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Greenland is greening

March 21, 2024 By EarthWise Leave a Comment

Despite their names, Iceland is very green, and Greenland is very icy. But in Greenland, that is changing. Temperatures in the world’s largest island are rising twice as fast as they are in the rest of the world and, as a result, the icy rocky landscape is turning increasingly green.

Satellite records reveal that over the last three decades Greenland has lost 11,000 square miles of ice, which is an area about the size of Massachusetts. As the ice melts off, tundra and shrublands takes its place. The ice melt moves sediment and silt and eventually wetlands and fenlands are formed.

Between the late 1980s and the late 2010s, the areas of Greenland covered by vegetation have more than doubled. The new green areas cover roughly 33,000 square miles, which is an area the size of Maine.

Greenland’s dramatic changes are the result of the warming climate, but in turn, those changes are accelerating climate change. Land covered with dark green vegetation absorbs more energy from the sun thereby warming the air whereas ice-covered landscapes reflect much of the sun’s energy back into space. In addition, the rapidly expanding wetlands are a significant source of methane, which traps even more heat in the atmosphere.

Greenland is a poster child for the effects of climate change. Its glaciers and icecaps are shrinking, glacier-fed lakes are expanding, permafrost lakes are draining, and rivers are transporting vast amounts of sediment and widening. All of this is going on as its vegetation cover and species diversity is expanding.

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In Icy Greenland, Area Covered by Vegetation Has More Than Doubled in Size

Photo, posted September 20, 2019, courtesy of Amanda via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Bengal Water Machine | Earth Wise

October 31, 2022 By EarthWise Leave a Comment

Over the past three decades, the owners of 16 million small farms in the Bengal Basin of Bangladesh have been pumping shallow groundwater during dry seasons to irrigate rice paddies. By lowering groundwater levels in this way during the dry season, the ability of leakage from rivers, lakes, and ponds to replenish the groundwater was greatly enhanced. Capturing surface water not only improved the recovery of groundwater levels but only helped to reduce flooding during monsoons.

The net result of this enormous collective groundwater pumping by millions of farmers has been the creation of vast natural reservoirs underground that are comparable to what is contained by many of the world’s largest dams. This system of sustaining irrigation has transformed what was previously a famine-prone country into a food-secure nation.

The details of this remarkable transformation have been laid out in a study by University College London recently published in the journal Science. According to the study, over the course of 30 years, more than 75 cubic kilometers of fresh water was captured by this process, which is equivalent to the combined reservoirs of China’s Three Gorges Dam and the Hoover Dam in the U.S.

The authors of the study described the water cycling process as “The Bengal Water Machine” and argue that it can be a sustainable alternative to conventional approaches to seasonal river flow storage for irrigation, which typically involve dams and reservoirs. Such approaches are difficult to implement in densely populated alluvial plains where sand, silt, and clay are laid down by annual floodwaters.

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Millions of farmers “replumb” world’s largest delta

Photo, posted February 2, 2010, courtesy of Melanie Ko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Living On Trash | Earth Wise

March 16, 2021 By EarthWise Leave a Comment

Litter is persistent and widespread in rivers worldwide. The world’s major rivers and estuaries are hotspots for plastic waste. Trash and microparticles wash down tributaries and build up before rivers enter oceans.

New research published in the journal Freshwater Biology has found that as this waste accumulates, aquatic river species like insects and snails are increasingly choosing to settle on plastic rather than on natural features like rocks and fallen branches.

Researchers from the University of Nottingham in the UK collected plastic waste from three rivers in eastern Britain along with rocks from the same rivers. Their analysis of all the macroinvertebrates on the items’ surfaces found that the surfaces of plastic waste items had nearly four times the diversity of the small animals as did the rocks. In addition, the more complex the plastic’s surface was, the higher the diversity.

The growing abundance of plastic waste coincides with a decline in natural habitat features in urban rivers. This is a result of increasing amounts of sedimentation from development that blankets riverbeds in silt and sand, restricting the supply and movement of rocks, fallen tree branches, and aquatic plants.

Clearly litter can serve as a place for various species to colonize, but trash is not a good environment for them. Trash can release toxic chemicals and entangle animals. Microplastics pose risks for the animals if ingested.

Estimates are that between 1.15 and 2.41 million tons of plastic waste enter the ocean every year from rivers around the world. Natural habitats have become rare in urban rivers. River ecosystems built around piles of trash are not a good thing.

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As Plastic Pollution in Rivers Gets Worse, Species Are Increasingly Living on Litter

Photo, posted August 17, 2010, courtesy of Renee_McGurk via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Permafrost | Earth Wise

February 26, 2020 By EarthWise Leave a Comment

The Arctic is warming faster than any region on Earth and mostly we’ve been hearing about the rapid disappearance of Arctic sea ice. But the land in the Arctic is also undergoing major changes, especially to the permafrost that has been there for millennia.

Permafrost occurs in areas where the temperature of the ground remains below freezing for two years or more. About a quarter of the Northern Hemisphere’s landscape meets this criterion. Most of the world’s permafrost is found in northern Russia, Canada, Alaska, Iceland, and Scandinavia.

Permafrost regions previously carpeted in cranberries, blueberries, shrubs, sedges, and lichen are now being transformed into nothing but mud, silt, and peat. So-called regressive thaw slumps – essentially landslides – are creating large craters in the landscape. (The Batagaika Crater in the Yana River Basin of Siberia is a kilometer long and 100 meters deep).

Apart from the violence being done to the Arctic landscape, the greatest concern is that the permafrost has locked in huge stores of greenhouse gases, including methane, carbon dioxide, and nitrous oxide. It is estimated that the permafrost contains twice as much carbon as is currently contained in the atmosphere. As the permafrost thaws, these gases will be released. With them will be pathogens from bygone millennia whose impact cannot be predicted. Climatologists estimate that 40% of the permafrost could be gone by the end of the century.

As the permafrost thaws, the region’s ecosystems are changing, making it increasingly difficult for subsistence indigenous people and Arctic animals to find food. Landslides are causing stream flows to change, lakes to suddenly drain, seashores to collapse, and water chemistry to be altered.

The warming Arctic is about much more than disappearing sea ice.

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How Thawing Permafrost Is Beginning to Transform the Arctic

Photo, posted February 9, 2017, courtesy of the U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring Sediment To Save Wetlands

August 25, 2017 By EarthWise

The world’s rivers carry billions of cubic yards of sediment – sand, silt and other material – and transport it to wetlands and coastal areas. Until fairly recently, this was viewed as a negative thing. But that has changed.