English
Revolution (1640-1660)
The “Fronde” (1648-1653)
Thirty Years’ War (1618-1648)
“Little Ice Age”
Potosí
“Venality of Office”
Comparison of
proxy-based Northern Hemisphere (NH) temperature reconstructions [Jones
et al., 1998; Mann et al., 1999; Crowley and Lowery, 2000] with model
simulations of NH mean temperature changes over the past millennium
based on estimated radiative forcing histories [Crowley, 2000; Gerber
et al., 2002--results shown for both a 1.5°C/2*CO2 and
2.5°C/2*CO2 sensitivity; Bauer et al., 2003). Also shown are two
independent reconstructions of warm-season extratropical continental NH
temperatures [Briffa et al., 2001; Esper et al., 2002] and an extension
back through the past two thousand years based on eight long
reconstructions [Mann and Jones, 2003]. All reconstructions have been
scaled to the annual, full Northern Hemisphere mean, over an
overlapping period (1856-1980), using the NH instrumental record [Jones
et al., 1999] for comparison, and have been smoothed on time scales of
>40 years to highlight the long-term variations. The smoothed
instrumental record (1856-2000) is also shown. The gray/red shading
indicates estimated two-standard error uncertainties in the Mann et al.
[1999] and Mann and Jones [2003] reconstructions. Also shown are
reconstructions of ground surface temperatures (GST) based on
appropriately areally-averaged [Briffa and Osborn, 2002; Mann et al.,
2003] continental borehole data [Huang et al., 2000], and hemispheric
surface air temperature trends, determined by optimal regression [Mann
et al., 2003] from the GST estimates. All series are shown with respect
to the 1961-90 base period. . Image source: NOAA.
The main figure shows eight records of local temperature variability on multi-centennial scales throughout the course of the Holocene, and an average of these (thick dark line) to 10,000 BCE (from 12,000 BP to the present). The records are plotted with respect to the mid-twentieth century average temperature, and the global average temperature in 2004 is indicated. An inset plot compares the most recent two millennia of the average to other recent reconstructions. At the far right of this plot it is possible to observe the emergence of climate from the last glacial period of the current ice age. During the Holocene itself, there is general scientific agreement that temperatures on the average have been quite stable compared to fluctuations during the preceding glacial period. Because of the limitations of data sampling, each curve in the main plot was smoothed (see methods below) and consequently, this figure can not resolve temperature fluctuations faster than approximately 300 years. Further, while 2004 appears warmer than any other time in the long-term average, and hence might be a sign of global warming, it should also be noted that the 2004 measurement is from a single year (actually the fourth highest on record). It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the available resolution. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot.
Social
Disciplining
in the ‘Iron Century’ 
