On October 10, 2024, as part of the SDG Local Solutions series, the United Nations Development Program (UNDP) hosted a webinar to discuss how cities are addressing the increasing threat of extreme heat. The session focused on two local governments—Miami-Dade County in the United States and the city of Seville in Spain—showcasing local solutions to protect vulnerable communities and adapt to the escalating impacts of rising temperatures.
As global temperatures rise, cities grapple with increasingly intense and frequent heat waves. Miami and Seville stand out as two cities implementing proactive strategies to mitigate the effects of extreme heat and safeguard their communities. By examining their unique challenges, innovative solutions, and ongoing obstacles, we can draw valuable lessons for urban centers worldwide striving to combat this pressing climate crisis.
The video recording can be watched on our YouTube channel – also available in Spanish and French.
Miami: tackling extreme heat in a humid urban environment
Miami Dade County has become a focal point for climate challenges because of rising sea levels, hurricanes, and the relentless escalation of extreme heat. In recent decades, the city has seen a dramatic increase in days with temperatures exceeding 32.2°C (90°F), now averaging 77 days annually—an increase of nearly one °C over 50 years. The summer of 2023 brought over 60 days with heat indices surpassing 40.5°C (105°F).
The city’s unique geography and urban development patterns exacerbate the issue. High humidity intensifies the heat index, while urban heat islands—caused by extensive asphalt, concrete, and a lack of vegetation—make some neighborhoods up to 5°C warmer than others. Vulnerable populations, such as low-income communities and the 300,000 outdoor workers in Miami, bear the brunt of these conditions, experiencing elevated rates of heat-related illnesses, including heat exhaustion and stroke.
The solutions
To address these challenges, Miami implemented a comprehensive Extreme Heat Action Plan centered around three key goals:
- Informing and preparing residents: educational campaigns and training initiatives have equipped workers, volunteers, healthcare providers, and community leaders to identify and respond to heat-related illnesses. Public messaging on hydration, rest breaks, and seeking shade targets at-risk populations, including the homeless and outdoor laborers.
- Expanding access to cooling resources: Miami installed 1,700 high-efficiency air conditioning units in public housing and increased funding for weatherization in low-income homes. The county also mandated that all new public buildings, including affordable housing projects, feature cool roofs and be solar-ready.
- Mitigating urban heat islands: Miami doubled its annual tree-planting efforts, reaching 16,000 trees annually, prioritizing neighborhoods with low tree canopy coverage and high poverty rates. Additionally, shaded bus stops and pedestrian-friendly transit corridors were developed to ensure thermal comfort and safety for commuters.
The challenges
Despite these efforts, significant hurdles remain. A significant challenge for Miami is how to reach people and ensure that they adopt the recommended practices to protect themselves from extreme heat. The city’s diverse population requires tailored outreach strategies that consider cultural and linguistic barriers. Partnering with community-based organizations has proven essential to connecting with vulnerable groups, such as undocumented residents and non-English speakers. Furthermore, funding limitations constrain the pace and scope of these initiatives while climate change continues to amplify the frequency and intensity of extreme heat events.
Seville: blending tradition and innovation to combat extreme heat
Seville, situated in the heart of Andalusia, faces scorching summers with temperatures regularly exceeding 38°C. In recent years, record highs of up to 51°C have been observed during heat waves. Unlike Miami, Seville’s challenges are compounded by its reliance on tourism, a sector vulnerable to disruptions caused by extreme heat.
The urban layout and limited cooling infrastructure in public spaces further exacerbate the issue. Seville’s historical architecture offers some resilience to interior heat, but outdoor environments remain perilous, particularly in heavily trafficked areas like plazas and transportation hubs.
The solutions
Seville has embraced modern innovation and cultural practices to address extreme heat. Key initiatives include:
- Watercool project: this initiative utilizes water recirculation to cool urban spaces. A pedestrianized street spanning nearly one kilometer was equipped with shaded seating, climatized bus stops, and a plaza designed to reduce temperatures by up to 5°C. Though seemingly modest, this reduction significantly improves comfort when temperatures soar above 45°C.
- Cartuja Qanat project: inspired by ancient techniques, this initiative focuses on cooling open-air spaces using water and natural ventilation. The refurbished area includes shaded amphitheaters for cultural events, creating comfortable spaces for community gatherings even during peak summer months.
- Urban planning for shade: recognizing the importance of green and gray shade solutions, Seville has prioritized tree planting and the installation of shading structures across the city. These measures have been shown to lower surface temperatures by up to 12°C, dramatically improving outdoor thermal comfort.
- Cultural adaptation: the city actively promotes traditional practices like siestas and adjusts activity schedules to reduce exposure during peak heat hours. Tourism agencies and hotels educate visitors on heat safety, including hydration tips, light clothing recommendations, and hand fans—iconic in Seville’s culture and surprisingly effective at cooling.
The challenges
Seville faces substantial financial constraints, as municipal budgets are insufficient to scale these projects to meet growing demands. Regulatory hurdles further complicate the implementation of comprehensive urban planning measures. Additionally, as a significant tourist destination, Seville must balance climate adaptation efforts with the need to sustain its economy, particularly during the high summer season.
Lessons learned
Miami Dade County and Seville illustrate two distinct approaches to addressing extreme heat, shaped by their unique climates, cultures, and resources. Miami’s plan emphasizes technological solutions, equitable access to cooling, and community engagement, while Seville combines historical knowledge with innovative urban planning and cultural resilience.
Key takeaways for other cities:
- Develop comprehensive heat action plans: address immediate cooling needs and long-term urban heat mitigation strategies.
- Collaborate across sectors: engage public, private, and civil society stakeholders to maximize impact and reach.
- Prioritize shade and vegetation: invest in green and gray shading solutions to cool outdoor environments effectively.
- Educate and empower communities: equip residents with the knowledge and tools to protect themselves during heat waves.
- Leverage local traditions: adapt solutions to each city’s cultural and historical context to ensure community buy-in and relevance.
Extreme heat is an escalating global challenge, but with strategic planning, innovation, and collaboration, cities can transform into hubs of climate resilience, offering valuable lessons for others navigating the same threats.
