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Wildfires and water quality

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Hotter and drier conditions driven by climate change are leading to an increasing number of wildfires in North America and around the world. The damage wildfires cause – to forests, homes, and communities – is well-known. But long after the flames are gone, the effects can linger, especially in rivers and streams, where water quality may suffer for years.

A new study by scientists at the CIRES institute at the University of Colorado Boulder analyzed more than 100,000 water samples from more than 500 sites across the Western U.S. and found that wildfires can degrade water quality for up to eight years after a fire. The research, which was recently published in the journal Nature Communications Earth & Environment, found elevated levels of organic carbon, nitrogen, phosphorus, sediment, and turbidity – the cloudiness of water – in basins affected by fire.

This large-scale analysis reveals watersheds take longer to recover from wildfires than previously thought, with widespread, long-lasting impacts often going undetected for years.

Organic carbon, phosphorus, and turbidity remain elevated for one to five years after a fire. Nitrogen and sediment levels stay notably high for up to eight years. Fire-driven impacts are worse in more forested areas.

Each watershed in the study responded differently depending on local conditions.  In some places, sediment levels surged to as much as 2,000 times normal levels, while others remained relatively unchanged.

The research team hopes its findings can help guide future planning efforts to improve wildfire resilience.

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Wildfires threaten water quality for years after they burn

Photo, posted April 6, 2017, courtesy of Bonnie Moreland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The human footprint on Earth

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The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it.  But the impact of human activities on our planet continues to grow.  Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it.  Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert.  Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly.  Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia.  Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise.  The effects of this on the planet are increasingly evident.  Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn.  The massive wildfires in and around Los Angeles have made major changes in the local landscape.  Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs.  Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high.   These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon levies for shipping

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The global shipping industry is responsible for 90 percent of world trade.  The ships crossing the world’s oceans emit nearly 3% of the global greenhouse gas emissions caused by human activity that are contributing to climate change.  Among the effects of climate change are sea level rise, which is threatening the very existence of small island nations.

One such nation is Tuvalu, which is a group of islands in the South Pacific.  Tuvalu has a total landmass of just 10 square miles, and sea level there is rising 1.5 times faster than the global average.  Predictions are that within 50 to 100 years, low-lying islands like those of Tuvalu could be fully submerged by the ocean.

Representatives from six Pacific Island states and a growing number of Caribbean nations known as the 6Pac+ Alliance are urgently calling upon the International Marine Organization to enact a mandatory universal levy of $150 per ton of shipping emissions from large commercial vessels. 

Most marine vessels typically run on highly polluting heavy fuel oil.  Burning really filthy fuel is the cheapest way to cross the oceans.  There are alternatives including entirely carbon-free technologies, but they will be expensive to implement and utilize.  The cost of shipping would undoubtedly go up and be especially felt by small island nations and in developing countries where most food is imported.

The idea behind putting a price on ships’ carbon emissions is to both provide a financial incentive for the shipping industry to reduce its emissions and provide revenue for countries that incur costs from dealing with rising seas.

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Pacific and Caribbean Island Nations Call for the First Universal Carbon Levy on International Shipping Emissions

Photo, posted November 23, 2006, courtesy of Stefan Lins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Generations Z and Alpha and climate change

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People’s views and level of concern about climate change tend to vary according to age, political affiliation, and other demographic categories.  But one clear trend is that young people are overwhelmingly concerned about climate change.  Given that they will ultimately suffer from its effects far more than older generations, this is not really surprising.

A new study investigated the views about climate change of 16,000 young Americans aged 16 to 25.  The study found that about 60% of respondents said they were either very or extremely worried when asked “How worried, if at all, are you about climate change and its impact on people and the planet?”  More than 85% said they experienced at least some level of climate anxiety.

There was similarity in responses across dramatically different geopolitical regions of the country.  Responses never differed by more than 25% across all surveyed populations.  Concern about climate change transcended political identification.  While the Republican group did have a lower level of concern, endorsement of climate issues was still above 50% no matter what group people identified with.

People from Generations Z and Alpha, those with fewer economic resources, people of color, and other vulnerable communities are experiencing the highest levels of climate distress. Research finds that 3% of Americans are experiencing clinically significant climate anxiety. 

The true number of people experiencing climate-triggered anxiety may be much higher as some people are hesitant or reluctant to even acknowledge that climate change is happening.  Some level of climate anxiety is undoubtedly beneficial for climate action.  People who are experiencing distress are the ones most likely to take action. 

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The Depths of Their Discontent: Young Americans Are Distraught Over Climate Change

Photo, posted April 23, 2022, courtesy of Mark Dixon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Megafires and orchard health

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The frequent and massive megafires in places like Canada and the American west have led to a lot of research on the impact of smoke on humans but there has been less study of the effects of smoke on plant health.  Researchers at the University of California, Davis have found that trees are just as vulnerable as humans are to the harmful effects of long-term exposure to smoke.

The Davis researchers studied almond, pistachio, and walnut trees at 467 orchard sites in California’s Central Valley from 2018 to 2022.  In 2022, so-called megafires burned more than 4.2 million acres in California, pouring ash and smoke into the sky.  The researchers had been studying how trees store carbohydrates to cope with heat and drought. 

With the onset of the fires, they saw an opportunity to study how smoke affects carbohydrate levels.  Trees use stored carbohydrates to sustain them through winter dormancy and spring growth.  Trees produce carbohydrates via photosynthesis and thick smoke blocks the amount of light reaching the trees.  Beyond that, there are other aspects of wildfire smoke, such as particulate matter and ozone that appear to affect photosynthesis.

The team found that the smoke not only reduced the amount of carbohydrates in trees but also caused losses that continued even after the fires were extinguished.  This led to nut yield decreases of 15% up to 50% in some orchards.  The researchers expected to see some impact on the trees during periods when smoke was really dense but were not expecting the smoke to have such a lingering effect and result in a significant drop in yield.

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Smoke From Megafires Puts Orchard Trees at Risk

Photo, posted October 1, 2008, courtesy of Suzi Rosenberg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and Antarctic meteorites

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Researchers from Switzerland and Belgium have investigated the effects of the warming climate on access to meteorites in Antarctica.  Meteorites are of great scientific interest because they provide unique information about the makeup of our solar system.  Of all the meteorites that people have found, 62.6% of them were found in Antarctica.

Why is this?  It is not because more meteorites land in Antarctica.  Statistically, they can land anywhere on earth.  Most end up in the ocean since the world’s oceans cover 70% of the planet. 

Meteorites in Antarctica are more visible because environmental conditions are favorable for their preservation and their visibility.  The arid and cold Antarctic environment helps to preserve meteorites and the lack of rocks and contrast with ice makes spotting meteorites much easier.  The flow of ice sheets tends to concentrate meteorites in so-called meteorite stranding zones where the dark colored space rocks can be easily detected.

There are an estimated 300,000 to 800,000 meteorites in Antarctica.  When meteorites warm up, they can transfer heat to the ice, which locally melts.  Eventually, the meteorites sink beneath the surface.  A recent study using satellite imagery, climate model projections, and AI predicts that for every tenth of a degree of increase in global air temperature, an average of 9,000 meteorites in Antarctica will disappear from the surface and will no longer be able to be found. 

The study estimates that a quarter of Antarctic meteorites will be lost to glacial melt by 2050.  If warming continues to accelerate, closer to three-quarters of the meteorites on the continent will be lost. 

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Climate change threatens Antarctic meteorites

Photo, posted April 21, 2005, courtesy of Kevin Walsh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How to make cities cooler

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In cities, the air, surface, and soil temperatures are almost always warmer than in rural areas. This is known as the urban heat island effect.  Urban heat islands occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat.

Urban planners around the world have been researching ways to reduce the effects of heat in cities.  For example, trees, green roofs, and vegetation can help reduce urban heat island effects by shading building surfaces, deflecting radiation from the sun, and releasing moisture into the atmosphere.

A new study led by researchers from the University of Surrey in the U.K. has analyzed how well various green spaces and waterways are able to cool down cities.  The study, which was recently published in the journal The Innovation, found that wetlands, parks, and even botanical gardens are among the best ways to keep cities cool.   

In fact, the researchers found that botanical gardens can cool city air by a whopping 9°F during heatwaves on average.  Wetlands can cool city air by 8.5°F on average, followed by rain gardens at 8.1°F, green walls at 7.4°F, street trees at 6.8°F, city farms at 6.3°F, city parks at 5.8°F, and reservoirs and playgrounds at 5.2°F. 

The researchers also found that cities can unlock even greater benefits by connecting green spaces into green corridors.  Greening projects can also help remove carbon emissions and prevent flooding.

The research team hopes its findings will help urban planners design more resilient cities. 

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Wetlands, parks and even botanical gardens among the best ways to cool cities during heatwaves

Photo, posted April 25, 2022, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfires and air quality

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The wildfires last summer in parts of the U.S. and Canada fouled the air over much of the country.  Air quality in many places was dangerous for human health.  And such fires are becoming more numerous and more intense.

A new study by the University of Iowa has assessed the effects of two decades of wildfires on air quality and human health in the continental U.S.

From 2000 to 2020, air quality in the western U.S. has gotten worse as a result of the numerous fires in that region.  More generally, all those fires have undermined the success of federal efforts to improve air quality, primarily through the reductions in automobile emissions.

American air had been getting cleaner and clearer as a result of EPA regulations on vehicle emissions, but the surge in wildfires has limited and, in some cases, erased these air quality gains.  Twenty years of efforts by the EPA to make our air cleaner have been lost in fire-prone areas and in many downwind areas.

The Iowa study looked at the concentration of black carbon, a fine-particle air pollutant from fires linked to respiratory and heart disease.  In the western U.S., black carbon concentrations have risen 86% on an annual basis.

Fires have also affected the air in the Midwest, although not to the same degree as in the west.  The eastern U.S. had no major declines in air quality during the 2000-2020 time period.  Given the episodes of smoke from Canadian wildfires experienced by the east coast this past summer – as far south as Florida – even the air in that part of the country is suffering from the spread of wildfires.

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Wildfires have erased two decades’ worth of air quality gains in western US

Photo, posted June 8, 2023, courtesy of Anthony Quintano via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Geoengineering could create winners and losers

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Geoengineering – deliberate interventions to alter the climate and curb climate change – is a controversial topic, to say the least.  Once practically considered taboo even to discuss, there in increasing interest in at least exploring various ideas about how to halt or reverse climate change through direct actions that impact global temperatures.

Putting aside the very real concerns about the risks and dangers associated with such action, there is also the issue that climate interventions may create dramatically different effects across the globe, benefitting some areas and adversely affecting others.

A recent study by scientists at Rutgers University tackled this very issue.  Published in the journal Nature Food, it described the results of computer models simulating the impacts of stratospheric aerosol intervention (SAI), which is spraying sulfur dioxide into the stratosphere, where it would partially shield the Earth from the Sun, lowering temperatures.

The study looked at 11 different SAI scenarios and found that none of them benefitted everyone.  Uncontrolled global warming favors crop production in cold, high-latitude areas such as Canada, Russia, Scandinavia, and our northern border states.  Moderate amounts of SAI favors food production in the mid-latitudes (such as in the US and Europe.)  Large amounts of intervention favors agricultural production in the tropics. 

Even if geoengineering might not have dire consequences – which is by no means certain – it would create winners and losers.  Nations may have different ideas of what constitutes an optimal global temperature.  So, who gets to decide where to set the global thermostat?  The prospects for conflict loom large. 

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Climate Intervention Technologies May Create Winners and Losers in World Food Supply

Photo, posted November 18, 2021, courtesy of Conall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Cost Of Invasive Species | Earth Wise

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According to a new report published by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services for the United Nations, invasive species introduced to new ecosystems around the world are causing more than $423 billion in estimated losses to the global economy every year.  These economic costs are incurred by harming nature, damaging food systems, and threatening human health.

According to the report, these costs have at least quadrupled every decade since 1970 and the estimates are actually conservative because it’s difficult to account for all of the effects of invasive species.

The report estimates that humans have intentionally or unintentionally introduced more than 37,000 species to places outside their natural ranges.  More than 3,500 of them are considered invasive because they are harmful to their new ecosystems.  Invasive nonnative species were a major factor in 60% of known extinctions of plants and animals.

Some species are relocated deliberately by the wildlife trade and international shipping.  Other plants and animals end up hitching a ride with ordinary travelers as they move about by car, boat, plane, or train. 

Invasions can damage human health.  Mosquitos that transmit diseases like malaria, dengue fever, and the Zika virus have become invasive around the world. The wildfires in Hawaii this summer were fueled by invasive nonnative grasses in a warming climate. 

Nearly every country in the world has agreed to participate in a sweeping agreement to preserve biodiversity and reduce invasive species.  It is an essential global goal.

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Invasive Species Are Costing the Global Economy Billions, Study Finds

Photo, posted June 2, 2022, courtesy of Sam Stukel (USFWS) via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouse Gas Emissions Are Still Increasing | Earth Wise

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Recent research has found that the level of greenhouse gases emitted by human activity has reached an all-time high level of nearly 60 billion tons a year.  Despite increasing public attention, policy measures, and adoption of green technologies, the pace at which these changes have been taking place has simply not kept up with the ongoing burning of fossil fuels by increasingly industrialized societies.  The rate at which greenhouse gas emissions has increased over time has indeed slowed, but emissions need to start decreasing and as soon and as much as possible.

Human-induced warming has reached a ten-year average from 2013-2022 of 1.14 degrees Celsius above pre-industrial levels, up from a 1.07 degrees average between 2010-2019. 

Scientists have calculated a carbon budget that describes how much more carbon dioxide can be emitted before global warming exceeds the threshold of 1.5 degrees Celsius that is widely predicted to lead to potentially catastrophic changes to the climate.  In 2020, the Intergovernmental Panel on Climate Change calculated that the remaining carbon budget was about 500 billion tons of carbon dioxide.  Over the past three years, nearly half of that carbon budget has already been exhausted by the continuing onslaught of carbon emissions.

Researchers describe their study as a timely wake-up call that the pace and scale of climate action to date has been insufficient and that we need to change policy and approaches in light of the latest evidence about the state of the climate system.  Time is no longer on our side in trying to stave off the worst effects of climate change.

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Greenhouse gas emissions at ‘an all-time high’, warn scientists

Photo, posted September 18, 2015, courtesy of In Hiatus via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfire Smoke And Global Weather | Earth Wise

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In 2019 and 2020, wildfires burned 72,000 square miles in Australia, roughly the same area as the entire country of Syria. During the nine months when the fires raged, persistent and widespread plumes of smoke filled the atmosphere.

These aerosols brightened a vast area of clouds above the subtropical Pacific Ocean.  Beneath these clouds, the surface of the ocean and the atmosphere cooled.  The effect of this was an unexpected and long-lasting cool phase of the Pacific’s La Niña-El Niño cycle.

A new modeling study by the National Center for Atmospheric Research in Boulder, Colorado quantified the extent to which aerosols from the Australian wildfires made clouds over the tropical Pacific reflect more sunlight back towards space.  The resultant cooling shifted the cloud and rain belt known as the Intertropical Convergence Zone northward.  These effects may have helped trigger the unusual three-year-long La Niña, which lasted from late 2019 through 2022.

The impacts of that La Niña included intensifying drought and famine in Eastern Africa and priming the Atlantic Ocean for hurricanes.  2020 was the most active tropical storm season on record, with 31 storm systems, including 11 that made landfall in the U.S.

The study highlights widespread multi-year climate impacts caused by an unprecedented wildfire season.  The wildfires set off a chain of events that influenced weather far from where the fires occurred.  In the future, climate experts will need to include the potential effects of wildfires in their forecasts.

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How Wildfire Smoke from Australia Affected Climate Events Around the World

Photo, posted December 19, 2019, courtesy of Simon Rumi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ocean-based Climate Intervention And Deep-sea Ecosystems | Earth Wise

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Deep-sea ecosystems cover more than 40% of the Earth.  These regions are some of the least well-known and understood areas of our planet but are home to numerous ecosystems.  The deep seas are already directly exposed to the effects of human-induced climate change but could potentially be greatly threatened by efforts to artificially counteract climate change.

A class of geoengineering solutions called ocean-based climate interventions are increasingly being claimed as promising ways to mitigate climate change.  Such interventions would remove carbon dioxide from the atmosphere and sequester it in the deep sea.  There is very little known about the impact of such efforts on ocean biogeochemistry and the biodiversity of ocean ecosystems.

One approach is direct CO2 injection into the deep ocean, which would sequester large amounts of it and reduce the concentration in the atmosphere.  However, too much carbon dioxide in the water is called hypercapnia, which can have serious consequences on marine life.

Other approaches include ocean fertilization – which is enhancing phytoplankton production at the surface, leading to their eventual deposition on the deep-sea floor – and crop waste deposition – which is deep-sea disposal of terrestrial crop waste. 

A multinational study led by the Scripps Institution of Oceanography warns that there needs to be much more research and governance before any such interventions ever take place.  The deep sea faces unprecedented threats from industrial fisheries, pollution, warming, deoxygenation, acidification, and other climate-related problems.  Ocean-based climate intervention represents yet another serious threat to the functioning of these essential ecosystems.

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HKU Marine Scientist contributes to research assessing the potential risks of ocean-based climate intervention technologies on deep-sea ecosystems

Photo, posted January 6, 2010, courtesy of Emrys Roberts via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Humanity Weighs On The World | Earth Wise

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There are countless ways in which humankind has had disproportionate effects on our planet and most of those effects have been negative.  A recent study led by the Weizmann Institute of Science in Israel looked at the total combined weight of various groups of mammals on Earth.  The results are that human beings and our domesticated mammals are the overwhelming majority of the total mass of mammals.

We think of large land mammals – elephants, bears, bison, wildebeests, and so on – as adding up to a massive amount of animal matter.  The study determined that all wild land mammals put together add up to about 22 million metric tons. Wild marine mammals – such as dolphins and whales – add up to about 40 million tons in total.  These sound like pretty big numbers until we look at the human and human-created side of the equation.

The study found that humans weigh about 390 million metric tons, while domesticated mammals – like sheep, cows, and pigs as well as dogs and cats – weigh about 630 million metric tons combined.

All told, wild mammals account for only 6% of all mammals by weight.   People and their domesticated animals make up the other 94%.  This enormous imbalance is an indication of how profoundly humans have reshaped life on Earth.  House cats total twice the weight of African elephants and pigs add up to twice the weight of all wild land animals combined.

The conclusion to draw from the big picture here is that wild animals on Earth are not doing very well.  We already knew this from many other perspectives, but this census by weight presents a stark picture of the extent to which we have taken over the planet and its ecosystems.

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Total Weight of Wild Land Mammals Less Than One-Tenth Weight of All Humans

Photo, posted December 27, 2006, courtesy of Nigel Hoult via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Beavers As Climate Change Fighters | Earth Wise

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California is fighting the effects of climate change on multiple fronts.  The state has been grappling with relentless drought, record heat waves, and persistent wildfires.  The California Department of Fish and Wildlife is enlisting the help of beavers in its battle against climate change.

The state has created a beaver restoration unit charged with developing methods for nature-based restoration solutions involving beavers as well as artificial beaver dams. The agency plans to spend at least $3 million over the next two years to oversee a restoration program for the North American beaver.

A 2020 study showed that beaver-dammed corridors were relatively unharmed by wildfires compared with other areas that lacked beaver damming.  The study highlighted the differences between two adjacent corridors – one without a beaver population with a landscape scarred by a recent wildfire and another with beavers that remained a lush wetland after a fire.   The differences in burn severity, air temperature, humidity, and soil moisture between the beaver complex and the adjacent landscape were huge. 

From the 1920s through the 1950s, California actively exported beavers to other parts of the state and country so they could build dams in eroded areas where beaver dams could help evenly distribute water.  Now, the state wants to reintroduce beavers into watersheds where they once flourished.

The Department of Fish and Wildlife’s proposal to the California Legislature called beavers an important keystone species that can be used to combat climate change.   The state has spent enormous amounts of money on wildfire measures with minimal results.  Now they are going to see if beavers can make a difference.

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California says the beaver can be superhero in fighting climate change

Photo, posted September 19, 2021, courtesy of Larry Lamsa via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Antarctic Heatwave | Earth Wise

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The Concordia Research station atop Dome C on the Antarctic Plateau is generally considered to be the coldest place on earth.  In mid-March, the normal high temperature for the day is around -56 degrees Fahrenheit.  But on March 18, the high for the day was 11.3 degrees, nearly 70 degrees warmer than normal.

The World Meteorological Organization doesn’t formally track the metric of largest temperature excess above normal, but if it did, this would probably have set a world record.  Consider a place like Washington, DC.  Its normal high temperature on March 18 is 61 degrees.   Imagine if it got up to 131 degrees! 

The 11-degree reading at the Concordia Research Station was not only the record for the month of March.  It was actually the record for any month.

The Russian Vostok research station, which is another candidate for being the coldest place on earth based on its average high temperature, also saw some record high temperatures.  Vostok reported a high temperature of zero degrees Fahrenheit, which is 63 degrees above its average for the date.  It broke the station’s previous record by almost 27 degrees.

This record warming was the result of a unique combination of meteorological events that included a moist inflow of an atmospheric river as well as a rare infusion of hot air into the Antarctic plateau.  The arrival of the moisture in the atmospheric river trapped the hot air, allowing temperatures to shoot up.

The extreme warmth in Antarctica raises concerns about the long-term effects on the ice there.  A single short heatwave is not going to have a major effect, but if such events become more common, it could be real problem.

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Extraordinary Antarctica heatwave, 70 degrees above normal, would likely set a world record

Photo, posted October 15, 2016, courtesy of NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Understanding Geoengineering | Earth Wise

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The most recent report from the UN Intergovernmental Panel on Climate change includes discussion of a number of extreme and untested solutions to the climate crisis.  Among these are solar geoengineering – modifying clouds or spraying tiny reflective particles into the upper atmosphere in order to block some of the sun’s light and thereby cool the planet.  The underlying principles are relatively straightforward.

There have been various models that predict the extent to which solar geoengineering would lower the earth’s average temperature.  What hasn’t been modeled to any real extent is what other effects it would have.

The new report discusses the results of models that predict how temperatures would vary at different latitudes and how geoengineering would affect rainfall and snowfall.  According to the models, releasing sulfate aerosols into the upper atmosphere to block sunlight would lower average precipitation.  But every region would be affected differently.  Some regions would gain in an artificially cooler world, but others might, for example, suffer by no longer having suitable conditions to grow crops.

The drop in temperature would allow the planet’s carbon sinks (plants, soils, and oceans) to take up more carbon dioxide from the atmosphere.  However, as long as people continue to pollute, carbon dioxide would continue to make the oceans more acidic, causing significant harm to marine ecosystems.  Furthermore, solar geoengineering would have to be an ongoing process that would go on indefinitely and if it were to suddenly stop, it would lead to rapid warming.

The more we learn about geoengineering, the more it becomes clear that there would be many side effects as well as serious moral, political, and practical issues.  Society has to consider if all these things represent too much danger to allow us to seriously consider such a strategy.

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In the New UN Climate Report, a Better Understanding of Solar Geoengineering

Photo, posted September 9, 2012, courtesy of Kelly Nighan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas And Wastewater Leakage | Earth Wise

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Global mean sea level has risen nearly 9 inches since 1880, with over two inches of that over just the last 25 years.  The rising water level is primarily due to two factors:  additional water in the oceans coming from melting glaciers and ice sheets; and the thermal expansion of seawater as it warms.  Climate models estimate that over the course of the century, global sea levels will rise at least a foot even if efforts to reduce greenhouse gas emissions are quite successful and, in the worst case, levels could rise as much as 8 feet.

Faced with this situation, the greatest concerns are, initially, increasing amounts of coastal flooding and erosion and, as things get worse, inundation of coastal regions making many places uninhabitable and creating millions of climate refugees.

Recently, computer modeling studies have focused on an additional imminent problem:  the flooding of coastal wastewater infrastructure, which includes sewer lines and cesspools.

A new study by the University of Hawaii at Manoa is the first to provide direct evidence that tidally driven groundwater inundation of wastewater infrastructure is already occurring in urban Honolulu.  The study shows that higher ocean water levels are leading to wastewater entering storm drains and the coastal ocean.  The result is degradation of coastal water quality and ecological health.

The researchers used chemical tracers to detect groundwater discharge and wastewater present at multiple low-lying areas during spring tides.  During high tides, storm drains become channels for untreated wastewater to flood streets and sidewalks. 

People tend to think of sea-level rise as a future problem, but there are already serious effects going on today that are only going to get worse.

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Sea-level rise drives wastewater leakage to coastal waters

Photo, posted August 23, 2011, courtesy of Eric Tessmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tree-Planting Is Not Necessarily A Good Thing | Earth Wise

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There is no question that forests have a major role in efforts to combat climate change as well as to slow biodiversity loss.   As a result, tree-planting on a massive scale has gained traction as a strategy and there have been major commitments made to plant billions of trees around the world.

A new study at Stanford University has rigorously analyzed the potential effects of these efforts and has found some significant problems.  For example, the Bonn Challenge, which seeks to restore an area of forest more than eight times the size of California over the next 10 years, has 80% of its commitments in the form of  planting monoculture tree plantations or a limited mix of trees that produce fruit and rubber, rather than restoring natural forests.   The problem is that plantations have significantly less potential for carbon sequestration, habitat creation, and erosion control than natural forests.  The potential benefits of the planting dwindle further if planted trees replace natural flora – forests, grasslands, or savannahs – which are ecosystems that have evolved to support local biodiversity.

The study looked at previous policies that created subsidies for planting trees.  Chile’s Decree Law, in effect from 1974 to 2012, has served as a model for similar policies in a number of countries.  Those subsidies further reduced native forest cover by encouraging the establishment of plantations in places where forests might have naturally regenerated.  The subsidies expanded the area covered by trees, but decreased the area of native forests.

The study recommends that nations should design and enforce their forest subsidy policies to avoid undesirable ecological impacts and actually promote the recovery of carbon- and biodiversity-rich ecosystems.

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Poorly designed tree-planting campaigns could do more harm than good, according to Stanford researcher and others

Photo, posted April 28, 2016, courtesy of the U.S. Department of State via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Planting Trees and Climate Change | Earth Wise

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Forests are among the most important natural carbon sinks.  Trees remove carbon from the air and store it in their trunks, branches, and leaves, and transfer part of it into the soil.  But in some regions, these natural carbon sinks are starting to weaken due to deforestation, forest degradation, and the impacts of climate change.  This problem has led some climate mitigation projects to focus on increasing the overall number of trees on the planet. 

But, according to a paper recently published in the journal Science, “we can’t plant our way out of climate change.”  That’s the simple message from Restoration Ecologist Karen Holl and University of São Paulo Professor Pedro Brancalion to anyone who thinks planting one trillion trees will reverse the effects of climate change.  They say planting more trees is only one piece of the puzzle.  Any initiatives like 1t.org or the Trillion Tree Campaign must be done carefully and be accompanied by commitments to long-term management.

Tree plantings can provide many environmental benefits, including improving water quality, biodiversity, and increasing shade.  But trees can sometimes have undesirable impacts, such as harming native species and ecosystems or reducing water availability, depending on where and how the trees are planted.

The authors suggest four principles that should guide forest enhancement initiatives: reduce forest clearing and degradation, balance ecological and social goals, view tree plantings as one part of a multifaceted solution, and plan, coordinate and monitor the work. 

While tree plantings can clearly be part of the solution, slowing the pace of climate change requires a comprehensive approach that must start with burning less fossil fuels.

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Web Links

Challenges in tree-planting programs

Planting trees is no panacea for climate change

Photo, posted December 1, 2019, courtesy of Akuppa John Wigham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)