Unusual activity of the Sun during recent decades compared to the previous 11,000 years

By S. Solanki, I. Usoskin, B. Kromer, M. Schüssler, J. Beer. Nature, 2004

930 citations recorded by the source corpus.

Direct observations of sunspot numbers are available for the past four centuries, but longer time series are required, for example, for the identification of a possible solar influence on climate and for testing models of the solar dynamo. Here we report a reconstruction of the sunspot number covering the past 11,400 years, based on dendrochronologically dated radiocarbon concentrations. We combine physics-based models for each of the processes connecting the radiocarbon concentration with sunspot number. According to our reconstruction, the level of solar activity during the past 70 years is exceptional, and the previous period of equally high activity occurred more than 8,000 years ago. We find that during the past 11,400 years the Sun spent only of the order of 10% of the time at a similarly high level of magnetic activity and almost all of the earlier high-activity periods were shorter than the present episode. Although the rarity of the current episode of high average sunspot numbers may indicate that the Sun has contributed to the unusual climate change during the twentieth century, we point out that solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades.

Subfields: Astronomy and Astrophysics, Molecular Biology, Oceanography

View Paper: https://www.semanticscholar.org/paper/58c67c1c7428d2088384f2befb2dd8416abd4859

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Molecular Biology

In Oceanography

Citations in the corpus

Solar Forcing for CMIP6 (v3.1) (2016, background): “It is noteworthy that the Sun was more active during recent decades (the modern grand maximum) than during most of the other periods (Solanki et al., 2004).”
Global Catastrophic Risks (2008, methodology): “This has been used to reconstruct solar activity during the past 8000 years, after verifying that it correctly reproduces the number of sunspots during the past 400 years (Solanki et al., 2004).”
A History of Solar Activity over Millennia (2008, methodology): “93 with the RMS deviation between the two series being six for the period of 1610 – 1900 (Solanki et al., 2004).”
Evolution of the solar irradiance during the Holocene (2011, methodology): “…are based on the assumption that carbon cycle parameters have not changed significantly throughout the Holocene, which may not be exactly valid, particularly in the early Holocene, as discussed previously by Solanki et al. (2004), Ellison et al. (2006), Usoskin et al. (2007, 2009), and others.”
Climate and carbon-cycle variability over the last millennium (2010, methodology): “The TSI time series for the period 800 AD to the Maunder Minimum is reconstructed from estimates of the solar open magnetic flux based on cosmogenic isotope 14C concentrations in tree rings (Solanki et al., 2004; Krivova and Solanki, 2008; Usoskin et al., 2007).”
SOLAR INFLUENCES ON CLIMATE (2010, neutral): “16 The connection between GCR and TSI is another method for reconstructing TSI, with the potential to encompass recent millennia using cosmogenic isotope measurements (Usoskin et al. 2003; Solanki et al. 2004).”
A New Calibrated Sunspot Group Series Since 1749: Statistics of Active Day Fractions (2015, background): “…that the sunspot activity (quantiﬁed as the number of groups) was somewhat higher in the mid-eighteenth century than it was in the mid-nineteenth century, but signiﬁcantly lower than the Modern Grand Maximum (Usoskin et al. , 2003; Solanki et al. , 2004) in the second half of the twentieth century.”
Revisiting the Sunspot Number (2014, background): “ult to establish given the scarcity of observations over that period.Still, the vanishing upward trend over the last 250 years questions the existence of a modern “Grand Maximum” in the 20th century (Solanki et al. 2004, Abreu et al. 2008, Usoskin et al. 2012, 2014), which resulted primarily from th”
Grand minima and maxima of solar activity: new observational constraints (2007, methodology): “A comparison between the sunspot number series obtained using the new open flux model with those published by Solanki et al. (2004) is shown in Fig.”
A reconstruction of radiocarbon production and total solar irradiance from the Holocene 14 C and CO 2 records: implications of data and model uncertainties (2013, methodology): “Solanki et al.(2004) suggests that solar activity is unusually high during recent decades compared to the values reconstructed for the entire Holocene.”
Solar Irradiance Variability and Climate (2013, methodology): “This was put to use by Usoskin et al. (2003b), who reconstructed sunspot number for the last 1000 years, and by Solanki et al. (2004), who did that for the last 11400 years, i.e. basically the full holocene.”
Reconstruction of the Sunspot Group Number: The Backbone Method (2015, result): “…appears to reach and sustain for extended intervals of time the same level in each of the last three centuries since 1700 and that the past several decades do not seem to have been exceptionally active, contrary to what is often claimed: “most active in 8,000 years” (e.g. Solanki et al., 2004).”
Heliospheric modulation of cosmic rays: Monthly reconstruction for 1951–2004 (2005, background): “At very long timescales it can be studied, e.g., by cosmogenic isotopes [see, e.g., Masarik and Beer, 1999; Usoskin et al., 2003; McCracken et al., 2004a; Solanki et al., 2004].”