A peer-reviewed climate study compares spring drought linked to the Pacific Decadal Oscillation in modern conditions and the Last Glacial Maximum. The affected area expands in East Asia and North America as atmospheric circulation shifts. This is a comparison of modelled climate states and observed relationships, providing a physical mechanism rather than a local forecast.
The area of spring drought associated with the Pacific Decadal Oscillation was larger in modern-climate simulations than in simulations of the Last Glacial Maximum. The peer-reviewed comparison found increases of 160 per cent in East Asia and 57 per cent in North America. East Asia’s additional area was about 470,000 square kilometres; North America’s was about 960,000 square kilometres.[1]
This ocean oscillation involves changing conditions in the Pacific. Researchers combined reanalysis observations with atmosphere and climate models to examine its negative phase. Changes in moisture transport were linked to two circulation features: the North American subtropical trough and the India–Burma trough. Their shifts redistributed the geographical concentration of rainfall responses.[1]
The older climate state represents conditions about 21,000 years ago. Ice sheets, carbon dioxide and other background conditions differed from today, complicating attribution to temperature alone. Errors in the models’ circulation geometry and ocean–atmosphere coupling also constrain the findings. The study tests a physical mechanism across climate states; its regional percentages describe that comparison rather than future drought rates for individual cities.[1]
