Question

What is geoengineering? Give two examples.

Short answer

Geoengineering is the deliberate, large-scale intervention in the Earth's natural systems to counteract climate change. Examples include Solar Radiation Management, which involves reflecting sunlight back into space to prevent it from warming the Earth's surface and Carbon Dioxide Removal, which involves capturing and storing CO2 from the atmosphere to slow down and potentially reverse global warming.

Step-by-step solution

Define Geoengineering

Geoengineering, also known as climate engineering, is the deliberate and large-scale intervention in the Earth's natural systems to counteract climate change. In simpler terms, it's the intentional manipulation of the environment, particularly the Earth's climate system, with the aim of lessening the effects of global warming.

Give First Example of Geoengineering

One example of geoengineering is Solar Radiation Management (SRM). This involves reflecting sunlight back into space before it can warm the Earth's surface. One way of doing this is by injecting reflective aerosols into the stratosphere.

Give Second Example of Geoengineering

A second example of geoengineering is Carbon Dioxide Removal (CDR). This involves capturing and storing carbon dioxide from the atmosphere to slow down and potentially reverse global warming. One approach to doing this is through afforestation: converting non-forest land into forest, which will absorb CO2 through photosynthesis.

Key concepts

Climate Engineering

Climate engineering, often synonymous with geoengineering, is a multidisciplinary field focused on large-scale interventions in the climate system as an attempt to combat global warming and mitigate climate change.

Its essence lies in two principal strategies: Solar Radiation Management (SRM) and Carbon Dioxide Removal (CDR). The scientific community considers these operations with caution due to their significant impact on Earth's ecosystems and the potential for unpredictable side effects.

Solar Radiation Management (SRM)

Solar Radiation Management (SRM) seeks to reflect a portion of the sun's energy back into space, thereby reducing the temperature of the Earth.

• Stratospheric Aerosol Injection: This involves introducing particles such as sulfur dioxide into the stratosphere. These particles reflect sunlight, mimicking the cooling effect of large volcanic eruptions.
• Cloud Brightening: By spraying seawater to create more reflective clouds over the ocean, this technique aims to increase the number of droplets in a cloud, making it more sunlight-reflective.

Despite its potential to lower temperatures, researchers emphasize the need for careful consideration as SRM doesn't address the root cause of global warming and could entail climatic changes and disruption in weather patterns.

Carbon Dioxide Removal (CDR)

Carbon Dioxide Removal (CDR) targets the primary greenhouse gas associated with global warming, carbon dioxide (CO2), with the aim of lowering atmospheric CO2 levels.

Methods of CDR include:

• Direct Air Capture: Machines that remove CO2 directly from the atmosphere.
• Enhanced Weathering: Exposing large quantities of minerals that naturally absorb CO2 from the air.
• Bioenergy with Carbon Capture and Storage (BECCS): Generating energy by burning biomass and capturing the emitted CO2 for storage underground.

CDR, in contrast to SRM, addresses the excess carbon concentration problem, but scaling up to the required levels poses economic and logistic challenges.

Global Warming

Global warming is the term used to describe the long-term heating of Earth's climate system observed since the pre-industrial period (between 1850 and 1900) due to human activities, particularly the emission of greenhouse gases.

Consequences of global warming are widespread, including extreme weather events, rising sea levels, and melting ice caps. The global community is seeking to mitigate these effects via emission reduction, adaptation strategies, and exploring geoengineering solutions like SRM and CDR.

Afforestation

Afforestation involves planting trees on land that has not been forested for at least 50 years. This process not only contributes to storing carbon dioxide but also helps in biodiversity conservation, soil preservation, and water cycle regulation.

It's a natural form of CDR because as trees grow, they absorb atmospheric CO2 through photosynthesis. Though afforestation offers many environmental benefits, it requires careful planning to avoid unintended consequences, such as the use of too much water or the introduction of non-native species.

Stratospheric Aerosols

Stratospheric aerosols, tiny particles suspended in the stratosphere, play a critical role in some SRM techniques. Natural occurrences, like volcanic eruptions, release aerosols that cool the planet temporarily.

Artificially, these aerosols can be injected to reflect sunlight away from Earth's surface, in hopes of reducing global warming. The potential outcomes and risks of such interventions are still under scientific scrutiny and debate due to the complexities of climate systems and the potential for unforeseen climatic shifts.