The World Meteorological Organization confirmed 2024 as the warmest year on record at about 1.55 degrees Celsius above the pre-industrial level. This has been attributed to climate change caused by greenhouse gas emissions. Traditional solutions, mitigation and adaptation may not be enough to avert the crisis, thus geoengineering.
Consequently, geoengineering proposals have been put forward. However, as scientists and policymakers debate large-scale interventions like Solar Radiation Modification and Carbon Dioxide Removal, could it be our last resort or a dangerous gamble for the global community?
What is Geoengineering?
Geoengineering is the large-scale intervention in the Earth’s oceans, soils, and atmosphere to reduce the effects of climate change. There are two categories of geoengineering techniques: Solar Radiation Modification (SRM) and Carbon Dioxide Removal (CDR).
SRM involves reflecting sunlight away from the Earth or allowing more heat back into space. The proposal involves ideas such as installing giant mirrors that orbit the Earth, spraying sulphate aerosols into the stratosphere, and modifying clouds, plants, and ice to make them more reflective.
The CDR approach extracts CO2 from other gases in the atmosphere by changing it into other forms of carbon through photosynthesis or artificial scrubbing. The separated carbon would then be either sequestered in biomass at the surface or transported away for storage in the ocean or underground.
The Case
Reports estimate that even with drastic cuts in carbon dioxide emissions, more than 1 billion tons of carbon dioxide would need to be removed from the atmosphere per year to hold the average temperature increases from global warming to 1.5 degrees Celsius.
According to David Keith, a professor of applied Physics, Harvard University, we could, with solar geoengineering, keep temperatures under 1.5 degrees Celsius.
“The evidence from all climate models and other analogues is that if one did it in combination with emissions cuts that the climate risk could be reduced in ways that they could not be reduced by emissions cuts alone,” he says.
In this regard, the race to invest in geoengineering has been gearing up over the past decade. For instance, Bill Gates has invested $4.5 million in geoengineering research, signaling his belief that while controversial, it deserves exploration as a method to mitigate climate change.
However, there is skepticism surrounding geoengineering. The UN’s top environmental agency chief, Inger Andersen, warned that a rush into experimental to cool the atmosphere by partially blocking the sun risked harming wildlife, oceans, the ozone layer and crops.
“To look at it purely as a risk-risk within climate, what happens if we do not decarbonise versus what happens if we deploy, climate engineering, is a false narrative for the whole of the global environment,” she said during the United Nations Environmental Assembly held in Nairobi in early 2024 where Nations failed to back a proposal by Switzerland and Monaco for a scientific research group to examine technology to block the sun’s rays.
Geoengineering is also faced with ethical concerns, with some critics arguing that it is an overreach to try and play God. Additionally, ocean fertilization techniques, such as adding iron to stimulate plankton growth, could lead to deoxygenation and the creation of “dead zones,” disrupting marine ecosystems.
Geoengineering is also controversial because modifying a complex and poorly understood global climate system introduces immense uncertainty..
Several studies advocate that rigorous testing should precede the implementation of any geoengineering proposal so that unintended consequences can be avoided.
Read also about Geoengineering projects and Africa’s Potential in CDR.
