“The first modern GSM1 [Grand Solar Minimum] occurs in 2020 – 2053 with the cycle amplitudes reduction to 80% in cycle 25, to 30% in cycle 26 and to 70% in cycle 27 from the maximum amplitude of cycle 24.” − Zharkova et al., 2023
Per a new study, Earth’s Total Solar Irradiance (TSI) has increased by about 1 to 1.5 W/m² from its depths in 1700 to its “maximum amplitude” in cycle 24 (2020). This resulted in a global temperature increase of about 1.5°C during this span.
“[T]he monthly TSI variations (case a) show the increase of TSI by about 1 – 1.3 W/m² in 2020 compared to 1700. This TSI increase found from the S-E distance ephemeris is close to the magnitude of 1 – 1.5 W/m² reported from the current TSI observations.”
But over the next 30 years (2020-2053) Earth will experience a period of significantly reduced solar activity and a consequent “mini ice age” climate that is “similar to the Maunder Minimum” (1645-1715 CE) that characterized the much-colder-than-today Little Ice Age period.
Temperatures will be reduced by about 1°C during the next few decades; Earth will then be only 0.5°C warmer than it was in 1700.
“Because solar irradiance and the terrestrial temperature already increased since the MM [Maunder Minimum] as is clearly recorded from the terrestrial temperature variations, the terrestrial temperature during the first modern GSM1 is expected to drop by about 1.0˚C to become just 0.5°C higher than it was in 1700.”
Image Source: Zharkova et al., 2023
In the study, no anthropogenic or carbon dioxide concentration contribution to terrestrial temperature change is mentioned.