The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China.

Qunfang Huang,Yuqi Lu

doi:10.3390/ijerph120808773

Abstract

The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (daytime) air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957–2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05). Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001). The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

Highlights

Since the beginning of the industrial revolution, industrial and agricultural activities, such as fossil fuel burning and land use change, have significantly increased the concentrations of greenhouse gases (GHG), such as carbon dioxide (CO2), methane (CH4), ozone (O3), nitrous oxide (N2O), and chlorofluorocarbons [1].For example, since the beginning of the industrial era, the release of CO2 from human activities has resulted in atmospheric CO2 concentrations approximately increasing from 280 ppm to about 392 ppm in 2012 [1].The 2013 IPCC report shows that global surface warming based on land and marine data was approximately 0.85 °C from 1880 to 2012 due to greenhouse effect
The linear fitting of the yearly average, minimal and maximal air temperature vs. year showed that a significant climate warming rate was found for all 41 stations in the Yangtze River Delta urban agglomeration (YRDUA) (Table 2)
Our analysis of daily average, minimal and maximal air temperature observations at 41 stations in the YRDUA over 1957−2010 has revealed significant long-term warming due to the background warming and the urban heat island (UHI)

Summary

Introduction

Since the beginning of the industrial revolution, industrial and agricultural activities, such as fossil fuel burning and land use change, have significantly increased the concentrations of greenhouse gases (GHG), such as carbon dioxide (CO2), methane (CH4), ozone (O3), nitrous oxide (N2O), and chlorofluorocarbons [1].For example, since the beginning of the industrial era, the release of CO2 from human activities has resulted in atmospheric CO2 concentrations approximately increasing from 280 ppm to about 392 ppm in 2012 [1].The 2013 IPCC report shows that global surface warming based on land and marine data was approximately 0.85 °C from 1880 to 2012 due to greenhouse effect. The period of 1983–2012 was very likely the warmest 30-year period of the last 800 years and likely the warmest 30-year period of the last 1400 years [1] Such an increase in air temperature results in rising sea levels, extreme weather events, complex and profound changes in terrestrial and aquatic ecosystems, altered modes of production, and altered lifestyles, forcing humans to adapt [2,3,4]. Because cities contain more than half of the world’s population [2], and because an estimated 70% of the global population is projected to live in cities by 2050 [12], city warming and heat waves due to the UHI effect have a profound impact on the lives, well-being and human health of urban residents [4,13,14]

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Conclusion