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Record-breaking tropical heat and humidity predicted this summer

The tropical belt braces for unprecedented heat this summer, with conditions ripe for new records in temperature and humidity. This forecast, based on new research from the University of California, Berkeley, underscores the escalating impact of climate change coupled with an intense El Niño.

Why humidity makes heat dangerous

Our bodies rely heavily on sweating to stay cool. When sweat evaporates from our skin, it carries heat away with it, lowering our internal temperature. However, in high humidity, the air is already heavily laden with water vapor.

This makes it much harder for our sweat to evaporate, reducing its cooling effect. Essentially, high humidity prevents our natural temperature regulation process from working efficiently, making it much more difficult for our bodies to stay cool in hot conditions.

“If you can’t cool your body to below 98.6°F, or 37°C, then you’ll die,” said study co-author Professor William Boos. “Sweat is the main way we have to cool ourselves when it gets hot. So if sweating will not allow you to cool below your core body temperature, that’s the survivability limit,” explained William Boos, a UC Berkeley professor of earth and planetary science.

El Niño and global warming lead to tropical humidity

The ongoing rise in Earth’s average temperature, known as global warming, is increasing the amount of water vapor in the atmosphere. This is because warmer air can hold more moisture.

El Niño, a natural weather pattern that causes warming in the tropical Pacific Ocean, adds even more heat to the system. This further boosts evaporation, sending large amounts of warm, moist air into the upper atmosphere.

Eventually, some of this moisture descends back to the surface, creating those hot, muggy conditions along with intense thunderstorms that don’t always bring lasting relief from the heat.

“When El Niño happens,” Boos explains, “the upper atmosphere gets warmer, which means that these downdrafts won’t be as cold. So your surface overall will move to a higher heat and humidity content.”

Predicting tropical heat and humidity

Scientists at UC Berkeley developed a powerful tool to predict this summer’s heat and humidity patterns. They combined statistical analysis with extensive historical climate data, spanning 45 years, and factored in the effects of both El Niño and ongoing global warming.

The analysis allowed the experts to isolate specific patterns where El Niño’s temporary warming amplifies the longer-term warming trend caused by climate change. The result is a chilling prediction related to tropical heat and humidity: the tropics have a 7 in 10 chance of experiencing record-breaking heat and humidity levels.

It’s important to note that this method doesn’t pinpoint the exact weather on any given day. Instead, it reveals a large-scale trend for the tropical heat and humidity. This type of prediction is incredibly valuable because it gives governments, health organizations, and communities in these regions precious time to prepare and implement strategies to protect people, livestock, and crops from the dangerous effects of extreme heat and humidity.

Location of tropical heat and humidity

Unfortunately, the tropical heat and humidity won’t be evenly distributed. India, large swaths of Africa, Central and South America, Australia, and even Florida and Texas are most at risk.

“I think it provides a pretty good bar for the supercomputer models that are predicting climate on a seasonal time scale,” said Boos. Some areas, like northern India, face a 50 percent chance of suffering record levels of extreme heat this summer.

This isn’t a forecast to ignore. Organizations, from governments to humanitarian aid groups, can use this prediction to plan for increased medical needs and resources.

Preparation for tropical heat and humidity

Preparing for tropical heat and humidity can significantly reduce the risk of heat-related illnesses and improve comfort. Here are some tips:

Stay informed

  • Weather apps and alerts: Regularly check local weather forecasts and set up alerts for heat advisories on your smartphone or other devices.
  • Local news: Follow local news for updates on weather conditions and safety advisories.

Adjust daily routines

  • Avoid peak heat: Limit outdoor activities to early morning or late evening when temperatures are cooler.
  • Dress appropriately: Wear lightweight, loose-fitting, and light-colored clothing to reflect sunlight and help maintain body temperature.

Optimize living spaces

  • Cooling systems: Ensure air conditioning systems are well-maintained before the onset od predicted tropical heat and humidity. Consider installing energy-efficient window films or blackout curtains to reduce heat absorption.
  • Fans and ventilation: Use fans to circulate air. Open windows during cooler periods if it is safe to do so and secure against insects.
  • Insulation: Improve home insulation to keep the heat out and the cool in.

Hydration and diet

  • Water intake: Increase your water intake to stay hydrated. Avoid alcohol and caffeine, as they can lead to dehydration.
  • Cool foods: Eat smaller meals more frequently. Include fruits and vegetables that are high in water content, such as cucumbers, oranges, and watermelons.

Health management

  • Recognize heat exhaustion signs: Know the signs of heat exhaustion, which include heavy sweating, weakness, cold, pale, and clammy skin, nausea or vomiting, and fainting.
  • Emergency kit: Keep a well-stocked first aid kit that includes items like water, electrolytes, and basic medical supplies.

Community and vulnerable groups

  • Check on others: Regularly check on elderly family members, neighbors, and others who may not have air conditioning or who spend much of their time alone.
  • Community cooling centers: Utilize public spaces that are air-conditioned, like libraries or community centers, which may serve as cooling centers during heat waves.

Preparation for power outages

  • Emergency plans: Have a plan in place for potential power outages. This includes having battery-powered fans, extra batteries, and portable chargers for devices.
  • Backup power: Consider investing in a generator or solar-powered chargers for essential devices.

Pet safety

  • Pet care: Ensure pets have adequate shade and water. Never leave pets in a closed vehicle, as tropical heat and humidity can rise to dangerous levels rapidly.
  • Walking hours: Walk pets during cooler parts of the day to prevent overheating and burns from hot pavements.

Preparation is key, especially in regions where extreme heat is not just uncomfortable but potentially dangerous.

The study is published in Geophysical Research Letters.


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