A paper published today by the journal Proceedings of the National Academy of Sciences (PNAS) by scientists at the University of New Mexico posits that future global warming may produce above average monsoonal moisture. The extra moisture will most likely be counterbalanced by increased evaporative loss.
The scientists discovered that during the late Holocene era, the North American climate was punctuated by periods of long aridity intervals called megadroughts. They are linked to cool Northern Hemisphere temperatures and sea surface temperatures in the North Atlantic.
During the last millennium, megadroughts were prevalent, and there was even a multi-century drought, called Super Drought, that lasted for more than 300 years. The Super Drought corresponds to the coldest period of the Little Ice Age. New research is showing that suggests megadroughts were hemispheric in scale.
The past 1,500 years are of particular importance to researchers, including the Medieval Climate Anomaly and Little Ice Age, because this period had much natural climate variability before the large addition of greenhouse gases from human burning of fossil fuels. These natural fluctuations in climate represent important points of validation for models of future climate change.
This research allows scientists to develop more accurate climate models to determine atmospheric climate anomalies while developing a deeper understanding of the future of climate change.
Given future warming due to increases in greenhouse gases increases in moisture from increase in summer precipitation may be wiped out by increase in evaporation. Increases in precipitation in more humid regions may lead to increases in effective moisture.