The 1690's: a cold decade in Scotland

The 1690's: a cold decade in Scotland

The EOS article How the Cold Climate Shaped Scotland’s Political Climate presents the results of tree ring data analysis supporting historic accounts of anomalously cold weather during the 1690s.

For some context, I present some analysis of the Central England temperature data that consists of daily temperatures measured from 1659 until the present. The record reveals some unique aspects of the 1690s cold snap. The EOS article suggests this cold spell led to Scotland's failed attempt to colonize the Darien region of Panama and to its union with England. The article notes "The colony’s failure (to colonize the Darien region) left Scotland in an even worse economic situation and helped trigger the Acts of Union with England. The average annual temperatures (Figure 1) reveal this anomalous period of low temperatures in the late 1600s.

Figure 1: Smoothed July (red), average annual (green) and January (blue) temperature comparison

A magnified view of the average July and January temperatures (Figure 2) reveals that the last of the 1600s is unusual in that temperatures in both the summer and winter dropped during the 1690s. The EOS tree ring data reveals narrow growth rings during the 1690s. The temperature data reveals this is consistent with the colder summer temperatures. I don't have temperatures for Scotland during this period, but we can imagine that they may have been cooler than in central England to the south.

Figure 2: Comparison of smoothed July temperatures (red) and January temperatures (blue).

A plot of the residual July and January temperatures together (Figure3) emphasizes some of these differences through time. Note that the juxtaposition of colder summers and winters is unique to this time.

Figure 3: Residual smoothed temperatures for January (blue),July (pink) and average annual (green)

The paper "Complexity in crisis: The volcanic cold pulse of the 1690s and the consequences of Scotland's failure to cope" shows temperature reconstruction of July to August temperatures from 1200 to present for Scotland (Figure 4).

Figure 4: July to August temperature reconstruction. The blue dots note the colder summers. The yellow line is a 20 year low pass filtered version of temperature variations.

I would suggest that it is this combination of colder winters and summers that led to the hardships in Scotland during the late 1690s.