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. 2022 May;66(5):911-925.
doi: 10.1007/s00484-022-02248-8. Epub 2022 Mar 24.

Increasing trees and high-albedo surfaces decreases heat impacts and mortality in Los Angeles, CA

Laurence S Kalkstein  1 , David P Eisenman  2 , Edith B de Guzman  3 , David J Sailor  4
Affiliations

Increasing trees and high-albedo surfaces decreases heat impacts and mortality in Los Angeles, CA

Laurence S Kalkstein et al. Int J Biometeorol. 2022 May.

Abstract

There is a pressing need for strategies to prevent the heat-health impacts of climate change. Cooling urban areas through adding trees and vegetation and increasing solar reflectance of roofs and pavements with higher albedo surface materials are recommended strategies for mitigating the urban heat island. We quantified how various tree cover and albedo scenarios would impact heat-related mortality, temperature, humidity, and oppressive air masses in Los Angeles, California, and quantified the number of years that climate change-induced warming could be delayed in Los Angeles if interventions were implemented. Using synoptic climatology, we used meteorological data for historical summer heat waves, classifying days into discrete air mass types. We analyzed those data against historical mortality data to determine excess heat-related mortality. We then used the Weather Research and Forecasting model to explore the effects that tree cover and albedo scenarios would have, correlating the resultant meteorological data with standardized mortality data algorithms to quantify potential reductions in mortality. We found that roughly one in four lives currently lost during heat waves could be saved. We also found that climate change-induced warming could be delayed approximately 40-70 years under business-as-usual and moderate mitigation scenarios, respectively.

Keywords: Climate health; Extreme heat; Heat-related illness; Urban cooling; Urban greening; Urban heat island.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Years of delay of climate change–induced warming under the four albedo/canopy cover scenarios. Bars indicate the number of years of delay that would result from each case under either RCP 8.5 or 4.5
Fig. 2
Fig. 2
Root mean square error (RMSE) for the July 2006 Excess Heat Event (EHE). (a) RMSE July 2006 EHE for BUR and (b) RMSE July 2006 EHE for KCQT. Simulated versus observed air temperature shows the model performance (measured by RMSE) is 2.9 and 2.0 °C for Burbank and KCQT weather stations, respectively
Fig. 3
Fig. 3
Root mean square error (RMSE) for the August 2009  Excess Heat Event (EHE). (a) RMSE Aug 2009 EHE for BUR and (b) RMSE Aug 2009 EHE for  KCQT. Simulated versus observed air temperature shows model performance (measured by RMSE) is 2.4 and 2.0 °C for Burbank and KCQT weather stations, respectively
See this image and copyright information in PMC

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