Quantcast
Environmental News for a Healthier Planet and Life

Help Support EcoWatch

Video Shows Relationship between Damming Rivers and Climate Change

Climate
Video Shows Relationship between Damming Rivers and Climate Change

International Rivers

International Rivers and Friends of the Earth International have teamed up to create a state-of-the-art Google Earth 3-D tour and video narrated by Nigerian activist Nnimmo Bassey, winner of the prestigious Right Livelihood Award. The production was launched on the first day of the COP17 climate meeting in Durban, South Africa. The video and tour allow viewers to explore why dams are not the right answer to climate change by learning about topics such as reservoir emissions, dam safety and adaptation while visiting real case studies in Africa, the Himalayas and the Amazon.

The Durban climate meeting is themed "saving tomorrow today." Yet a global dam boom being promoted by dam proponents—including dozens of megadams proposed for Africa’s major rivers—could make a mockery of this vision. "Healthy rivers are becoming an endangered species because of the impacts of large dams," said Jason Rainey, executive director of International Rivers. "There is no ‘tomorrow’ without rivers—we can’t adapt to a changing climate without them."

"Many African nations are dangerously dependent on hydropower, yet new dams are being built without any analysis of how climate change could affect their economic viability or their safety," said Nnimmo Bassey, chair of Friends of the Earth International and narrator of the Google Earth video. "Africa cannot afford dried-up reservoirs or dam collapses on top of the already high costs of adapting to a changing climate. We must develop climate-safe energy systems that improve lives, share the development wealth and help us all weather the coming storm."

Watch the video below and take action to protect rivers from climate change and dams:

Download the Google Earth Tour by clicking here.

Using state of the art animation, the Google Earth production illustrates three key reasons that large dams are the wrong response to climate change:

  • River flows are increasingly unpredictable. Large dams have always been based on the assumption that future stream-flow patterns will mirror those of the past, but this is no longer true. Climate change has begun to significantly and unpredictably change precipitation patterns. More frequent droughts will make many hydropower projects uneconomic. More extreme rainfall will increase the risk of dam failures and catastrophic flood releases.

  • Healthy rivers are critical for supporting life on Earth. Big dams make it harder for people and ecosystems downstream of dams to adapt to climate change by reducing water quality and quantity, drying up forests and wetlands, flooding productive land and destroying fisheries.

  • Dam reservoirs emit greenhouse gases, especially in the tropics. Dam reservoirs are a globally significant source of one of the most potent gases, methane. Meanwhile, free-flowing rivers play a crucial role in helping trap carbon.

The tour illustrates how melting glaciers in the Himalayas—an effect of climate change—may lead to higher flood and safety risks for communities living downstream of dams. The tour plunges the viewer deep inside one of Brazil's dirtiest reservoirs, at the Tucuruí Dam, to visualize how rotting organic material creates methane gas, which bubbles up from dam reservoirs to emit greenhouse gases. The tour visualizes what smaller, decentralized projects would look like—an approach that could more efficiently meet energy and water needs in Africa, while also reducing the economic risks of drought-crippled dams and protecting life-giving rivers.

More information:

For more information, click here.

Sustainable t-shirts by Allbirds are made from a new, low-carbon material that uses a mineral extract from discarded snow crab shells. Jerry Buttles / Allbirds

In the age of consumption, sustainability innovations can help shift cultural habits and protect dwindling natural resources. Improvements in source materials, product durability and end-of-life disposal procedures can create consumer products that are better for the Earth throughout their lifecycles. Three recent advancements hope to make a difference.

Read More Show Less

EcoWatch Daily Newsletter

A net-casting ogre-faced spider. CBG Photography Group, Centre for Biodiversity Genomics / CC BY-SA 3.0

Just in time for Halloween, scientists at Cornell University have published some frightening research, especially if you're an insect!

The ghoulishly named ogre-faced spider can "hear" with its legs and use that ability to catch insects flying behind it, the study published in Current Biology Thursday concluded.

"Spiders are sensitive to airborne sound," Cornell professor emeritus Dr. Charles Walcott, who was not involved with the study, told the Cornell Chronicle. "That's the big message really."

The net-casting, ogre-faced spider (Deinopis spinosa) has a unique hunting strategy, as study coauthor Cornell University postdoctoral researcher Jay Stafstrom explained in a video.

They hunt only at night using a special kind of web: an A-shaped frame made from non-sticky silk that supports a fuzzy rectangle that they hold with their front forelegs and use to trap prey.

They do this in two ways. In a maneuver called a "forward strike," they pounce down on prey moving beneath them on the ground. This is enabled by their large eyes — the biggest of any spider. These eyes give them 2,000 times the night vision that we have, Science explained.

But the spiders can also perform a move called the "backward strike," Stafstrom explained, in which they reach their legs behind them and catch insects flying through the air.

"So here comes a flying bug and somehow the spider gets information on the sound direction and its distance. The spiders time the 200-millisecond leap if the fly is within its capture zone – much like an over-the-shoulder catch. The spider gets its prey. They're accurate," coauthor Ronald Hoy, the D & D Joslovitz Merksamer Professor in the Department of Neurobiology and Behavior in the College of Arts and Sciences, told the Cornell Chronicle.

What the researchers wanted to understand was how the spiders could tell what was moving behind them when they have no ears.

It isn't a question of peripheral vision. In a 2016 study, the same team blindfolded the spiders and sent them out to hunt, Science explained. This prevented the spiders from making their forward strikes, but they were still able to catch prey using the backwards strike. The researchers thought the spiders were "hearing" their prey with the sensors on the tips of their legs. All spiders have these sensors, but scientists had previously thought they were only able to detect vibrations through surfaces, not sounds in the air.

To test how well the ogre-faced spiders could actually hear, the researchers conducted a two-part experiment.

First, they inserted electrodes into removed spider legs and into the brains of intact spiders. They put the spiders and the legs into a vibration-proof booth and played sounds from two meters (approximately 6.5 feet) away. The spiders and the legs responded to sounds from 100 hertz to 10,000 hertz.

Next, they played the five sounds that had triggered the biggest response to 25 spiders in the wild and 51 spiders in the lab. More than half the spiders did the "backward strike" move when they heard sounds that have a lower frequency similar to insect wing beats. When the higher frequency sounds were played, the spiders did not move. This suggests the higher frequencies may mimic the sounds of predators like birds.

University of Cincinnati spider behavioral ecologist George Uetz told Science that the results were a "surprise" that indicated science has much to learn about spiders as a whole. Because all spiders have these receptors on their legs, it is possible that all spiders can hear. This theory was first put forward by Walcott 60 years ago, but was dismissed at the time, according to the Cornell Chronicle. But studies of other spiders have turned up further evidence since. A 2016 study found that a kind of jumping spider can pick up sonic vibrations in the air.

"We don't know diddly about spiders," Uetz told Science. "They are much more complex than people ever thought they were."

Learning more provides scientists with an opportunity to study their sensory abilities in order to improve technology like bio-sensors, directional microphones and visual processing algorithms, Stafstrom told CNN.

Hoy agreed.

"The point is any understudied, underappreciated group has fascinating lives, even a yucky spider, and we can learn something from it," he told CNN.

Trending

There are many different CBD oil brands in today's market. But, figuring out which brand is the best and which brand has the strongest oil might feel challenging and confusing. Our simple guide to the strongest CBD oils will point you in the right direction.

Read More Show Less
Financial institutions in New York state will now have to consider the climate-related risks of their planning strategies. Ramy Majouji / WikiMedia Commons

By Brett Wilkins

Regulators in New York state announced Thursday that banks and other financial services companies are expected to plan and prepare for risks posed by the climate crisis.

Read More Show Less
The left image shows the OSIRIS-REx collector head hovering over the Sample Return Capsule (SRC) after the Touch-And-Go Sample Acquisition Mechanism arm moved it into the proper position for capture. The right image shows the collector head secured onto the capture ring in the SRC. NASA / Goddard / University of Arizona / Lockheed Martin

A NASA spacecraft has successfully collected a sample from the Bennu asteroid more than 200 million miles away from Earth. The samples were safely stored and will be preserved for scientists to study after the spacecraft drops them over the Utah desert in 2023, according to the Associated Press (AP).

Read More Show Less

Support Ecowatch