key takeaways from the report
1. Boston is already experiencing the effects of climate change.
In Massachusetts, we have already seen average temperatures increase by almost 3.5°F. Over the last decade, Boston experienced more hot days and nights than any decade in the previous 50 years.
2. We will experience increasingly hotter summers and greater heat stress.
Even if major action is taken to reduce emissions, the number of days in Boston over 90°F will increase from a historical average of 10 days per year to as many as 46 days per year by the 2070’s.
3. Preparing for hotter summers is critical to public health and safety.
In the United States, extreme heat is already the #1 cause of weather-related deaths, more than tornadoes, hurricanes, flooding, and cold weather combined.
4. We must continue to prepare for both the near-term and long-term.
The Heat Plan provides a citywide framework to build a more just, equitable, and resilient Boston, both today and in the coming decades.
5. The entire city of Boston is a heat island.
Cities like Boston have densely developed buildings, asphalt, pavement, dark roofs, and other heat sinks that store and release heat on a hot day, resulting in average temperatures that are higher than surrounding communities.
6. Not everyone experiences a hot day in Boston in the same way.
Some areas of Boston are hotter than the rest of the city, entering high-heat conditions sooner, reaching higher air temperatures, and remaining in heat wave conditions longer.
7. Equitable heat resilience means putting people at the center.
We can deliver more just and equitable outcomes for residents by also increasing access to cooling resources and addressing underlying factors that result in greater burdens upon some residents.
8. How we build climate resilience matters.
By centering people and personal experiences alongside policies focused on infrastructure and buildings, we can deliver a wider range of strategies that can better address individual and systemic injustice and inequity.
9. Preparing for hotter summers provides multiple benefits.
Investments in heat resilience can provide multiple benefits, including lower greenhouse gas emissions, less air pollution, healthier residents, safer commutes and workplaces, and greater quality of life.
10. Together, we can build a more just, equitable, and resilient Boston.
By implementing the strategies in Boston’s Heat Plan, we can help put Boston on a path to becoming a Green New Deal city and ensure that everyone can thrive in the face of climate change.
What does heat resilience mean in Boston?
Ensuring that all residents have the resources needed to stay safe and cool during hot summers.
Reducing temperatures in hotspots areas throughout the city through targeted investments.
Indoor & outdoor approach
Transforming indoor and outdoor spaces to help preserve the health and wellbeing of residents.
BOSTON'S STRATEGIES ADDRESS ALL FACTORS OF HEAT RISK:
Low adaptive capacity can result from barriers to opportunities and resources that help cope with heat stress. People with lower adaptive capacity may be unable to make their immediate surroundings cooler or more comfortable, to relocate to a cooler place, or to receive help from others nearby.
- Individuals who live alone or do not have close social contacts to reach out to for support
- Homebound individuals or people with limited mobility
- People without A/C or limited use due to utilities affordability
- People lacking access to transportation
- Individuals facing language barriers
INTRODUCTION TO HEAT VULNERABILITY
HEAT IMPACTS ON REDLINED NEIGHBORHOODS
Historic and future heat trends
HISTORIC HEAT TRENDS
In Massachusetts, due to climate change, temperatures have increased by 3.5°F since the beginning of the 20th century. In the last decade (2010–2020), Boston experienced more hot days than any decade in the previous 50 years. Historically, Boston summers included around 10 days over 90°F.
FUTURE HEAT TRENDS
How much Boston’s temperatures continue to increase will depend on how quickly and by how much global greenhouse gas emissions can be reduced. Even a small increase in average temperatures will lead to more frequent very hot days and nights, along with longer and hotter heat waves.
CITYWIDE HEAT ANALYSIS
Data from a very intense heat wave from July 2019 with peak temperatures of approximately 96.8°F was used to produce modeled air temperature maps for the plan. These maps below include daytime temperature, nighttime temperature, heat event duration, and urban heat island index.
The daytime air temperature maps represented here show temperatures across Boston at 3pm during the modeled heat wave. Daytime temperatures are higher in areas that have high solar exposure, limited vegetation, or limited ventilation.
The nighttime air temperature map shows temperatures across Boston at 3am during the modeled heat wave. Nighttime temperatures are higher in densely built urban centers that have limited ventilation, restricted sky view, and high thermal storage.
URBAN HEAT ISLAND INDEX
The Urban Heat Island Index (UHII) map shows the difference in temperatures across Boston during the modeled heat wave in comparison to the coolest points in Boston. The UHII is higher in areas with wide roads, limited vegetation, and dense development.
The heat duration maps show the number of hours exceeding 95°F during the day or 75°F at night for areas across Boston during the modeled heat wave. Areas like Chinatown remain in high-heat conditions for 37 hours, with afternoon air temperatures climbing to 104 to 107°F and nighttime temperatures in much of the neighborhood over 90°F.
BOSTON HEAT EXPERIENCES
HEAT RESILIENCE STORies
The Heat Resilience Story Comic Builder is a web-based community engagement tool developed for the plan to cultivate empathy through storytelling. Using the Comic Builder, participants can build a personal avatar and design three scenes that reflect their heat experience. Heat stories were compiled into a virtual flip book for participants to read each other’s stories and see the variety of heat experiences.
CITYWIDE HEAT RESILIENCE STRATEGIES
REDUCE HEAT EXPOSURE
Reduce indoor and outdoor urban heat exposure, intensity, and duration by enhancing the capacity of the built environment to recover from daytime heat.
ADAPT TO HEAT
Expand choices for staying cool during heat waves and improve awareness of actions residents can take to stay safe and cool.
REDUCE SENSITIVITY AND FOSTER HEALTHY, CONNECTED COMMUNITIES
Create healthier, more connected neighborhoods that help reduce underlying social determinants of health that increase heat risk.
PRIORITIZE MULTIPLE BENEFITS
Leverage heat resilience strategies to advance economic opportunity, reduce carbon emissions, increase green spaces, and improve health for Bostonians and our environment.
AN ENVIRONMENTAL JUSTICE AND EQUITY LENS
By centering environmental justice and equity, Boston can better address root causes of increased risk and vulnerability in communities who are disproportionately affected by climate change - and ensure that the City of Boston equitably protects all residents and effectively addresses the needs of the most overburdened residents.
Continue to refine temperature models and utilize them alongside robust community engagement to help inform decisions.