Understanding and Adapting to a World with Too Little or Too Much Water

Understanding and Adapting to a World with Too Little or Too Much Water

The recent California drought reduced reservoir water levels and led to state water restrictions.

The recent California drought reduced reservoir water levels and led to state water restrictions.

 

Richard Seager’s work includes integrating paleoclimate and modern records with climate model simulations of the past and future to determine how the combined effects of natural variability and climate change will alter the frequency and intensity of droughts and floods around the globe.

Research at Lamont-Doherty Earth Observatory has shown how droughts as varied as the recent California drought, the Dust Bowl of the 1930s, and the East African droughts of the past decades were ultimately caused by patterns of sea surface temperature anomalies in the tropical oceans. Using extensive simulations with computer models of the climate system and analyses of ocean, atmospheric, and satellite observations, we have identified how subtle changes in tropical ocean temperatures can cause reorganizations of atmospheric circulation, shifting rain bands and storm tracks across the world. By analyzing tree ring records in combination with model simulations of past centuries, we have also shown how past, even more severe “megadroughts” in North America and Asia similarly arose as a consequence of ocean variations.

Understanding past and present drought helps us to better assess future drought risk arising from natural variability. Lamont research is also showing how human-driven climate change is altering drought risk by making wet areas wetter, dry areas drier, shifting rain bands, and drying soils through atmospheric warming. One recent dramatic example shows how climate change intensified a drought in Syria that led to mass migration and became a contributing factor to the onset of civil war.

To ensure that our work can help improves lives, we work closely with water resource managers and experts in development seeking to manage and adapt to changing hydrological conditions. Our goal is to create a world in which water-related hazards are anticipated and adapted to so as to prevent humanitarian crises.  — Richard Seager

Global changes in the Palmer Drought Severity Index for the current century relative to the 20th Century. (Cook et al. 2014)