Reconstruction of past climates from documental sources

Valletta, 31st March 2011

Pedro Ribera

Climate and human activities• How can human activities be affected by

weather conditions?

• How (and where and how often) are those situations recorded?

• How can we use that information to rebuild past climates?

• Can this information be used to compare with present conditions or to forecast future climates?

Continental areas

What kind of human activities are affected by weather conditions (and

are registered regularly)?

Agriculture

• Droughts and floodings: what can be done to minimize their impact?

Rogations

• Before European funds for catastrophic events were available, other solutions were to be applied.

Series at different locations• Pro-pluvia rogation series between 16th

century and 19th century.

Drought extension from rogations

Mediterranean

Atlantic

Iberian

Spring agricultural droughts in Spain can be classified in three main groups:

• Mediterranean droughts: simultaneous rogations in Barcelona, Murcia and Zaragoza.

• Atlantic droughts: Sevilla, Toledo and Zamora.

• Iberian droughts: Mediterranean and Atlantic simultaneously.

Climatic analysis

• Mediterranean droughts more frequent than Atlantic.

• Iberian droughts only during the Maunder minimum (low solar activity, 1645-1715)

Sun activity (sun spots)

Year

Domínguez-Castro F., R. García-Herrera, P. Ribera, and M. Barriendos. ‘A shift in the spatial pattern of Iberian droughts during the 17th century’. Climate of the Past, 6, 53-63. doi:10.5194/cp-6-553-2010. 2010.

Rogations anywhere else?

• Regional analysis could be extended over a bigger area with more rogation series from other locations.

• Possibly other Catholic Mediterranean countries?

The oceans

The world oceans were crowded with sailing ships from different European

powers since the 16th century.

Antonio de Ulloa Jorge Juan

Documental records

We began this voyage with ‘galeno wind’….

High resolution data (even daily)

Gallego, D. García-Herrera, R., Ribera, P. y Jones, P.D. 2005: Seasonal mean pressure reconstruction for the North Atlantic (1750-1850) based on early marine data, Climate of the Past, 1, 19-33.

SLP reconstruction 1750-1850N

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The Mediterranean

• English logbooks for the 1750-1850 period, over the Mediterranean, are being digitised and analysed.

• Information could be obtained for a previous period from English archives.

• Other sources?

Summary• Records about different human activities have

proven to be a valuable instrument to rebuild the climate of the past, to compare it with the present climate and to suggest possible future climate conditions.

• Many archives are yet to be analyzed (mostly small ones).

• Archives from outside Europe have not been explored.

• North African records could include valuable information from before the 16th century.