The annual average near-surface global temperature will temporarily exceed 1.5 °C between 2023 and 2027. If this level is irrevocably exceeded, the functions of marine biodiversity, fisheries, and ecosystems may no longer be maintained. In light of this fact, this paper examines whether a shock-like (rapid and substantial) increase in the proportion of renewable energy sources could result in a precipitous reduction in greenhouse gas emissions. In order to accomplish this, the paper analyzes the magnitude and direction of the asymmetric and symmetric impacts of renewables on CO2 emissions, which represent shock-like and ordinary changes, respectively. Second, the paper examines whether there is a functional complementarity between major renewables in reducing CO2 emissions, and whether this complementarity increases when renewables experience asymmetric shocks. The conclusion of the paper is that the negative impact of renewables on CO2 emissions either (i) remains unchanged when they experience asymmetric shocks or (ii) increases by 60–260 percent or 100 percent, respectively, when they experience these shocks simultaneously or separately, respectively. The paper makes two recommendations to prevent the persistent exceeding of 1.5 °C. First, policymakers should intensify their efforts to rapidly and substantially increase renewable energy consumption in total. Second, they should accomplish this increase in all renewable sources in a balanced fashion so as to maximize their carbon-reduction effects by functionalizing their green complementarities.