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Disappearing Rainforests | Earth Wise

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Forest loss is a major contributor to climate change, and it is continuing at a rapid pace.  The tropics lost about 30 million acres of tree cover in 2019, a third of which was within humid tropical primary forests, which are especially important for biodiversity and carbon storage.  To put that loss in a human-scale perspective, it is the equivalent of losing a football field of primary forest every six seconds for the entire year.

The losses last year were 2.8% higher than in the previous year, and these losses have continued over the past 20 years despite worldwide efforts to halt deforestation.  

Brazil single-handedly accounted for over a third of all global loss of humid tropical primary forests. Bolivia experienced record-breaking tree cover loss due to fires.  The losses in its forests were 80% greater than in any previous year.  The fires were often started by people who were trying to clear land for agriculture but had the fires go out of control. Several countries in Africa’s Congo Basin also experienced sustained or worsening forest loss. 

Indonesia, often the focus of the world’s attention for its deforestation activities, actually saw a 5% reduction in primary forest loss in 2019.  It was the third year in a row for lower losses.  The now-permanent moratorium on clearing forests for oil palm plantations and logging seems to be working.

Going forward, the coronavirus pandemic poses additional threats to the world’s forests in the near future.  There may be a tendency to sacrifice forests in pursuit of economic recovery, which will only lead to future complications for the health and livelihoods of millions of people around the world.

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We Lost a Football Pitch of Primary Rainforest Every 6 Seconds in 2019

Photo, posted February 7, 2011, courtesy of Chad Skeers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Dangerous Smoke From Australia’s Wildfires | Earth Wise

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Wildfires raging across Australia have devastated large swathes of land and prompted one of the largest evacuations in the country’s history.  The fires, which have scorched approximately 20 million acres, have also killed 27 people and affected an estimated one billion animals at the time of this recording. The fire season, though still young, already ranks as among the worst in Australia’s recorded history. 

Away from the flames, millions more in Australia are breathing unhealthy air as a result of the smoke from these wildfires. Wildfires release all sorts of dangerous air pollutants, like carbon monoxide and nitrous oxide.  But wildfires also release fine particulate matter (more commonly referred to as PM2.5), which can be transported long distances.  Breathing in these microscopic particles can lead to respiratory and cardiovascular problems.  High levels of PM2.5 are particularly harmful to older people, young children, and those with weakened immune systems.  

The Australian capital city of Canberra has been covered in a thick haze of smoke from nearby wildfires.  Canberra recorded its worst air quality day on January 2nd, when levels of PM2.5 spiked to more than 200 micrograms per cubic meter during the worst hour.

Smoke has also been fouling Sydney’s air off and on for months, with PM2.5 readings hitting nearly 400 micrograms per cubic meter last month during the highest hour of pollution. 

The U.S. EPA has in place an annual PM2.5 standard of 12 micrograms per cubic meter and a daily (or 24 hour) standard of 35. 

According to the IPCC, southern Australia is expected to see increased risk of fire as the planet continues to warm.  Regrettably, this could be the new normal. 

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Millions of Australians Are Choking on Smoke From Wildfires

Photo, posted December 5, 2019, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Predicting Lightning Strikes

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Lightning is one of the most unpredictable phenomena in nature.  Approximately 100 lightning bolts strike earth’s surface every second, and each lightning bolt can contain up to one billion volts of electricity.  Lightning regularly kills both people and animals and sets homes and forests on fire.  It’s also been known to ground airplanes. 

Researchers at EPFL – a research institute and university in Switzerland – have developed a novel way to predict where and when lightning will strike.  The system relies on a combination of standard data from weather stations and artificial intelligence to predict lightning strikes to the nearest 10 to 30 minutes and within a radius of less than 20 miles.  The simple and inexpensive system was outlined in a research paper recently published in Climate and Atmospheric Science, a Nature partner journal.   

According to researchers, the current systems for predicting lightning strikes are slow, expensive, and complex, relying on external data acquired by satellite and radar.  The new inexpensive system from EPFL uses real time data that can be obtained from any weather station, meaning it can cover remote regions that are out of radar and satellite range and where communication networks are lacking.  The quick predictions from the system allow alerts to be issued before a storm has even formed. 

The system uses a machine-learning algorithm that’s been trained to recognize conditions that lead to lightning.  The researchers took into account atmospheric pressure, air temperature, relative humidity, and wind speed, among other things.  After training the algorithm, the system was able to predict lightning strikes accurately nearly 80% of the time.

This system is a simple way to predict a complex phenomenon. 

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Using AI to predict where and when lightning will strike

Photo, posted December 14, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildfires And Carbon

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This summer has been an unprecedented year for fires in the Arctic.  Major fires have burned throughout the Arctic in Russia, Canada, and Greenland.  In total these fires released 50 million tons of carbon dioxide in June alone, which is as much as Sweden emits in an entire year.

In an average year, wildfires around the world burn an area equivalent to the size of India and emit more carbon dioxide to the atmosphere than global road, rail, shipping and air transport combined.

Ordinarily, this is part of a natural cycle.  As vegetation in burned areas regrows, it draws CO2 back out of the atmosphere through photosynthesis.  This is part of the fire-recovery cycle, which can take less than a year in grasslands, but decades in forests.  But in Arctic or tropical peatlands, full recovery may not occur for centuries.

A recent study looked at and quantified the important role that charcoal plays in helping to compensate for carbon emissions from fires.  In wildfires, some of the vegetation is not consumed by burning, but instead is transformed to charcoal – referred to as pyrogenic carbon.   This carbon-rich material can be stored in soils and oceans over very long time periods.

Researchers have combined field studies, satellite data, and modelling to quantify the amount of carbon that is placed in storage in the form of charcoal.  Their results are that the production of pyrogenic carbon amounts to about 12% of the CO2 emissions from fires and can be considered a significant buffer for landscape fire emissions.

Charcoal does not represent a solution to the problem of increasingly intense wildfires, but it is important to take it into account in understanding what is happening.

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How wildfires trap carbon for centuries to millennia

Photo, posted August 17, 2018, courtesy of the Bureau of Land Management Oregon and Washington via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of The Amazon Rainforest Fires

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The Amazon rainforest covers extensive parts of Brazil, Peru, Colombia, and small parts of six other countries.  It is the largest rainforest in the world and is instrumental in driving the weather and climate in South America.

The raging wildfires in the Amazon rainforest are a source of great concern.  The Amazon is always prone to wildfires during the dry season in South America, but the extent and number of fires this year cannot be attributed simply to drought.  The surge in fires has come from illegal deforestation by loggers and farmers, who are using the cleared-out land for cattle ranching.

Rainforests produce consistently high amounts of rainfall throughout the year by pulling water from the soil and then releasing it into the atmosphere.  The Amazon rainforest essentially makes it rain in South America. 

Over time, the forest plays a crucial role in cycling carbon out of the atmosphere by turning it into biomass.  The Amazon jungle sucks up as much as a quarter of the planet’s atmospheric carbon dioxide.

Pristine rainforest burns less frequently and less intensely than cleared and recovering forest.  As more and more of the Amazon rainforest is deforested, it becomes more likely to burn each year.

The major disruption of the water dynamics in South America has the potential to not only drive the weather in South American countries but even potentially influence natural resources like snow packs in the Northern Hemisphere.

The skies of Sāo Paulo, Brazil’s financial hub have been dark at midday because of the Amazon fires.  This is like having a fire in California and seeing the smoke in Boston.  The Amazon rainforest fires are a big problem for the whole world.

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The Amazon Rainforest has been burning for weeks. Here’s why that matters.

Photo, posted August 21, 2019, courtesy of NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

California Fires And Precipitation

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Two things we have heard a lot about in recent years have been the persistent drought in California and the terrible wildfires the state has experienced.  Along the way, the state has had some pretty wet and snowy winters.  This past winter, the California snow pack has seen incredible levels building up, which is great news for the state’s farmers.  But does that also mean that the next year should see some relief from severe wildfires?

The answer appears to be no.  A new study from an international team that includes the University of Arizona has comprehensively looked at the amount of winter precipitation in California and the severity of the subsequent wildfire season. 

The position of the North Pacific jetstream over California is strongly linked to the amount of winter precipitation.  This has been true for hundreds of years and continues to be the case.

From 1600 to 1903, the linkage between winter precipitation and wildfire severity was also very strong.  But after 1904, that connection weakened.  As a result, fire suppression policies were instituted.  When fires arose, they were put out as quickly as possible.  The result over time is fuel buildup, making larger fires far more likely.

According to the new study, after 1977, the connection between winter precipitation and wildfire severity disappeared entirely.  There no longer appears to be any relationship between jet stream dynamics and fire.  The warming climate and the results of fire suppression dominate the potential for wildfire.  California’s wet winter of 2016-2017 provides a good example.  That winter was followed by many large fires in 2017.

So, this very wet winter in California does not imply that this should be a year without severe wildfires.

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Wildfire Risk in California No Longer Coupled to Winter Precipitation

Photo, posted July 26, 2018, courtesy of Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fire-Driven Thunderstorms

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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 21st 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.

Indonesian Deforestation

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Deforestation is defined as the intentional destruction of trees and other vegetation without reforesting or allowing the forest to regenerate itself. 

In Indonesia, industrial agriculture, primarily for the production of palm oil, is a major driver of deforestation.  But, according to researchers at Duke University, its impact has diminished  proportionately in recent years as other natural and human causes have emerged. Their peer-reviewed findings were recently published in the journal Environmental Research Letters.

According to the study’s lead author, large-scale plantations were responsible for more than half of Indonesia’s deforestation in the late 2000s, peaking between 2008-2010 when an average of 1.5 million acres of forest was lost annually.  The expansion of the massive plantations was responsible for 57% of the forest loss. Between 2014-2016, an average of more than 2 million acres of forest was lost annually, but plantation expansion only accounted for 25% of this figure.  While the overall rate of deforestation continued to grow, other factors were responsible for most of it.

Conversions of forests to grasslands rose sharply in 2015 and 2016 when El Nino caused severe droughts and forest fires. Small-scale farming, often overshadowed by industrial agriculture, was also found to play a bigger role, accounting for 25% of all forest loss. 

Indonesia has experienced some of the highest rates of deforestation.  Its forests absorb and store vast amounts of climate-warming carbon dioxide, help prevent erosion and flooding, and provide habitat to thousands of species.  Understanding the varied causes of Indonesian deforestation should help conservationists and policymakers better address the problem.

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Palm oil not the only driver of forest loss in Indonesia

Photo, posted March 26, 2018, courtesy of Achmad Rabin Taim via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Climate-Friendlier Coolant

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Recently, negotiators from more than 170 countries reached a legally binding accord in Kigali, Rwanda to cut the use of hydroflurocarbons, or HFCs, which are chemical coolants used in air conditioners and refrigerators.  HFCs are just a small percentage of the greenhouse gases in the atmosphere, but they are supercharged greenhouse gases that have 1,000 times the heat-trapping potency of carbon dioxide.

[Read more…] about A Climate-Friendlier Coolant

Snowpack Loss

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A recent study showed that this year the snowpack in California, which is suffering an ongoing drought as well as long-term warming, reached its lowest point in 500 years.   Snowmelt from the Sierra Nevada mountains fills reservoirs that provide a third of all of the drinking water for the state of California, as well as water used to fight fires and generate electricity.

[Read more…] about Snowpack Loss

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