In the 2015 Paris Agreement, 195 countries have committed to keep global average temperature rise to well below 2°C above pre-industrial levels and to pursue efforts for a lower target of 1.5°C. However, the current greenhouse gas (GHG) has already exceeded 40 Gt CO2 per year, and the various recent studies agree that current efforts laid out in countries’ Nationally Determined Contributions (NDCs) are not enough and there remains a huge gap between the NDCs and the required GHG emissions reductions for the 2°C, much less the 1.5°C, target. Current NDCs would still likely lead to a global warming of up to 3.8°C in 2100. One of the most critical consequences of global warming is Sea Level Rise (SLR). The IPCC Fifth Assessment Report (AR5) projected a global SLR of up to 98 cm in 2100, but more recent studies suggested that eventual global SLR could reach up to 4.3 - 9.9 m due to the collapse of ice sheets. This is a sobering warning especially for coastal cities and low-lying areas that would be threatened by inundation and flooding from SLR. A recent study has also estimated that for a SLR of 123 cm, without adaptation, up to 4.6% of global population is expected to be flooded annually in 2100 with expected annual losses of up to 9.3% of global GDP. A higher SLR would certainly impact even more people and cause even greater losses. Thus, the climate change policies have not only to be focused on mitigation, but also more attention needs to be given to adaptation to prevent the losses.
Instead of taking mitigation and adaptation as two independent policies, in this paper we propose a climate change policy based on a synergy between mitigation and adaptation. One potential example for achieving this synergy is through carbon mineralization (CM). CM has the capacity to sequester gigatonne-levels of CO2, while producing solid materials, such as mineral carbonate and silica, which can be used for land reclamation purposes or construction of dikes and raised river banks to protect against SLR and flooding. Thus, CM creates a synergy between mitigation and adaptation by sequestering significant amounts of CO2 resulting in global benefits, meanwhile providing construction materials to vulnerable areas for local adaptation against SLR. In this paper, the costs of CM and synergy between mitigation and adaption, as well as its benefits of protecting against the damage of SLR, will be discussed respectively. The feasibility of implementing this synergy policy will depend on the cost-effectiveness of mitigation and adaptation, making them more attractive to all stakeholders.