In this exercise, we will focus on the reconstructed temperature series of Central Europe over 2000 years from Luterbacher et al. 2016 and the calculation of extremely warm/cold years. Follow the following text:

• Calculate and plot on a graph of the reconstructed temperature series the extreme years corresponding to the lower and upper 5% quantiles
  
• Quantile - a value that divides a series of ordered numbers into similarly sized parts
  
• quantiles of 5% (lower 5%) and 95% (upper 5%) divide the series into equal numbers of values, i.e. 5% from the beginning and 5% from the end of the series
  
• Download the file Luterbacher_quantities_assignment and open it
• Cell C2 contains a function with the previously calculated quantile threshold (0.919...) for the bottom 5% of quantiles
  
• Extend this cell to the value C 2142
  
• Where the mean air temperature (B2) is lower than the quantile limit, the value "1" appears, otherwise "0"
• A similar procedure applies to the top 5% of quantiles (D2)
  
• Before entering the quantile results into the temperature graph, it is advisable to convert the lower 5% of the quantiles to negative values - the lower 5% negative (E2)
• Add the newly calculated values (columns D, E) to the prepared graph
  

• Based on the temperature trend and the quantiles (extreme temperatures) shown, can you identify significant climate variations over the last 2000 years in central Europe and relate them to significant historical milestones, if applicable?