Occurrence and persistence of future atmospheric stagnation events

• Published in: Nature climate change Vol. 4; no. 8; pp. 698 - 703
• Main Authors: Horton, Daniel E., Skinner, Christopher B., Singh, Deepti, Diffenbaugh, Noah S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2014; Nature Publishing Group
• Subjects: 704/106/35/823; 704/106/694/2739/2807; Air quality; Air. Soil. Water. Waste. Feeding; Anthropogenic factors; Applied sciences; Atmospheric circulation; Atmospheric pollution; Biological and medical sciences; Climate Change; Climate Change/Climate Change Impacts; Climate models; Climatology. Bioclimatology. Climate change; Earth, ocean, space; Environment; Environment. Living conditions; Environmental Law/Policy/Ecojustice; Exact sciences and technology; External geophysics; Global warming; Hydrologic cycle; letter; Medical sciences; Meteorology; Pollutants; Pollution; Pollution control; Pollution levels; Public health; Public health. Hygiene; Public health. Hygiene-occupational medicine; Tropical environments; Mexico; India; Multimodel; Atmospheric circulation; Coupled model; Atmospheric condition; General circulation models; Stagnation; climate warming; Environmental factor; Air quality; Climate models; Dynamical climatology; Climate change; Air flow; Health and environment; Global change; Planetary scale; Air pollution; Public health
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/nclimate2272

Atmospheric stagnation can have serious health implications due to increased pollution exposure. This study investigates how global warming will alter atmospheric circulation and the resulting changes in the frequency and persistence of stagnation events. The authors find an overall increase in the size of the population exposed to these events and highlight the need to evaluate air pollution management. Poor air quality causes an estimated 2.6–4.4 million premature deaths per year 1 , 2 , 3 . Hazardous conditions form when meteorological components allow the accumulation of pollutants in the near-surface atmosphere 4 , 5 , 6 , 7 , 8 . Global-warming-driven changes to atmospheric circulation and the hydrological cycle 9 , 10 , 11 , 12 , 13 are expected to alter the meteorological components that control pollutant build-up and dispersal 5 , 6 , 7 , 8 , 14 , but the magnitude, direction, geographic footprint and public health impact of this alteration remain unclear 7 , 8 . We used an air stagnation index and an ensemble of bias-corrected climate model simulations to quantify the response of stagnation occurrence and persistence to global warming. Our analysis projects increases in stagnation occurrence that cover 55% of the current global population, with areas of increase affecting ten times more people than areas of decrease. By the late twenty-first century, robust increases of up to 40 days per year are projected throughout the majority of the tropics and subtropics, as well as within isolated mid-latitude regions. Potential impacts over India, Mexico and the western US are particularly acute owing to the intersection of large populations and increases in the persistence of stagnation events, including those of extreme duration. These results indicate that anthropogenic climate change is likely to alter the level of pollutant management required to meet future air quality targets.