01.22.2018
3 New (2018) Papers Link Modern Warming And Past Cooling Periods To High, Low Solar Activity
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Graph Source: Herrera et al., 2015

Graph Source: Russell et al., 2010
1. Oliva et al., 2018
Cold period during 1645–1706 (Maunder solar minimum). Cold period during 1810–1838 (Dalton solar minimum). Warm period during the mid-20th and 21st centuries (modern solar maximum).
2. Ukhvatkina et al., 2018
It is well known that cold and warm periods of the climate are correlated with intensive solar activity (e.g., the Medieval Warm Period), while decreases in temperature occur during periods of low solar activity (e.g., the Little Ice Age; Lean and Rind, 1999; Bond et al., 2001). Long cold periods from 1643 to 1667 and from 1675 to 1690 that were revealed for another territory (Lyu et al., 2016; Wilson et al., 2016) coincided with the Maunder Minimum (1645–1715), an interval of decreased solar irradiance (Bard et al., 2000). The coldest year in this study (1662) was revealed in this period too. The Dalton minimum period centered in 1810 is also notable. … We suppose that a 9-year cycle may be related to solar activity, as, first of all, many authors showed influence of solar activity on the climate variability (Bond et al., 2001; Lean and Rind, 1999; Lean, 2000; Mann et al., 2009; Zhu et al., 2016). Secondly, the significant correlation between of the August–December minimum temperature reconstruction and TSI [total solar irradiance] can be regarded as additional evidence of this assumption. Finally, there is a coincidence of the reconstructed cold periods with the Maunder Minimum (1645–1715) and the Dalton minimum period centered in 1810. The solar activity influence in the region is traditionally associated with an indirect effect on the circulation of the atmosphere (Erlykin et al., 2009; Fedorov et al., 2015). In the second half of the 20th century the solar radiation intensity changes contributed to more intensive warming of the equatorial part of the Pacific Ocean and more active inflow of warm air masses to the north (Fedorov et al., 2015). Close periodicity is revealed in long-term climate reconstructions and is linked to the quasi-200-year solar activity cycle in other studies (Raspopov et al., 2008, 2009). Raspopov et al. (2008) showed that in tree-ring-based reconstructions the cycle varies from 180 to 230 years. Moreover, the high correlation between the minimum temperature reconstructions and TSI, and also the revealed link between the reconstructed temperatures and solar activity minima, lead us to suppose that the solar activity may be the driver of the 200-year cycle. Such climate cycling, linked not only to temperature but also to precipitation, is revealed for the territories of Asia, North America, Australia, the Arctic, and the Antarctic (Raspopov et al., 2008). At the same time, the 200-year cycle (de Vries cycle) may often have a phase shift from some years to decades and correlates not only positively but also negatively with climatic fluctuations depending on the character of the nonlinear response of the atmosphere– ocean system within the scope of the region (Raspopov et al., 2009). According to Raspopov et al. (2009), the study area is in the zone that reacts with a positive correlation to solar activity, though the authors note that we should not expect a direct response because of the nonlinear character of the atmosphere–ocean system reaction to variability in solar activity (Raspopov et al., 2009). Taking into consideration this fact and that the cold and warm periods shown in our reconstruction are slightly shifted compared with more continental areas and the whole Northern Hemisphere, we can say that the reconstruction of minimum August–December temperatures reflects the global climate change process in aggregate with the regional characteristics of the study area.
TSI graph (top) as shown in Blaauw, 2017
3. Lockwood et al., 2018
Space climate and space weather over the past 400 years: 2. Proxy indicators of geomagnetic storm and substorm occurrence During the Dalton minimum [1797-1825] these reconstructions predict an average Ap that is roughly half of that during the modern maximum [1938-2000] but the number of storm-like days (with <Ap>=1dy > Apo) falls radically by an order of magnitude. For the Maunder minimum, the mean Ap is lower than for the modern grand maximum by a factor of about 5 and the reconstructions predict no storm-like days would have been detected. Given the strong correlation between annual means of AE and Ap (r = 0.98), it is not surprising that the reconstructed AE index behaves in a somewhat similar way to Ap, with average values relative to the modern maximum that are roughly halved for the Dalton minimum and a fifth for the Maunder minimum. The number of strong substorm-like hours p.a. in the Dalton minimum [1797-1825] is predicted to have been 140 compared to 512 in the modern grand maximum [1938-2000]. In the Maunder minimum this to falls 28 per annum (i.e. this predicts a total of 1,680 substorm-like hours during the 60 years of the Maunder minimum compared to 30,720 for the 60 years of the modern grand maximum). … Looking to the future, the weakening of Earth’s magnetic moment means that the terrestrial disturbance levels during a future repeats of the solar Dalton and Maunder minima will be weaker and we here quantify this effect for the first time.