This work highlights an urgent reality: we're not just approaching dangerous heat thresholds - we've already crossed them in many places.
Paper under review ER:H.
Come discuss at AGU or reach out!
📍 Mon Dec 15, 4:16pm, Room 298-299, New Orleans Convention Center
5/5

These limitations have increased significantly over the past 75 years, with notable spikes during El Niño years and in 2024.
Without stronger climate action and adaptation measures, livability constraints will only expand, especially as global populations age and become more vulnerable to heat.
4/5

For younger adults: we find hundreds of hours/year of restrictions on light activity in South & Southwest Asia's hottest regions.
For older adults: we find thousands of hours/year in tropical Asia and Sub-Saharan Africa. That's up to 1/3-1/2 of the year when even light activity is dangerous.
3/5

Using 75 years of global, hourly ERA5-Land data (1950-2024) and the HEAT-Lim model, we mapped where heat already limits safe physical activity for younger adults (18-40) and older adults (65+).
The results are stark, especially for older adults, where the hottest hours already limit livability.
2/5

10/ 🌴 Read the full review in One Earth to learn more about actionable solutions and research priorities for supporting tropical outdoor workers in a warming world. Let's work together for a more resilient future. 🔗 doi.org/10.1016/j.on... (10/10)

9/ 🚀 The path forward: Immediate adaptation is critical, but the ultimate solution lies in cutting emissions and preserving tropical forests or other low-cost cooling strategies. Without action, the safety and livelihoods of millions remain at risk. (9/10)

8/ 🧪 Research gaps remain: How do we adapt to compounded stressors like heat + air pollution? What are the unintended consequences of adaptation efforts? Addressing these will refine our strategies for building resilience. (8/10)

7/ 🌟 Governments, employers, and communities each have roles:

Enact labor protections
Promote education on heat risks
Provide adaptive tools like flexible work hours, lightweight clothing, and cooling tech
Develop sustainable livelihoods (7/10)

6/ 💡 To protect workers, we need layered solutions:

🌳 Primary: Reduce heat exposure (emissions cuts, reforestation, and urban greening)
⏳ Secondary: Mitigate risks during heat events (e.g., rest breaks, cooling stations).
🏥 Tertiary: Provide recovery support (medical care and financial aid). (6/10)

5/ 🚶‍♀️ Individual workers are adapting—changing work hours, hydrating, or seeking shade—but these solutions have limits. Chronic heat exposure leads to long-term health issues like kidney disease and heat stroke, reducing resilience over time. (5/10)

4/ 🏞️ Land-use changes exacerbate increasing heat exposure from global warming. Deforestation can remove natural cooling (shade, ET), urbanization worsens heat islands, and irrigation can increase humid heat stress. (4/10)

3/ 🌍 The toll isn't just physical—it's economic. Heat stress costs outdoor industries hundreds of billions of $USD annually if we estimate lost potential productivity. This burden falls hardest on those in agriculture, construction, and informal sectors, especially in low-income nations. (3/10)

2/ 💼 Today, about 20% of annual work hours in the tropics already exceed safe thresholds (ISO) for continuous heavy labor (acclimatized workers, ~415W intensity). At ~2°C global warming, this rises to 28%. By mid-century, nearly 800M workers may lose half their safe working hours annually. (2/10)

📚 For more details, read our paper: DOI: 10.1029/2024JD041150. Let’s discuss the implications for your region or field! 🌎 #ClimateResearch #PaleoScience
7/

🚩 Takeaway: Understanding the range of "natural" variability is critical for predicting how climate patterns will interact with warming—and for better water management in vulnerable regions. 💧 #Hydroclimate
6/

🌡️ Despite these challenges, DA reconstructions reveal changes in relationships between oceans and large-scale hydroclimate patterns that models alone often miss, offering crucial insights into natural variability before the industrial era.
5/

🧩 Caveats: We need more data, especially in the oceans! Proxy data availability (particularly in the early record) and model assumptions can introduce uncertainties. For example, reconstruction methods assume stable relationships between climate modes and proxies, which may oversimplify reality.
4/

🌊 Using DA (combining climate models + past paleoclimate data, like information from tree rings & corals), we reconstructed rainfall-SST relationships. We found shifts on decadal to centennial timescales in the southwestern U.S. and Lower Mississippi River Basin. 📜
3/