Nature – Gan et al. (2026): Asymmetric response of day-to-day temperature variability to CO₂ forcing over Northern Hemisphere mid–high latitudes
Ruyu Gan, Kaiming Hu, Qi Liu, Gang Huang & Suqin Zhang, IN: npj Climate and Atmospheric Science, https://doi.org/10.1038/s41612-026-01372-1
Day-to-day temperature variability (DTDT) quantifies short-term temperature fluctuations and indicates weather-scale variability. Using idealized carbon dioxide removal (CDR) experiments, the authors assess the response asymmetry of DTDT over Northern Hemisphere mid-to-high latitudes under symmetric CO₂ ramp-up (RU) and ramp-down (RD) pathways. DTDT decreases with increasing CO₂ and remains strongly suppressed for about two decades after the CO₂ peak. Comparing CO₂ RU and RD periods with identical CO₂ concentrations, DTDT is systematically weaker during RD than during RU, indicating a pronounced response asymmetry to CO₂ forcing.