As heat waves become more frequent, so do heat-related deaths and illnesses. Many studies have found a direct correlation between rising temperatures and conditions such as heat rashes, heat exhaustion, cardiovascular and respiratory diseases, as well as fatalities. Heat waves in urban areas are even more severe, characterized by greater intensity and longer duration due to urbanization, particularly the urban heat island effect (UHI) which alters the thermal balance of the built-up area such that temperatures are higher than in the surrounding environment. Building and ground cover materials like concrete and asphalt selectively absorb and store heat, leading to elevated temperatures compared to those observed in areas with vegetation or water bodies – and anthropogenic heat emissions across the city also contribute to the UHI intensity.
Thus increased heat can make cities climatically uncomfortable and pose health risks, especially during heat waves, but these risks are not geographically homogenous. A particular hot-spot for both global and local warming is the eastern Mediterranean basin, which is located at the transition from the warm sub-humid regions of southern Europe to the hyper-arid deserts of the middle east. At the center of this transition zone is the Negev desert of southern Israel, which is at the forefront of these climate change challenges. This arid region is particularly vulnerable, as its unique ecosystem and urban populations are under increasing pressure from rising temperatures, potentially leading to higher rates of illness and mortality. With over 90% of Israel's population living in urban areas, including cities in the Negev like Be'er Sheva, the impact of heat on public health is a critical concern. Despite this urgency, comprehensive research on the relationship between urban heat and health outcomes in this region remains limited. This gap in knowledge underscores the need for immediate attention from health authorities and research institutions to address the specific climate-related health risks faced by residents of the Negev and other urban areas in Israel.
Many research studies around the world have found a strong correlation between heat waves and morbidity and mortality rates, and particularly a rise in cardiovascular diseases. For example, a study carried out in seven major cities in the U.S. used multidecadal, geographically referenced medical records to identify high-risk zones for extreme heat events. The study found that during the study period, days with high temperatures were connected to an increase in mortality in six major cities. The same results were found in another study in New York, where places with lower socioeconomic status had fewer green areas than other neighborhoods in NY and experienced temperatures 2 degrees Celsius higher. Another study was conducted in Dallas, Texas and Phoenix, Arizona. By combining Landsat 8 imagery and socioeconomic data, they found strong correlations between lower socioeconomic status, lower vegetation cover and higher temperatures.
Since the 1960s, the Mediterranean region has experienced a notable rise in temperatures, accompanied by a marked increase in the occurrence, severity, and length of heat waves. The summers in Israel have become noticeably warmer and longer with a decrease in cool nights. According to the Israel Climate Change Information Center, temperatures in Israel have risen by 1.4 degrees Celsius between 1950-2017 and are expected to rise by another 1.2 degrees Celsius in the coming years. These trends have a major effect on public health, exacerbate urban heat islands in major cities like Tel Aviv and Jerusalem, and also have an effect on the rise in cooling-related electricity consumption and associated emissions.
Despite efforts to mitigate human exposure and vulnerability to heat stress, this phenomenon still requires further investigation. There are characteristics within cities, such as a lack of shading, that amplify pedestrian exposure to thermally stressful conditions. Many cities are not adapted to climate change, and there are vulnerable populations with different sensitivities to heat, such as disadvantaged populations living without air conditioning, individuals with pre-existing health conditions, and populations with different cultural living practices (e.g., Bedouins). Therefore, there is a strong motivation to assess and map the risks, identify vulnerable populations across the Negev, and provide policymakers with appropriate treatment strategies.
In response to these challenges, the ongoing research presented here addresses the impact of heat waves on public health in Israel, particularly within hot-dry cities located in the Negev desert. We employ advanced geospatial analysis to examine the relationship between high heat stress and morbidity and mortality, drawing on two types of data. High-resolution surface temperature data retrieved from remote sensing satellites and other airborne sources are gathered to construct thermal heat maps, which we integrate with information on morbidity and mortality along with demographic data sourced from local authorities and health service providers.
The work includes several stages: mapping of urban heat zones, identifying vulnerable population, assessing health impacts by analysis of public health data in relation to heat waves and developing a model to evaluate the correlation between high heat stress and health. Our goal is to provide evidence-based recommendations for urban planning decision-makers to mitigate heat related health risks in the Negev. In this way the study will address the critical gap in our understanding of how rapidly increasing temperatures affect urban populations, and we expect it to play an important role in both designing effective health strategies and guiding climate-responsive urban planning.
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