Since the industrial revolution, human ingenuity has provided the foundation for technological innovation, which in turn has driven economic development on an unprecedented level. Conversely, this ingenuity and scientific insight have allowed us to understand the impact this development is having on the natural environment. Now we must employ this asset to meet the challenges that society now faces.
Using fossil fuels to provide the energy to drive our rapid development and industrialisation, we have unwittingly unleashed our biggest threat: climate change. Projections from the Intergovernmental Panel on Climate Change (IPCC) suggest that increasing global temperatures are accelerating the melting of ice sheets, increasing sea level rise and putting low-lying coastal areas in danger. Warming is also connected with changing rainfall patterns, more intense tropical cyclones, and ecological effects such as coral bleaching. But perhaps the greatest danger for human civilisation is the threat from positive feedback cycles. These are effects of climate change that cause further climate change, such as the melting permafrost causing the release of methane. As the Earth warms, the risk of triggering such cycle’s increases.
Many parts of the world are likely to become uninhabitable even under medium carbon dioxide (CO2) emission scenarios, through desertification, droughts, and rising sea level; plus the added stress of a population of 9 billion by 2050. This will have considerable effects on the health and prosperity of the population, particularly in developing countries, which will experience disproportionately severe impacts whilst having the fewest resources to adapt. For sustainable development across nations to be realistic, climate change needs to be dealt with urgently. Despite ongoing political negotiations, a rapid reduction in emissions is unlikely. Thus increasing consideration is needed for geoengineering – i.e. the use of engineering and technology to limit and reverse the effects of climate change.
Geoengineering will involve the large-scale engineering of our environment with the aim of combating and counteracting the continued emissions of greenhouse gases (GHGs) into the atmosphere. Depending on if the aim is to mitigate or reverse the changes, there are two main geoengineering options that are being developed.
The first is Carbon Dioxide Removal (CDR). CDR involves removing GHGs from the atmosphere, thus attempting to shift the atmospheric composition back toward pre-industrial values. Examples include reforestation, iron fertilisation to enhance oceanic uptake of CO2 and the much-publicised technique of carbon capture and storage. However, CDR techniques reduce concentrations gradually and are expected to be longer-term solutions.
Solar Radiation Management (SRM) techniques, meanwhile, can be used for short-term mitigation. They work relatively quickly so could be implemented if we face ‘runaway climate change’. SRM techniques aim to reduce the Earth’s absorption of solar radiation to counterbalance the energy trapped by increased concentrations of GHGs. Possible techniques include injecting aerosols into the atmosphere and brightening clouds by spraying salt water. Other SRM methods include constructing a solar deflector in space, and placing mirrors in a near-Earth orbit. However, these are expensive and unproven techniques. As well as the financial implications, SRM techniques only lessen the effects of climate change and fail to address other problems that elevated atmospheric CO2 has on earth systems, such as ocean acidification.
Impacts on development
Our society has been slow to react to the necessary changes in lifestyle needed to reduce GHG emissions rapidly. Fossil fuels have provided us with cheap accessible energy but are finite; combined with the effects of climate change, this could threaten energy, food and water security. Geoengineering could provide a transitional period for shifting our society off depleting fossil fuel reserves to carbon neutral ‘green’ technologies (solar power, wind energy generation, algal bio-fuels), thus allowing future sustainable development to continue.
Science has enabled the development of geoengineering techniques, but their implementation will require both innovative technology and engineering skills. In the short-term, these technologies can be used to reduce and delay the worst impacts of climate change, giving developing countries in particular more time to develop and improve their resilience to changes in the climate.
Geoengineering is therefore an excellent example of how engineering and technology are essential for future development. Ignoring these options could leave humanity struggling to maintain our current standard of living, let alone moving forward into a sustainable and fossil fuel free society.
As we realise the effects of our rapid development, we must act quickly and decisively to reduce its impact. And so, ironically, although human ingenuity has led us to this point, it will be this asset that saves us.