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One of the limits of climatology is that we only have about a hundred years of scientifically gathered weather data, and we know that they don’t give us the full story. Paleoclimatologists find ways to figure out what the weather was like before we had thermometers, rain gauges, and written records. The natural world has recorded its own stories in tree rings, lake sediments, ice, cave deposits, and fossils, and paleoclimatologists can put that information together to assemble thousands of years of climate history.

The findings of paleoclimatology show that past droughts have been more severe and have lasted even longer than the Dust Bowl in the 1930s or drought in the 1950s – by centuries, in some cases. Paleoclimatology helps us understand the full range of natural variability.


desert landforms with sparse vegetation
An examination of how scientists reconstruct the history of Earth’s climate over hundreds of thousands—in some cases millions—of years.
chart of reconstructed annual rainfall over centuries in western New Mexico
Data include geophysical and biological measurement time series, with a list of links to datasets, projects and perspectives about paleoclimatology, including ways to contribute data, education, and outreach.
large river between canyon walls
Selected research papers, reports, and other resources which show the current state-of-knowledge on the variability of climate and hydrology in the Colorado River Basin.
logo of Climates Assessment for the Southwest (CLIMAS)
How scientists use “climate proxies” to reconstruct past events.
Example image of tree rings
LBDP is a recalibrated data series of June-July-August Palmer Modified Drought Index (PMDI) values by United States climate division, compiled by blending tree-ring reconstructions and instrumental data from the coterminous United States. Using tree-ring PMDI reconstructions to extend the instrumental record yields a record of drought distribution and intensity covering over 2000 years.