debate

Plants Make Sounds | Earth Wise

May 9, 2023 By EarthWise Leave a Comment

Some people talk to their plants. It is highly unlikely that the plants are listening, but recent research has found that plants are doing quite a bit of talking of their own.

It turns out that plant emit a variety of click-like sounds, especially when they are stressed in some way, such as being dehydrated or injured. The sounds are actually fairly loud – comparable to the volume of human speech – but occur at frequencies well above the range of human hearing.

The study at Tel Aviv University in Israel monitored plants in a greenhouse that were subjected to various stresses over time. Unstressed plants emitted less than one sound per hour, on average, while stressed plants emitted dozens of sounds every hour.

Recordings of the plant sounds were analyzed by specially developed artificial intelligence algorithms. The algorithms learned how to distinguish between different plants and different types of sounds. Eventually, they could identify the plant and determine the type and level of stress from the recordings. They could even do this in a greenhouse with a great deal of background noise.

The study resolved a very old scientific controversy about whether plants emit sounds. Not only do they, but the sounds contain useful information. We don’t yet know what the mechanism is for plant sounds. It is likely that in nature, the sounds are detected by various animals and perhaps even plants that can detect the high frequencies. And perhaps they react to them as part of seeking food, shelter, or other services that plants provide. Given the right tools, we humans may also be able to make use of the sounds being made by plants.

**********

Web Links

Plants Emit Sounds – Especially When Stressed

Photo, posted February 20, 2009, courtesy of ProBuild Garden Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Falling Lithium Prices | Earth Wise

May 1, 2023 By EarthWise Leave a Comment

Lithium, the key element in the batteries that power electric cars, as well as smartphones, tablets, and laptop computers, is sometimes called white gold. Over time, the price of the metal has gone up and up. But recently, and surprisingly, the price of lithium has actually gone down, helping to make electric vehicles more affordable.

Over the first couple of months of this year, the price of lithium has dropped by nearly 20%. The price of cobalt, another important component of vehicle batteries, has fallen by more than half. Even copper, another battery material, has seen its price drop by 18%.

Many analysts predicted that prices of these commodities would stay high or even climb higher. The reason for the decline, as well as whether it is likely to persist, is the subject of much debate.

Some experts believe that the price drops are a result of demand not being as high as expected, perhaps related to slowing sales growth of EVs in Europe and China after certain subsidies expired. Other industry experts said that the drop was a result of new mines and processing plants providing additional supply sooner than was thought possible.

Despite the price drops, mining and processing lithium remains an extraordinarily profitable business. It costs from $5,000 to $8,000 to produce a ton of lithium that sells for ten times that amount. With such fat profit margins, there is no shortage of banks and investors eager to finance lithium mining and processing projects. Such profit margins are probably not sustainable and that will likely result in more reasonable prices over time.

There is plenty of lithium in the world. The huge demand for it is a recent phenomenon and the world is still working out how to meet that demand.

**********

Web Links

Falling Lithium Prices Are Making Electric Cars More Affordable

Photo, posted January 9, 2023, courtesy of Phillip Pessar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

What Does Conservation Really Mean? | Earth Wise

June 2, 2021 By EarthWise Leave a Comment

There is a great deal of interest in protecting nature and, in many cases, restoring aspects of nature that have been lost. But what do these things really mean?

What is most important? Protecting iconic species? Strengthening nature’s resilience? Several recent scientific papers address these questions and come up with rather different answers.

It isn’t even clear what constitutes a pristine ecosystem. According to some experts, ecosystems that have lost most of their large mammal species, for example, cannot be considered intact. By that standard, only a tiny fraction of the world’s ecosystems remains intact.

Other experts contend that preserving individual species is not what really matters. Studies have shown that many ecosystems have undergone and continue to undergo massive species shifts over time with frequent extinctions along the way. Nevertheless, the ecosystems continue to flourish with new species replacing others to perform the various functions required.

Some perspectives consider intact ecosystems to be those devoid of human influence. But that notion is not universally held. There is the idea that most of the world’s ecosystems were essentially untouched until perhaps 500 years ago when European exploration expanded greatly. But the reality is that even 12,000 years ago, nearly three-quarters of terrestrial nature was inhabited, used, and shaped by people. However, those human interactions were similar to how many indigenous and local peoples across the globe still live, not like the interactions of modern civilization that result in massive changes to ecosystems.

**********

Web Links

Species or Ecosystems: How Best to Restore the Natural World?

Photo, posted November 21, 2003, courtesy of Megan Coughlin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Which Cities To Save From The Changing Climate

October 28, 2019 By EarthWise Leave a Comment

After several years of brutal flooding and hurricanes in the U.S., a distressing debate is emerging: if there is not enough money available to protect every coastal community from the effects of global warming, how do we decide which ones to save first.

Recent research looked at the costs involved in providing basic storm-surge protection in the form of sea walls for all coastal cities with more than 25,000 residents. That number was $42 billion. Expanding the list to include communities smaller than 25,000 people would increase that cost to more than $400 billion. Realistically, that is just not going to happen.

This particular study only looked at sea walls and no other methods for minimizing flood risk, such as moving homes and businesses away from the most flood-prone areas. It also didn’t look at additional and costlier actions that will be required even with sea walls, such as revamping sewers, storm water, and drinking water infrastructure.

The facts are that many cities, especially small ones, will not be able to meet the costs facing them. Those that can’t will depend on federal funding. But even optimistically large proposals for federal infrastructure spending are likely to fall far short of the vast need. Ultimately, the money will end up being spent where it can do the most good – even if it means that some places are left out.

But what criteria will be used to direct the money? Economic value? Historic significance? Population? Political influence?

This is a looming and massive issue whose chief obstacle may be that many officials refuse to acknowledge that it is happening. This is the next wave of climate denial – denying the costs that we are all facing.

**********