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The Sixth Mass Extinction | Earth Wise

February 16, 2022 By EarthWise Leave a Comment

Extinction is a natural part of life. Plants and animals disappear all the time. When one species goes extinct, its place in the ecosystem is typically filled by another. The so-called normal rate of extinction is thought to be somewhere between 0.1 and 1 species per 10,000 species per 100 years.

A mass extinction event is when species disappear at a much faster clip than they can be replaced. By definition, mass extinction is when about three-quarters of the world’s species are lost in a short amount of time on a geologic scale, which is measured in millions of years.

There have been five previous mass extinction events throughout the history of life on earth. Today, many experts warn that a sixth mass extinction event is already underway – the first since dinosaurs were wiped out some 65 million years ago. While previous mass extinctions were the result of extreme natural phenomena like volcanic eruptions and asteroid strikes, this one is a result of human activities.

Researchers from the University of Hawai’i at Manoa and the National Museum of Natural History in France recently published a comprehensive assessment of evidence of this ongoing extinction event. The researchers estimated that since the year 1500, Earth could already have lost between 7.5% and 13% of the two million known species on Earth. This amounts to a staggering 150,000 to 260,000 species.

While mitigating the effects of climate change and reducing the rates of habitat loss would help, raising awareness of this crisis and its fallout for all life forms – including us – would be most effective in driving change.

The time we have to avoid dramatic consequences is rapidly running out.

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Strong evidence shows Sixth Mass Extinction of global biodiversity in progress

Photo, posted September 18, 2015, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The New Normal Weather

March 13, 2019 By EarthWise Leave a Comment

We often hear about how the weather is getting stranger all the time, but do most of us really think so? What kinds of weather do we really find remarkable and has that been changing?

A study led by the University of California, Davis used some very modern tools to examine the question of what people might consider to be “normal” weather. To reach their conclusions, they quantified the timeless pastime of talking about the weather by analyzing Twitter posts. They sampled over 2 billion geolocated tweets to determine what kind of events generated the most posts about the weather.

Unsurprisingly, they found that people most often tweet when temperatures are unusual for a particular place and time of year. However, if the same weather persisted year after year, it generated less comment on Twitter, indicating that people began to view it as normal in a relatively short amount of time.

The study indicates that people have short memories when it comes to what they consider normal weather. On average, most people base their idea of normal weather on what has happened in just the past two up to maybe eight years. This disconnect with the historical climate record may obscure the public’s perception of climate change.

After repeat exposures to historically-extreme temperatures, people talk less about the weather, even though particularly hot or cold weather conditions make them unhappy and grumpy. Even though we are experiencing conditions that are historically extreme, we might not consider them to be particularly unusual if we tend to forget what happened more than a few years ago. Things may be getting worse, but they apparently are just the new normal.

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Tweets tell scientists how quickly we normalize unusual weather

Photo, posted March 11, 2013, courtesy of Adedotun Ajibade via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cold Weather In A Warming Climate

June 25, 2018 By EarthWise Leave a Comment

The climate is warming. The average global temperature is going up year after year, bringing about significant changes to weather around the world. But the fact is that these changes don’t always lead to warmer weather. And ordinary variations in local weather can also go in either direction.