altitudes

As global temperatures continue to rise and ecosystems shift, animals are left with limited options. They must either adjust to the changing conditions in their habitats or relocate to cooler environments. For many species, neither choice is easy – or sometimes even possible.

Ecologists had long assumed birds were among the most adaptable species in a warming world simply because they can fly to higher altitudes or towards global poles. But a new study by researchers from Yale University found that even birds are struggling to stay ahead of rising global temperatures.

The study, which was recently published in the journal Nature Ecology and Evolution, analyzed 20 years of data from 406 bird species across North America. They found that while most birds did shift their ranges northward – by about 40 to 50 miles on average during the summer – the changes weren’t enough to keep up with the rapid pace of climate change.

Birds still experienced significant warming in their new areas when compared with temperatures in their original home range. In fact, warming was about 1.35 degrees Celsius more in summer, and a striking 3.7 degrees more in winter. And some species, especially those with limited flight ranges or specific habitat needs, like the cactus wren, didn’t move at all.

Highly mobile birds like the blue-winged warbler did better, avoiding nearly two degrees of warming by traveling more than 100 miles north. But even they couldn’t completely dodge the heat.

The findings raise serious concerns about whether less mobile species can survive in a warming world, and underscores the urgent need to better understand and manage those most vulnerable to climate-driven extinction.

**********

Web Links

Even birds can’t outfly climate change

Photo, posted March 1, 2023, courtesy of Henry via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A vast cloud of dust from the Sahara Desert blanketed the Caribbean in late June before drifting across the southeastern U.S. The phenomenon is nothing new; only the magnitude of the occurrence this time around was unusual. According to experts, this is the most significant Sahara dust event in 50 years.

The Sahara Desert is the major source on Earth of mineral dust, with some 60-200 million tons of it per year being lifted into the atmosphere. Convection currents over hot desert areas lift the dust to very high altitudes. From there, it can be transported worldwide by winds. The dust, combined with the extremely hot, dry air of the Sahara Desert often forms an atmospheric layer called the Saharan Air Layer, which can have significant effects on tropical weather by interfering with the development of hurricanes. The Saharan Air Layer typically moves across the North Atlantic every three to five days from late spring to early fall, peaking in the middle of the summer. It can occupy a layer as much as two miles thick in the atmosphere.

The dust plume this summer was highly visible from space, covering thousands of miles of the Atlantic Ocean and the Caribbean Sea.

A common effect of Sahara dust is that normally blue skies can acquire a milky haze, but beyond that can lead to spectacular sunsets. But apart from the visual spectacle, the dust can aggravate the conditions of people with asthma, respiratory illnesses, and allergies. On the positive side, as long as the dust is around, it is much less likely that tropical storms and hurricanes will form.

**********

Web Links

Sahara dust blankets Caribbean, air quality hazardous

Photo, posted June 22, 2020, courtesy of Sagar Rana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.