In 2024, a Record Surge in Hot and Humid Days Recorded

Shanghai endured prolonged extreme heat and humidity in 2024

Reuters/Nicoco Chan

The planet faced an unprecedented number of perilous hot and humid days in 2024, as climate change heightened global humidity levels to new extremes.

The worldwide average of humid heat days exceeded the 1991-2020 baseline, reaching 35.6 days last year—a rise of over 9.5 days compared to the previous high recorded in 2023. Climate Report 2024 Status as published by the American Weather Society.

During hot and humid weather, cooling becomes challenging as moist air hinders the body’s ability to cool itself through sweating. This makes such conditions exceptionally hazardous for human health. Kate Willett, who contributed to the report at the UK Met Office, states, “Your body starts to really struggle to offload the heat, so it’s really dangerous.”

Meteorologists track “wet bulb temperature” to assess heat and humidity. This involves utilizing a wet cloth on a thermometer bulb to illustrate the cooling effect of evaporation. High humidity diminishes the evaporation’s cooling effect, causing wet bulb temperatures to approach those of dry air.

As global temperatures rise, the atmosphere can retain more moisture, leading to not only stronger rainfall and storms but also heightened humidity levels. Willett notes that 2024 is “exceptionally” humid and ranks just behind 2023 in moisture content.

Certain regions, including the Middle East, Southeast Asia, and East China, have experienced extreme temperatures of 31°C (88°F) over short periods, with wet bulb temperatures surpassing 84°F multiple times, as indicated in the report. At such levels, prolonged exposure is deemed extremely hazardous and potentially fatal to human health.

Historically, scientists have considered a wet bulb temperature of 35°C as the survival threshold, beyond which individuals cannot endure outdoor conditions for more than a few hours without dire consequences. However, recent research published in 2022 suggests that the actual limit may be significantly lower, around 31°C. “Over 30°C is where your body really struggles,” Willett explains.

Topics:

Source: www.newscientist.com

In 2024, We Experienced a Record High of Dangerous Hot and Humid Days.

SEI 262102987

Shanghai endured extreme heat and humidity for days in 2024

Reuters/Nicoco Chan

The Earth recorded an unprecedented number of hazardous hot and humid days in 2024, as climate change escalates global humidity to alarming levels.

The worldwide average of humid heat days on land surpassed the 1991-2020 average, reaching 35.6 days last year, an increase of over 9.5 days from the previous record in 2023. Climate Report 2024 Status published by the American Weather Society.

Under hot and humid conditions, it is challenging for individuals to cool down, as moist air diminishes the evaporative cooling impact of sweating. Such weather poses serious risks to human health. Kate Willett from the UK Met Office, who contributed to the report, states, “Your body starts to struggle to shed heat, making it very dangerous.”

Meteorologists measure heat and humidity using “wet bulb temperature.” This is typically done by wrapping a wet cloth around a thermometer bulb, demonstrating the cooling effect of evaporated water. The readings indicate temperatures lower than in a dry bulb, as high humidity limits the cooling effect of evaporation and brings the wet bulb temperature closer to that of dry air.

As the globe heats up, the atmosphere can retain more moisture, leading to increased heavy rainfall, storms, and higher humidity levels. Willett describes 2024 as “exceptionally” humid, second only to 2023 due to higher moisture levels.

Specific regions, including the Middle East, Southeast Asia, and East China, have reached 31°C (88°F) within a short time span, with wet bulb temperatures exceeding 84°F multiple times, according to the report. At these levels, extended exposure outdoors is deemed extremely perilous and potentially lethal.

Traditionally, scientists consider a wet bulb temperature of 35°C the threshold for human survival, as people cannot withstand outdoor conditions for more than a few hours before succumbing. However, research published in 2022 suggests that the actual limit may be lower, around 31°C. “Over 30°C, your body really struggles,” Willett explains.

Topics:

Source: www.newscientist.com

What is a Heat Dome? Understanding Hot and Humid Weather Conditions

Sweltering and humid conditions have impacted nearly the entire eastern U.S. this week, triggered by “heat domes” settling over various regions.

On Wednesday, a heat advisory impacted approximately 150 million individuals, with temperatures exceeding 95 degrees Fahrenheit spreading through the Ohio Valley and along the East Coast. The National Weather Service predicts that “extremely dangerous heat” will persist until Thursday.

But what exactly is a heat dome, and how does it contribute to extreme heat?

Heat domes form when a strong high-pressure system remains stationary over an area, trapping warm air underneath like a lid on a pot.

These thermal domes are typically influenced by the jet stream’s behavior. The jet stream is a fast-moving ribbon of air that flows from west to east in the Northern Hemisphere, impacting weather patterns.

The jet stream is powered by the temperature disparity between the chilly polar regions and warm southern air masses. As it travels around the globe, it can create ripples that form troughs and ridges, leading to unusual weather phenomena.

For instance, certain ripples can intensify cold snaps, while others can move and amplify heat, resulting in higher humidity levels.

Heat domes can persist for days or even weeks, contributing to prolonged heat waves that can be deadly. Heat-related illnesses and fatalities can impact individuals of all ages, but children, those with pre-existing health conditions, and older adults are especially vulnerable to sudden temperature spikes.

Research indicates that climate change is increasing the frequency, intensity, and duration of heat waves globally. The hottest years on record since 1850 have all occurred within the last decade, according to the National Oceanic and Atmospheric Administration.

Some respite is anticipated later this week across the Midwest and East Coast, although temperatures are expected to remain high in the days ahead.

Source: www.nbcnews.com

Warm and Humid Climate Creates Ideal Conditions for Pterosaurs to Soar 220 Million Years Ago

A recent study by paleontologists integrated data on the ancient climate of a specific region with fossil distribution information regarding Triassic eye pteraurauromorphs (pterosaurs + lagerpetids).

Foffa et al. Lagerpetids, alongside overall pterygoid morphospace, likely thrived in southwestern Pangaea (i.e. modern-day South America), indicating that pterosaurs may have originated at lower latitudes in the Northern Hemisphere. Image credit: James Kuether.

“Pterosaurs were the first vertebrates to evolve powered flight more than 60 million years ago—the oldest known birds,” stated Davide Foffa, a paleontologist from the University of Birmingham.

“Nevertheless, our comprehension of early pterosaur evolution is constrained by significant temporal and anatomical gaps separating these highly adapted flying reptiles from their closest terrestrial relatives.”

“The fossil records for pterosaurs and their related species remain incomplete, and fundamental aspects of early evolution, including timing, domains of existence, initial radiation, and the ecological context of paleontology, are not well understood compared to other contemporary groups such as dinosaurs.”

The researchers concentrated on the distribution of two closely related groups: Pterosaurs and Lagerpetids.

“Lagerpetids existed roughly 240 million years ago as a group of agile reptiles that lived in smaller land areas and among trees,” they noted.

“These small terrestrial reptiles are now recognized as the closest relatives to pterosaurs, and this study shows they endured a wider range of climatic conditions than their aerial counterparts, including the arid landscapes of ancient Pangaea.”

“This adaptability resulted in a broader distribution of this group.”

“Conversely, pterosaurs seemed to be restricted to humid environments found in limited regions of the ancient world, as evidenced by fossils discovered in modern-day Italy, Austria, and the southwestern United States.

During the late Triassic period, global climatic conditions began to change, with an increase in warm and humid environments outside the equatorial region.

This shift provided an opportunity for flying reptiles to expand across the globe, including present-day high-latitude areas such as Greenland and South America.

“While dinosaurs roamed the Earth, I find it fascinating to envision that these formidable reptiles ruled the skies during that era,” remarked Dr. Foffa.

“However, the origins of pterosaurs remain cloaked in mystery. Our research contributes new insights into this puzzle, proposing that early evolution among groups was likely influenced by shifting climates and environments during the Triassic.”

“Climate change significantly affects biodiversity, both today and throughout geological history,” stated Dr. Emma Dunn, a paleontologist at Friedrich Alexander Universitat Erlangen Nurnberg.

“Recent advancements in modeling techniques have enabled paleontologists to better understand how climate change has shaped the biodiversity of significant fossil groups like pterosaurs in just the past few years.”

“The combination of ecological models and fossil data is emphasized by Dr. Alessandro Chiarenza, paleontologist at University College London, who noted:

“Lagerpetids flourished as generalists, while pterosaurs, initially constrained to a humid tropical niche with possibly limited flight capabilities, occupied equatorial territories.”

“As the climate transformed and forest corridors emerged, their wings propelled them to every corner of the planet, ultimately allowing them to survive one of Earth’s greatest extinctions.”

“What started as a tale of lost fossils is evolving into a paradigmatic example of how paleoclimate, past climate, and evolutionary innovations intertwine, illuminating the complex history that has fascinated paleontologists for over two centuries.”

Study published in the journal Natural Ecology and Evolution.

____

D. Foffa et al. Paleobiogeography of climate drivers and lagerpetids and early pterosaurs. Nat Ecol Evol published online on June 18th, 2025. doi:10.1038/s41559-025-02767-8

Source: www.sci.news