Compound climate-pollution extremes in Santiago de Chile

Abstract

Cities in the global south face dire climate impacts. It is in socioeconomically marginalized urban communities of the global south that the effects of climate change are felt most deeply. Santiago de Chile, a major mid-latitude Andean city of 7.7 million inhabitants, is already undergoing the so-called “climate penalty” as rising temperatures worsen the effects of endemic ground-level ozone pollution. As many cities in the global south, Santiago is highly segregated along socioeconomic lines, which offers an opportunity for studying the effects of concurrent heatwaves and ozone episodes on distinct zones of affluence and deprivation. Here, we combine existing datasets of social indicators and climate-sensitive health risks with weather and air quality observations to study the response to compound heat-ozone extremes of different socioeconomic strata. Attributable to spatial variations in the ground-level ozone burden (heavier for wealthy communities), we found that the mortality response to extreme heat (and the associated further ozone pollution) is stronger in affluent dwellers, regardless of comorbidities and lack of access to health care affecting disadvantaged population. These unexpected findings underline the need of a site-specific hazard assessment and a community-based risk management.

Extreme fire weather in Chile driven by climate change and El Niño–Southern Oscillation (ENSO)

“…Climate change is worsening fire weather by making hot and dry conditions more frequent. While the climate-induced signal of excess heat emerged in Central Chile just in the last decade 23 , 24 , some locations in our study area have been experiencing prolonged drying for nearly 40 years 21 , 22 . The deteriorating situation in Central Chile has been worsened by a megadrought, which since 2008 20 has lowered reservoirs and caused tensions over water and may have facilitated larger fires.…”

“…Climate extremes are likely boosting fire activity in Central Chile (30°–39° S). The loss of precipitations observed during the last four decades 21 , 22 has been worsened by intense heatwaves 23 , 24 , which have favored large and high-intensity wildfires in Central Chile. Over 90% of the wildfires in the country occur in this zone, which exhibits a pronounced north–south gradient in precipitation (Fig.…”

Air quality and urban climate improvements in the world’s most populated region during the COVID-19 pandemic

“…However, the air quality (AQ) in urbanized areas is often unhealthy. Pollutants such as fine particulate matter (PM 2.5 ), ozone (O 3 ), and nitrogen oxides (NO x ) lead to respiratory and other diseases and are important causes of morbidity and mortality (Schraufnagel et al 2019, Fuller et al 2022, Feron et al 2023. Increasingly strict emission control strategies aimed at reducing air pollution have been implemented worldwide over the past several decades, following international guidelines.…”