A time of emergence (TOE) analysis on the impact and uncertainty of global warming on Korean peak summers

In recent years, South Korea has experienced a notable escalation in the intensity and frequency of summer heat. To quantitatively gauge the impact of global warming on Korean summers, this study employs the Time of Emergence (TOE) method, assessing when the effects of global warming surpass natural climate variability. Determining a precise regional TOE is challenging due to disparities between modeled climates and observations. For peak summer seasons (July and August), TOE estimates range from the 2010s to the early 2030s in Shared Socioeconomic Pathways (SSP) 5-8.5, suggesting an imminent or already reached TOE. However, for the same scenario, different methodologies and datasets project the TOE to the late 21st century, suggesting the existence of uncertainty in the TOE. One reason for this uncertainty is the discrepancies identified between climate models and observations, which suggest that climate models could delay the TOE beyond the present time. Furthermore, from 1959 to 2014, global warming accounts for less than 10% of the observed temperature. Despite this, the strengthening of global warming signals is confirmed, leading to the expectation of more extreme events than those seen in the 2018 heat wave. This raises questions about current estimates of TOE and emphasizes the need for robust climate modeling to inform effective climate action.