Solar Activity: Cycle 25 Surpasses Cycle 24

by J. Vinos, Jul 6, 2023 in WUWT


Over the past two decades, solar activity has been characterized by an extended solar minimum spanning two solar cycles, known as the Clilverd Minimum. This phenomenon is currently affecting the climate, but before we can understand its impact, we must address the significant discrepancy between the solar effects observed in paleoclimate proxy records and modern observations. The relationship between solar signals and climate response is complex and not fully understood. However, there is substantial evidence from models and reanalyses that the relationship exists. A recent hypothesis is that the solar signal modulates heat and moisture transport to the Arctic, which explains its relatively small effect during a single solar cycle. However, when an anomaly in solar activity persists over several cycles, as it did during the 70-year modern solar maximum, its effect accumulates and has a large impact on the planet’s energy budget. Understanding this mechanism is critical to understanding the overall impact of solar activity on our climate.

Current Solar Activity

The monthly sunspot number for June 2023 reached 163.4. While this figure may be revised slightly, it’s likely to stand as the highest number seen in over two decades, since September 2002. Solar Cycle 25 is relatively young, only three and a half years old, which means there are ample opportunities over the next three years to surpass this month’s 20-year record. Based on recent data, it seems very likely that Solar Cycle 25 will surpass Solar Cycle 24 in terms of activity.

Figure 1. Daily and monthly sunspot numbers over the past 13 years, as provided by SILSO.