects, governance, and ethical implications.