The intensifying UHI effects, combined with El Niño, pose severe health risks, particularly for vulnerable groups such as the elderly, children, and those with pre-existing health conditions. Prolonged exposure to extreme heat can lead to dehydration, heatstroke, and cardiovascular issues. Cities with limited resources, like Lagos, experience more severe UHI effects compared to wealthier cities like Singapore, where mitigation strategies are more advanced. The economic disparity in addressing these challenges raises concerns about environmental justice, as poorer populations bear the brunt of the impacts despite contributing less to global warming.