How does rising atmospheric CO2 affect marine organisms?

Click to locate material archived on our website by topic

Assessing Northern Hemispheric Temperature Trends Via Reconstructed Precipitation Trends in Spain
Rodrigo, F.S., Pozo-Vazquez, D., Esteban-Parra, M.J. and Castro-Diez, Y.  2001.  A reconstruction of the winter North Atlantic Oscillation index back to A.D. 1501 using documentary data in southern Spain.  Journal of Geophysical Research 106: 14,805-14,818.

What was done
The authors note that "to test models ... and detect and attribute climate change," the Intergovernmental Panel on Climate Change (IPCC) "recommends the systematic collection of instrumental and proxy data covering long periods."  Hence, they used a wide variety of documentary data to reconstruct seasonal rainfall in Andalusia (southern Spain) from 1501 to 1997, because "wet/dry periods in Andalusia may be related to cold/warm periods in the Northern Hemisphere."  They then developed a relationship between seasonal rainfall and an index of the North Atlantic Oscillation (NAO) over the period 1851-1997, which they used to reconstruct a history of the NAO from 1501 to 1997.

What was learned
It was found that the NAO influence on climate is stronger in winter than in other seasons of the year in Andalusia, explaining 40% of the total variance in precipitation.  The authors also made a point of noting that "the recent positive temperature anomalies over western Europe and recent dry winter conditions over southern Europe and the Mediterranean are strongly related to the persistent and exceptionally strong positive phase of the NAO index since the early 1980s."

What it means
These several observations would appear to suggest that the entire Northern Hemisphere has experienced "exceptionally strong" positive temperature anomalies since the early 1980s, much like the "unprecedented warming" that is hyped by the IPCC for this period.  However, when the complete record is considered, it can be seen (from the authors' Plate 2) that the first decades of the past century were even more exceptionally positive in this regard than its last decades.  In fact, the early 20th century exhibited by far the most positive NAO index values of the entire 500-year record; and it is abundantly clear that were a linear regression to be run on the 20th century data, the 100-year trend would be decisively downward, indicative of a century-long cooling.  Once again, therefore, red flags continue to be raised with respect to one of the most basic claims of the climate alarmists, i.e., that the 20th century, and especially its last two decades, have experienced warming that is unprecedented over the entire past millennium.