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Regrowing forests naturally

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Deforestation is one of the major causes of climate change and restoring and enhancing forests is a major activity around the world as a way to mitigate its effects.  There are high-profile initiatives to plant millions of trees, but these projects are often ill-conceived and poorly managed.

One of the most dramatic failures was the planting of over a million mangrove seedlings on the Filipino island of Luzon back in 2012.  A study 8 years later found that fewer than 2 percent of the trees had survived.  The rest died or were washed away.

The causes of failure in tree planting programs include planting of trees that become vulnerable to disease, competing demands for land, changing climate, planting in areas not previously forested, and a lack of aftercare including watering seedlings.

A multinational study recently published in Nature has found that forests could regrow naturally on more than 800,000 square miles of land around the tropics without the need for planting trees by hand.  This is an area larger than Mexico.

The researchers mapped areas where forests would be likely to regrow – areas where soils are healthy and where there is already forest nearby to supply seeds.  In some places, lands are so degraded that it is necessary to plant trees by hand, but this is costly and prone to failure.  Forests that regrow naturally tend to fare better and make better habitats for wildlife.

The effect of regrown forests on the climate would be very substantial.  If these forests were allowed to grow for three decades, they would absorb enough carbon to offset 50 years of emissions by Australia, the home of the lead researcher of the study. 

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Tropical Forests Could Regrow Naturally on Area the Size of Mexico

Photo, posted February 16, 2018, courtesy of Jason Houston / USAID via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Brownfields and solar power

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Brownfields are blighted lands that have suffered environmental contamination, making it very difficult to redevelop them or make good use of them.  Generally, they are previously used lands that have the presence or at least the potential presence of hazardous substances, pollutants, or other contaminants at levels exceeding health-based or environmental standards.  There are nearly half a million brownfields in the U.S. that are ripe for repurposing.

One very attractive use for brownfields is to convert them to “brightfields,” which is the colloquial term for brownfields redeveloped into solar projects.  Estimates are that nearly 200,000 U.S. brownfield sites are eligible for brightfield conversion, which could provide hundreds of gigawatts of energy production.  Over 10,000 of these sites are inactive landfills, which alone could power 8 million homes.  Many of these sites have sat unused for decades.

A recent success story took place in Old Bridge Township, New Jersey where an abandoned waste site – designated a Superfund site by the EPA for decades – has now become a solar project that will generate more than $1.2 million a year for the township and will provide reduced-cost electricity for 400 homes, half of which are low- and moderate-income residents.

The site was on the EPA list of Superfund National Priorities , meaning it was considered one of the most serious abandoned hazardous waste sites.  Such sites required continuous monitoring, modifications, and cleanup. 

Projects like the Old Bridge solar project are likely to become increasingly common in the future, as legacy liabilities can be turned into valuable assets.

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How solar installations give new life to blighted brownfields

Photo, posted November 11, 2015, courtesy of Martin Malec via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fungus And Carbon Storage | Earth Wise

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It is well-known that plants and trees store enormous amounts of carbon.  What has not been common knowledge is that the vast underground network of fungi across the world’s lands stores billions of tons carbon, roughly equivalent to 36% of yearly global fossil fuel emissions.

These mycorrhizal fungi form symbiotic relationships with almost all land plants.  The fungi transport carbon, converted by sugars and fats by plants, into soil.  They have been supporting life on land for at least 450 million years and form sprawling underground networks everywhere – even beneath roads, gardens, and houses – on every continent on earth.

An international team of scientists analyzed hundreds of studies looking at plant-soil processes to understand how much carbon is being stored by fungi on a global scale.  The findings, published in the journal Current Biology, revealed that over 13 billion tons of CO2 is transferred from plants to fungi each year, more than China emits annually.  This process transforms the soil beneath our feet to a massive carbon pool and constitutes the most effective carbon storage activity in the world.

Given that fungi have such a crucial role in mitigating carbon emissions, the researchers are recommending that fungi should be considered in biodiversity and conservation policies. More needs to be done in protecting the underground networks of mycorrhizal fungi. The UN has warned that human activities are degrading soils and that 90% of the world’s soils could be degraded by 2050.  Not only would this obviously be very bad for the productivity of crops and plants, but we now know this could be catastrophic for curbing climate change and rising temperatures.

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Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero

Photo, posted May 28, 2023, courtesy of Geoff McKay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rewilding The American West | Earth Wise

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Oregon State University scientists have proposed a series of management changes for western federal lands aimed at re-establishing ecosystems there.  Their proposal would result in more gray wolves and beavers in nearly 200,000 square miles of federal lands in 11 states.

In each of those states, the researchers identified areas containing prime wolf habitat.  Gray wolves were hunted to near extinction in the West but have been gradually reintroduced in some areas starting in the 1990s.  Wolf restoration offers significant ecological benefits by helping to naturally control the population of grazing animals such as elk.  This in turn facilitates the regrowth of vegetation species such as aspen, which ultimately supports diverse plant and animal communities.

Beaver populations, which used to be robust across the West, declined roughly 90% after settler colonialism and are now nonexistent in many areas.  By felling trees and shrubs and constructing dams, beavers enrich fish habitat, increase water and settlement retention, maintain water flows during droughts, and increase carbon sequestration.

According to the researchers, the biggest threat to these western lands is livestock grazing, which has degraded ecosystems to a great extent.  They recommend the removal of grazing on about 30% of the federal lands being used for that purpose and instead would have rewilding efforts go on. 

The American West is going through a period of converging crises including extended drought and water scarcity, extreme heat waves, massive fires, and loss of biodiversity.  Rewilding is a way to reestablish long-standing ecosystems.

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More wolves, beavers needed as part of improving western United States habitats, scientists say

Photo, posted October 1, 2020, courtesy of Tina DaPuglet via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Land Use Change And Flooding | Earth Wise

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Land use change refers to the conversion of a piece of land’s use by humans from one purpose to another. Land use change is commonly associated with biodiversity loss and increased greenhouse gas emissions.  But how does land use change impact water cycles? 

According to researchers from the University of Göttingen in Germany, IPB University, and BMKG (both in Indonesia), the expansion of monocultures, such as rubber and oil palm plantations, leads to more frequent and more severe flooding.  The researchers explain the increase in flooding “with a complex interplay of ecohydrological and social processes, including soil degradation in monocultures, the expansion of oil palm plantations into wetlands, and the construction of flood protection dams.” 

For the study, which was recently published in the journal Ecology & Society, the research team interviewed nearly 100 Indonesian farmers, villagers, and decision-makers in Sumatra.  The team supplemented its research with data on precipitation, river and groundwater levels, soil properties, and regional mapping. 

During large-scale land use change – like plantation expansions – newly-compacted soil causes rainwater to runoff as opposed to being absorbed.  As more plantations are established in floodplains, the owners try to control flooding on their land by building barriers.  But these dams often lead to increased flooding on neighboring lands.  This understandably triggers social tensions between other farmers and plantation owners.     

In order to reduce the negative impact of land use change on the water cycle, the research team suggests soil protection and improved planning – especially in floodplains – would be a good place to start.  

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Land use change leads to increased flooding in Indonesia

Photo, posted October 8, 2018, courtesy of Artem Beliaikin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Crop Diversity

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A study at the University of Toronto suggests that on a global scale, we are growing more of the same kinds of crops, and this diminishing diversity presents major challenges for agricultural sustainability.

In some places, for example here in North America, crop diversity has actually increased.  Back in the 1960s, North Americans grew about 80 crops.  Now there are 93.

But on a global scale, more of the same kinds of crops are being grown on much larger scales.  Just four crops – soybeans, wheat, rice and corn – occupy nearly 50% of the world’s entire agricultural lands.  The remaining 152 crops cover the rest.  Large industrial farms often grow one crop species – usually just a single genotype – across thousands of acres of land.

This decline in global crop diversity is problematic in several ways.  On a cultural level, it threatens regional food sovereignty.  If regional crop diversity is threatened, it makes it more difficult for people to eat or afford foods that are culturally significant to them.

On an ecological level, the dominance by a few genetic lineages of crops makes the agricultural system increasingly susceptible to pests or diseases.  The deadly fungus that is threatening the world’s banana plantations is a prime current example.  The Irish potato famine in the 19th century is a tragic historical example.

As large industrial-sized farms in Asia, Europe and the Americas start to look more and more alike, the dangers of large monocultures of crops that are commercially valuable will only increase.  It will be important for global governments to consider the impact of policies that affect the diversity of the agricultural system and its sustainability in an increasingly hungry world.

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A small number of crops are dominating globally. And that’s bad news for sustainable agriculture

Photo, posted August 13, 2012, courtesy of Alasdair McKenzie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cold Weather In A Warming Climate

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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.

[Read more…] about Cold Weather In A Warming Climate

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