landscape

Danger For North American Biomes | Earth Wise

October 8, 2020 By EarthWise Leave a Comment

Biomes are large, naturally occurring communities of flora and fauna that occupy a major habitat. Examples include several different kinds of forests, grasslands, deserts, and tundra. According to a new study published in the journal Global Change Biology, the resilience of North America’s plant biomes is declining, which means that they are in danger of succumbing to a major extinction event.

The research analyzed over 14,000 fossil pollen samples from 358 sites across North America for the purpose of reconstructing their “landscape resilience”, meaning the ability of the habitats to persist or quickly rebound in response to disturbances.

Some 13,000 years ago, North American ecosystems were destabilized by the one-two punch of the retreat of glaciers at the end of the last ice age along with the arrival of humans. That combination resulted in the extinction of large terrestrial mammals on the continent.

Today, there is a comparable one-two punch created by the rapidly changing climate combined with the dramatic expansion of the footprint of human civilization. The result could again be the demise of some of North America’s biomes. In past eras, forests persisted longer than grasslands, but also took longer to reestablish after disruptions. Overall, only 64% of historic biomes regained their original ecosystem type.

The scientists said that strategic conservation effects could help counteract or slow down the impacts of climate change in the coming decades. In particular, efforts focusing on improving landscape and ecosystem resilience by increasing local connectivity and concentrating on regions with high richness and diversity could have the greatest positive effect.

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North American Biomes Are Losing Their Resilience, With Risks for Mass Extinctions

Photo, posted January 9, 2020, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Alaska Is Getting Wetter | Earth Wise

August 31, 2020 By EarthWise Leave a Comment

Siberia has been in the news for record-setting heat waves and wildfires, but it is not the only northern region experiencing unusual weather. Alaska, apart from setting its own warm weather records, is experiencing the rainiest five years in its century-long meteorological record.

Extreme weather in the Arctic is being driven by an aspect of climate change called Arctic amplification, which leads to temperatures rising faster than the global average. The physical basis of Arctic amplification is well understood, but its effects over time are much less predictable.

The past five years included two summers with average precipitation, one that was a little drier than usual, and two of the wettest summers on record. Researchers have taken measurements of how far below the surface permafrost has thawed by the end of summer over a wide range of Alaskan environments.

About 85% of Alaska sits upon permafrost and the increasing rainfall over the past five years is leading to a deeper thaw of permafrost across the state. The wettest summer on record was 2014 and permafrost didn’t freeze back to previous levels even when the next couple of summers were relatively drier.

The study demonstrated how different types of land cover govern relationships between summer rainfall and permafrost thaw. As Alaska becomes warmer and wetter, the vegetation cover is projected to change, and the increasing occurrence of wildfires will disturb larger areas of the landscape. These conditions are likely to lead to a feedback loop driving more and more permafrost thawing.

Fundamental changes to Alaskan ecosystems are occurring on an unprecedented timescale – not gradually over decades or lifetimes, but over mere months or years.

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Alaska is getting wetter. That’s bad news for permafrost and the climate.

Photo, posted June 10, 2011, courtesy of Peter Rintels via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Beavers And The Warming Arctic | Earth Wise

August 5, 2020 By EarthWise Leave a Comment

Beavers have a remarkable ability to transform landscapes. Using their sharp teeth, they fell trees and shrubs and build dams, which cause small valleys to fill with water and form new lakes. Some of these lakes measure five or ten acres in size, or even more. And beavers are very efficient builders; they often build their dams at precisely those points where can they have the greatest effect with the least effort.

Scientists studying beaver activity in the Arctic regions of Alaska have found that the changing climate is leading to a substantial increase in beaver populations and their effect on the landscape.

In 2018, researchers found that the beavers living in a 7,000 square-mile area in northwest Alaska had created 56 new lakes in just five years. Thanks to rising temperatures, more and more habitats offer the shrubs that beavers need for food and building material. In addition, the lakes, which used to freeze solid, now offer beaver-friendlier conditions. Also, beavers are not hunted as intensively as in the past.

The scientists were surprised that beavers have seized the opportunity so intensively. There is basically an exponential growth in beaver dams. This is actually a worrisome situation. Forming all these new lakes degrades ice-rich permafrost in the area. In the Kotzebue region of Alaska, the overall water area has increased by more than 8% over the past 17 years, and roughly two-thirds of that is due to beavers.

The degradation of the Arctic’s permafrost is a dangerous situation and it appears that anyone who wants to predict its future has to keep the activity of beavers in mind.

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Beavers gnawing away at the permafrost

Photo, posted June 23, 2018, courtesy of Becky Matsubara via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Dams Restores Ecosystems

November 1, 2019 By EarthWise Leave a Comment

In many parts of the country, dams that sometimes date back as much as 100 years are being removed and are giving way to the revival of migratory fish and their river ecosystems. Since 1912, more than 1,600 dams have been removed in the U.S., but the pace of dam removal has greatly picked up in recent years. 2017 and 2018 were the highest years ever with 91 and 99 dams removed, respectively.

When dams are removed, the response from migratory fish can be almost immediate. A large dam removal project on the Penobscot River in Maine in 2012 opened up 1,000 miles of habitat with a quick return of shad and alewives, followed by salmon.

In 2022, four large dams across the Klamath River will be removed. The dams, which are located at the California and Oregon border, were facing an expensive re-licensing process and, because of their age, could no longer be run at a profit.

Re-licensing the dams along the Klamath was going to cost as much as $400 million. On the other hand, uncapping the Klamath River has tremendous commercial and tourism potential. Two states, tribal nations, and other stakeholders have all seen the virtues of restoring the landscape to its original form.

Opposition to dam removal is typically driven by aesthetics or recreational preferences. But dam economics are getting increasingly worse. Now that electricity can be produced far more cheaply with wind and solar power, many American dams have become artifacts of an older manufacturing era. Meanwhile, rural towns near decommissioned dams are likely to now have more robust fishing industries.

In rivers big and small, migratory fish and river ecosystems surge back to life as old energy structures are taken down.

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Take Down That Dam: River Ecosystems Bounce Back As Removals Soar

Photo, posted June 11, 2016, courtesy of the Bureau of Land Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Degraded Permafrost In The Arctic

July 11, 2019 By EarthWise Leave a Comment

Permafrost is defined as rock or soil that has been at or below the freezing point of water for two or more years. Most of it is located in high latitudes in and around the Arctic and Antarctic regions. Permafrost covers nearly a quarter of the exposed land in the Northern Hemisphere.

Permafrost can contain many different materials including bedrock, sediment, organic matter, water and ice. Because of the presence of organic matter, permafrost is potentially the source of significant methane emissions if it thaws and the trapped biomass begins to rot.

A recent study looked at the results of 30 years of aerial surveys and extensive ground mapping of an area of Canada’s high Arctic polar desert known as the Eureka Sound Lowlands. This area has an extremely cold climate and the permafrost there is over 1/3 of a mile thick. It has long been assumed that this landscape was stable.

Research led by McGill University in Montreal has found that this is not the case. The increases in summer air temperatures seen in recent years are initiating widespread changes in the landscape.

A particular landform known as a retrogressive thaw slump that forms when ice within permafrost melts and the land slips down is widely occurring in the area. The absence of vegetation and layers of organic soil in these polar deserts make permafrost in the area particularly vulnerable to increases in summer air temperatures.

The research indicates that despite the cold polar desert conditions that characterize much of the high Arctic, the interaction between ice-rich permafrost systems and climate factors is complex and the links between global warming and permafrost degradation are not well understood.

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Widespread permafrost degradation seen in high Arctic terrain

Photo, posted August 11, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

High-Tide Flooding And Pollution

April 30, 2019 By EarthWise Leave a Comment

Global sea levels are steadily rising. They are up 8 inches in the past century and now increasing at an average of 1.3 inches per decade. As a result, the incidence of high-tide “sunny day” flooding is on the rise, especially along the U.S. East Coast.

Norfolk Virginia experienced fewer than 2 days of high-tide flooding a year in the 1960s; it had 14 in 2017. Up and down the East Coast, flood days have increased by factors of 5 and more.

This has led to a form of pollution that hasn’t gathered much attention in the past: when these floodwaters recede, they can carry debris, toxic pollutants and excess nutrients into rivers, bays, and oceans.

In the aftermath of high-tide flooding in Norfolk, Chesapeake Bay was littered with tipped-over garbage cans, tossed-away hamburgers, oil, dirty diapers, pet waste and all manner of other things. Water that comes up on the landscape takes everything back into the river or ocean with it.

Analysis of tidal flooding along the Lafayette River in Norfolk indicated that just one morning of tidal flooding poured nearly the entire EPA annual allocation of nitrogen runoff for the river – nearly 2,000 pounds – into Chesapeake Bay. The effects of excess nitrogen in the water are well-known and responsible for the toxic algal blooms that endanger aquatic life as well as human health.

According to the National Oceanic and Atmospheric Administration, high-tide flooding frequency along the southeastern coast of the U.S. rose 160% since 2000. With the expected continuing rises in sea level, NOAA projects that as many as 85 days of high-tide flooding will occur along the coast by the year 2050. It’s a big problem.

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As High-Tide Flooding Worsens, More Pollution Is Washing to the Sea

Photo, posted September 20, 2018, courtesy of SC National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fire-Driven Thunderstorms

March 6, 2019 By EarthWise Leave a Comment

In 2016 and 2017, wildfires in western Canada spawned thunderstorms that ignited additional fires, in some cases tens of miles away from the original fire. These fire-triggered thunderstorms are technically known as pyrocumulonimbus clouds, or “pyroCb’s”.

The physics of pyroCb’s is complex. When super-heated updrafts from an intense fire suck smoke, ash, burning materials, and water vapor high into the air, these elements cool and form so-called fire clouds that look and act like the cumulonimbus clouds associated with classic thunderstorms. What is different is that the heat and particulates in the smoke almost always arrest the ability of the cloud to produce rain. Instead, what remains is a lightning storm that moves across the landscape, triggering more fires.

These PyroCb events appear to be happening far more often, producing more energy, and erupting in places where they have never been seen before. As the world warms, wildfires themselves are becoming larger and hotter. In the past decade, wildfires have been burning more than twice as many acres as they did before the turn of the 21^st century. Along with the growth in wildfire activity, there has been an increase in PyroCb events, and there are now an average of 25 per year in western North America.

Apart from starting new fires, pyroCb’s also have similar effects as moderate-sized volcanic eruptions. Smoke and aerosols from wildfires can rise high into the stratosphere, where they can linger for months. Eventually, the particles carried aloft in the atmosphere do come down, dumping dangerous chemicals on far flung regions of the earth. But unlike volcanic eruptions, which are relatively rare events, pyroCb’s are happening more and more each year.

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Fire-Induced Storms: A New Danger from the Rise in Wildfires

Photo, posted July 31, 2013, courtesy of Loren Kerns via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bring The Wild Back Into Farmlands

December 4, 2018 By EarthWise Leave a Comment

A recent study published in Science looks at the effects of maintaining at least a little bit of the wild on working lands including farmland, rangeland and forests. The study concludes that doing so may be a key to preserving biodiversity in the face of climate change.

Shifting Climate Zones

November 16, 2018 By EarthWise Leave a Comment

As the climate warms, the planet’s landscape is changing. The Arctic ice is shrinking, the ocean is rising altering coastlines, and plants, animals and diseases are on the move. The world’s climate zones are changing in significant and measurable ways.

Throwing Off Nature’s Seasonal Clock

October 29, 2018 By EarthWise Leave a Comment

Ecosystems throughout the Arctic are regulated by seasonal changes leading to a finely tuned balance between the greening of vegetation and the reproduction of animals. The rapidly warming climate and the disappearing sea ice are upending that balance.

Antarctica Is Getting Greener

June 29, 2017 By EarthWise

The frozen landscape of Antarctica is getting greener. Researchers drilling into layers of moss that have been accumulating in Antarctica over the last 150 years have found that the growth rate of the moss has been speeding up over the past 50 years.

Changing National Parks

January 12, 2017 By EarthWise

America’s National Parks are special places of incomparable beauty and fascination. When the National Park Service was first created 100 years ago, it was instructed to leave these places “unimpaired for the enjoyment of future generations.” We now live in a time when the changing climate is altering many aspects of the landscape including in many national parks. The parks are protected, but they are changing.

Ecology And Designing Future Cities

January 4, 2016 By WAMC WEB

When most people hear the word ‘ecology’ – chances are it conjures up images of scientists working in distant, wild landscapes, such as old growth forests or remote mountain lakes. Increasingly, however, ecological studies are focused on urban and suburban areas.

Solar Power And The Landscape

October 5, 2015 By EarthWise

The use of solar power is growing rapidly but with all the growth, solar power only provides 1% of the country’s electricity. On the other hand, in 2014, solar power accounted for almost a third of all the new US electric generating capacity. According to the International Energy Agency, solar power could be the world’s leading source of electricity by the year 2050.