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Managing Pests With Cover Crops | Earth Wise

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The use of pesticides in global agriculture brings with it many problems including the killing of non-target, beneficial species as well as reversing pest-management gains from the use of conservation agriculture methods.

In a newly published study by researchers at Penn State University, the use of plant cover, such as cover crops, was shown to potentially be more effective at reducing pest density and crop damage than the application of insecticides without the downsides.  Cover crops reduce insect pest outbreaks by increasing pest predator abundance.

Cover crops are plantings that are primarily used to slow erosion, improve soil health, enhance water availability, smother weeds, and help control pests and diseases.  Typical cover crops include mustard, alfalfa, rye, clovers, buckwheat, and winter peas.  Most cover crops are fairly inexpensive to plant.

Plant cover can provide habitat for populations of natural enemies of pests.  Winter cover crops can harbor pest predator populations outside of the growing season of the cash crop.  When the cover crop is killed off to allow the growth of the cash crop, residues of the cover crop remain on the soil during the growing season, so they still enhance the habitat for pest predators.

Conservation agriculture includes methods like cover crops, no-till planting, and crop rotation.  The use of cover crops constitutes a form of preventive pest management that is an alternative to planting seeds treated with systemic insecticides to control early-season pests.  There is also the possibility for integrated pest managements, which is an approach in which insecticides are applied but only when pest numbers exceed economic thresholds despite the use of nonchemical tactics.

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Cover crops more effective than insecticides for managing pests, study suggests

Photo, posted August 8, 2011, courtesy of USDA NRCS Montana via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Getting Rid Of Single-Use Plastics | Earth Wise

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Single-use plastics are used only once before they are recycled – or more likely – simply thrown away.  These are things like plastic bags, straws, coffee stirrers, soda and water bottles, and most food packaging.  They are primarily made from fossil fuel-based chemicals.

Since the 1950s, over 9 billion tons of plastics have been produced, and half of that has been in the past 15 years.  There are uses for plastic that are not only reasonable, but are even important, such as for surgical gloves.  But for the most part, single-use plastic is the poster child of our throwaway culture that is bad for the environment, for wildlife, and even for human health.

Many cities, states, and even countries are moving toward greatly limiting or outright banning single-use plastics.  A recent global survey indicates that the great majority of people around the world are with the program.

According to a 28-country survey from marketing firm Ipsos and the activist group Plastic Free July, three out of four people around the world agree with a ban on single-use plastics.  The poll of more than 20,000 people showed that in Latin America, China, and India, more than 80% agree that a ban should happen as soon as possible.  Unfortunately, Canada, the United States, and Japan were the least supportive countries.  In particular, only 40% of Japanese respondents favored a ban.

Ninety percent of respondents globally support an international treaty to combat plastic pollution and eighty percent said they personally want to buy products with as little plastic packaging as possible.  Unfortunately, people in wealthy countries, which produce the most plastic waste, are less likely to support a ban.  Those countries typically export their waste to the developing world.

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Three in Four People Worldwide Support a Ban on Single-Use Plastics

Photo, posted April 13, 2006, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Is It Really Getting Warmer? | Earth Wise

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The primary indicator of global climate change is the Global Mean Surface Temperature of the Earth and the world’s nations are trying to keep its increase below 1.5 degrees Celsius over the pre-industrial level.   That rise in temperature is called the Global Surface Temperature Anomaly and it actually reached an all-time high in 2016 at 1.02 degrees before going back down.

At this point, you might be saying, “hold on there…  it hasn’t gotten larger over the past 5 years?”  What’s going on?

The global climate is pretty complicated and there are many things that influence it.  One of the most significant factors is the El Niño Southern Oscillation or, more familiarly, the El Niño.  The El Niño is a periodic and irregular variation in the sea surface temperature of the tropical eastern Pacific Ocean driven by persistent westerly winds.  When an El Niño is happening, currents move to the west coast of South America and warm the tropics and subtropics.  This causes a spike in the global mean temperature.  There was a strong El Niño in 2016.

On the other hand, when easterly winds dominate to form a La Niña, cool water comes up from the depths of the Pacific and cools the atmosphere.  In 2017 and 2018, there was a fairly strong La Niña, lowering the global mean temperature.  2020 had no El Niño or La Niña, and the global temperature went back up to its previous peak.  Last year, there was again a La Niña and the temperature dipped again.

The global mean surface temperature has been rising in the industrial era, but it also fluctuates with the complicated dynamics of the Pacific Ocean.

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Why Isn’t It Getting Warmer?

Photo, posted February 12, 2016, courtesy of Amit Patel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

January Climate Report Card | Earth Wise

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January was the sixth-warmest January in the 143 years of global climate record keeping.  The global land and ocean surface temperature was 1.6 degrees Fahrenheit above the 20th century average.

Meanwhile, the United States had its coolest January since 2014, although the month still ranked nearly a degree above the long-term average across the nation.  This January was also the driest January in eight years and was one of the top- 15 driest Januarys on record.  That being said, there was the so-called Bomb Cyclone late in the month that dumped 1-2 feet of snow and brought blizzard conditions along the eastern seaboard and set a one-day snowfall record in Boston.

Global conditions and regional and local conditions can be very different.  In the big picture, January was the 46th consecutive January and the 445th consecutive month with temperatures above the 20th century average.

And while the US had a fairly cool January, South America saw its second-warmest January on record, Asia had its fourth warmest, and Oceania had its seventh warmest.

Apart from temperatures, Antarctic sea ice coverage was the second smallest January extent in 44 years.  Arctic ice was 208,000 square miles below the 1981-2010 average, although it was the largest since 2009.

Even as the global climate warms, local and regional climate conditions will continue to have unique and variable characteristics over the course of time.  Every time there’s a bout of cold weather, it isn’t time to stop being concerned about climate change.

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January 2022 was Earth’s 6th warmest on record

Photo, posted January 6, 2013, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tourism And Invasive Species | Earth Wise

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Tourism has experienced exponential growth during the past 70 years.  In 1950, there were 25 million international tourist arrivals.  By 1990, it had ballooned to 435 million.  Between 1990 and 2018, the numbers more than tripled reaching more than 1.4 billion.  And by 2030, the number of international tourist arrivals is expected to reach 1.8 billion.

Tourism is vital to the success of many economies around the world.  Tourism can boost revenue, provide jobs, develop infrastructure, protect wildlife, and help preserve heritage sites and cultures.  But there can also be many downsides to tourism, one of which is that it can contribute to the introduction and spread of invasive species.  Non-native organisms can cause all sorts of social, environmental, and economic damage.   

Tourists help spread invasive organisms far and wide.  These organisms hitch rides in their luggage and on their shoes and clothing.  A 2011 study in New Zealand found that for every gram of soil on the shoes of in-bound international passengers, there were 2.5 plant seeds, 41 roundworms, 0.004 insects and mites, and many microorganisms. 

A new study by researchers from the University of Melbourne in Australia and AgResearch New Zealand examined to what degree tourism plays a role in the spread of invasive species.  According to the study, which was recently published in the journal NeoBiota, the research team found that the number of nights spent in hotels significantly correlated to the incursion of invasive species during that period.

Creating effective mechanisms to prevent the introduction of invasive species in the first place is the best way to prevent this problem. 

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Unwelcome guests: International tourism and travel can be a pathway for introducing invasive species

Number of tourist arrivals

Photo, posted March 27, 2005, courtesy of John via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Crops Threatened With Extinction | Earth Wise

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Crop variety and diversity are critically important for global food security as well as for the livelihoods of millions of people.  This diversity entails both the different species of food crops as well as the so-called farmer varieties of crops that in many cases have been cultivated and safeguarded for millennia.

It is well-known that many of these crops and varieties have been rapidly disappearing, but data has been scarce on just how many have been lost, how many we are losing, and which ones are the most threatened going forward.

A new study utilizes a methodology known as the Varietal Threat Index, which was developed by the Alliance of Bioversity International and CIAT, the International Center for Tropical Agriculture.  The study assessed about 600 farmers from seven Indian states, covering five different agroecological areas.  The farmers were selected based on their knowledge of crops and varieties across the 17 study sites.

The farmers listed the crops and varieties grown in their households, noted their uses, and indicated their spread and abundance, including information on varieties grown during the previous ten years which were no longer grown.

The results of the study showed that while there is a significant diversity of landraces – which are local varieties of species developed over time – more than 50% are threatened.  The trend is that crops and varieties mostly used for consumption are most often under threat, whereas varieties with multiple uses are less likely to be threatened.

Studies of this type can aid the development of targets and indicators to monitor the global status of plant genetic resources for food and agriculture and help inform urgent priority conservation actions.

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More than half of surveyed crop varieties are under threat of extinction, according to study in India

Photo, posted February 21, 2014, courtesy of Atibordee Kongprepan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Deadly Urban Heat On The Rise | Earth Wise

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According to a new study by the Columbia Climate School, exposure to deadly urban heat has tripled since the 1980s.  The increase is the combined result of both rising global temperatures and booming urban population growth.

The study looked at more than 13,000 cities worldwide and found that incidents of extreme heat and humidity have increased dramatically.   It defined extreme heat as 30 degrees Celsius on the wet-bulb temperature scale that takes into account the effect of high humidity.  In 1983, there were 40 billion person-days under such conditions.  By 2016, the number was 119 billion.  More specifically, in 2016 1.7 billion people were subjected to such conditions on multiple days.

Sheer urban population growth accounted for two-thirds of the increase, while actual warming contributed a third.  Over recent decades, hundreds of millions of people have moved from rural areas to cities, which now hold more than half the world’s population.  And because of the urban heat island effect, temperatures in cities are generally higher than in the countryside.

In the United States, about 40 sizable cities have seen rapidly growing exposure to extreme heat, mainly clustered in Texas and the Gulf Coast.  Globally, nearly a quarter of the world’s population is affected by the increased incidence of extreme temperatures.

A study last year showed that combinations of heat and humidity literally beyond the limits of outdoor human survival have been popping up around the world.  A wet-bulb temperature reading of 30 – equivalent to 106 degrees Fahrenheit on the “real feel” heat index – is the point at which even most healthy people find it hard to function outside for long, and the unhealthy might become very ill or even die.

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Exposure to Deadly Urban Heat Worldwide Has Tripled in Recent Decades, Says Study

Photo, posted March 5, 2007, courtesy of Michael Phillips via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coral Reefs And Ecosystem Services

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A new study led by the University of British Columbia provides the first comprehensive look at what climate change, overfishing, and habitat destruction of coral reefs mean for their ecosystem services.  For humans, this means how the global decline in coral reefs has affected their ability to provide essential benefits including food, livelihoods, and protection from storms.

The study found that global coverage of living corals has declined by about half since the 1950s and the diversity of reef species has declined by more than 60%.  So, it is no surprise that there has been a significant loss in the ability of reefs to provide ecosystem services.

The study analyzed data from coral reef surveys around the world, fisheries catches, indigenous consumption, and more.  Apart from the declines in reef coverage and biodiversity, the study found that fish catches on coral reefs peaked in 2002 and has steadily declined since then, despite increased fishing efforts.

The findings of the study led the researchers to conclude that continued degradation of coral reefs in the years to come threaten the well-being and sustainable development of millions of people in communities on the coast that depend on coral reefs.  Fish and fisheries provide essential nutrients in places with few alternative sources of nutrition.  Coral reef biodiversity and fisheries have added importance for indigenous communities, where important cultural relationships exist with reefs.

The study’s authors say that the results are a call to action.  The level of destruction happening all over the world’s coral reefs is threatening people’s culture, their daily food, and their history.  It is not just an environmental issue; it is a human rights issue.

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Photo, posted September 22, 2010, courtesy of David Burdick / NOAA Photo Library via Flickr.

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Carbon From 25 Cities | Earth Wise

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There are roughly 10,000 cities in the world, defined as places with at least 50,000 inhabitants with a sufficient population density.  Roughly half the world’s population lives in cities.

Urban carbon emissions are one of the world’s biggest problems with respect to the climate.  A new study has determined that just 25 cities globally are responsible for 52% of urban greenhouse gas emissions.

The study gathered data on greenhouse gas emissions in 167 cities in 53 countries.  The results were that megacities in Asia, such as Shanghai and Tokyo, were among the biggest total emitters, and that major cities in Europe, the US, and Australia tended to have larger per capita emissions.  Several Chinese cities, however, matched levels seen in developed countries.  Researchers tracked emissions over time in 42 of the cities studied.  Some cities saw declining emissions in the period between 2005 and 2016.  These included Oslo, Houston, Seattle, and Bogota.  Others saw large increases, including Rio de Janeiro, Johannesburg, and Venice.

The largest sources of emissions are power generation, industry, and transportation.  In a third of the cities, road transportation alone accounted for over 30% of emissions.  (Railways, waterways, and aviation combined only accounted for less than 15% of total emissions).

Half of the world’s population lives in cities, but cities are responsible for more than 70% of greenhouse gas emissions.  Thus, cities have a big responsibility for the decarbonization of the global economy.  Of the 167 cities in the study, 113 have set emission-reduction targets.  But as the study shows, cities have much more work to do to meet the goals of the Paris Climate Agreement.

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Two Dozen Large Cities Produce 52 Percent of Urban Carbon Emissions

Photo, posted December 1, 2017, courtesy of Hector Galbis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Kenya’s Tana River Basin | Earth Wise

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The Tana River is the longest river and most important waterway in Kenya.  It flows 620 miles from its headwaters in the Abderdare mountain range and Mount Kenya to the Indian Ocean.  The Tana River produces approximately half of the country’s electricity, and supplies Nairobi, the capital of Kenya, with 80% of its water.   

According to the United Nations Environment Programme, eight million people live along the Tana River, where coffee, tea, corn and other crops are grown for export, and fishing and cattle grazing help produce food for large portions of the country’s population. 

But the long-term ability of the river to provide these and other essential services is increasingly under threat due to many factors, including pollution, soil erosion, deforestation, and poor land use practices.   

Climate change is also complicating matters.  According to new research from the University of East Anglia, many species within the Tana River Basin will be unable to survive if global temperatures continue to rise at the current pace.  However, the study, which was recently published in the journal PLOS ONE, also found that many of these species could be saved if the world could meet the climate goals of the Paris Agreement. 

Globally, climate and land use changes are the two biggest threats to biodiversity.  According to researchers, 36% of the Tana River Basin has already been converted to agriculture. 

The research team says stronger commitments on climate change are needed from global leaders.  The climate and biodiversity crises can only be solved with urgent action to reduce global greenhouse gas emissions. 

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The impact of climate change on Kenya’s Tana river basin

Economics of Ecosystem Services of the Tana River Basin

Photo, posted August 19, 2010, courtesy of Luigi Guarino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Better Ways To Make Bioplastics | Earth Wise

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The world produces over 300 million tons of plastics each year, mostly produced from petroleum.  The environmental consequences are substantial and there is a critical need to replace as much of that plastic production with biodegradable plastics as possible.  Thus, there is global research aimed at making bioplastics more economical and as environmentally friendly as possible.

Researchers at Texas A&M University have developed an improved approach for making bioplastics from corn stubble, grasses, and mesquite agricultural production.  Apart from the obvious environmental benefits of having biodegradable plastics, producing bioplastics from common agricultural waste would create new revenue streams for farmers as well as the people who transport harvested feedstock and byproduct crops to refinery operations.

The key to bioplastic production is the efficient extraction and use of lignin, the organic polymer that is the primary structural support material in most plants.  The new research takes five conventional pretreatment technologies for plant materials and modifies them to produce both biofuel and plastics together at a lower cost.  The new method is called “plug-in preconditioning processes of lignin” and it can be directly and economically added into current biorefineries.  The process is designed to integrate dissolving, conditioning, and fermenting lignin, extracting energy from it and making it easily adaptable to biorefinery designs.

The so-called bioeconomy currently supports some 286,000 jobs.  Innovation is the key to achieving more widespread use of biodegradable plastic.  With improved economics of so-called lignocellulosic biorefineries, there can be new avenues to use agricultural waste to produce biodegradable plastics.

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‘Plugging in’ to produce environmentally friendly bioplastics

Photo, posted November 5, 2015, courtesy of Kathryn Faith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Have We Reached Peak Internal Combustion Engine? | Earth Wise

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According to new analysis from Bloomberg New Energy Finance, global sales of gas-powered cars may well have peaked in 2017, representing a significant milestone in the transition to electric vehicles.

Demand for gas cars dropped in 2018 and 2019, and then plummeted in 2020 as a result of the coronavirus pandemic.  While sales are surely picking up as the pandemic ebbs, the increasing demand (and supply as well) for plug-in vehicles is likely to put gas-powered cars in a state of permanent decline.

Global EV sales are projected to go from 3.1 million last year to 14 million in 2025.  The growth is being driven by falling battery prices, government policies, and increasing choices of vehicles.  Virtually all automobile manufacturers are introducing electric vehicles over the next couple of years and increasing numbers of them are planning a complete transition to EVs in the near future.  Projections are that EVs will account for the majority of new car sales by 2035.

While all this progress is encouraging, there are still over a billion gas- and diesel-powered cars on the road and the fleet turns over slowly.  The current average operating life of cars here in the US is 12 years.

To reach the net-zero carbon emission goals by 2050 as many governments have mandated, additional policies and regulations will be needed.  For example, electric cars will need to account for essentially all new sales by 2035, not just the majority.  Reaching net-zero by mid-century will require all hands on deck, including trucks and heavy commercial vehicles that have barely started to become electrified.

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New Analysis Suggests We Have Already Hit Peak Internal Combustion Engine

Photo, posted December 23, 2017, courtesy of Davide Gambino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenhouse Gas Emissions From Water Reservoirs | Earth Wise

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A new study by researchers from Washington State University and the University of Quebec at Montreal looked at greenhouse gas emissions from water reservoirs.  It is perhaps surprising to think that water reservoirs are a source of greenhouse gas emissions at all, but that much was already known.  The new study found that those emissions are actually around 29% higher than previously thought.

Overall, the researchers found that the world’s water reservoirs annually produce methane, carbon dioxide, and other greenhouse gases at an amount equivalent to 1.07 billion tons of carbon dioxide.   That is a small fraction of the 36 billion tons produced by fossil fuels and other industrial sources, but it is by no means a negligible amount.   In fact, it is more greenhouse gases than emitted by the entire country of Germany, which is the world’s sixth largest emitter.

Decomposing plant matter near the bottom of reservoirs fuels the production of methane, which is far more potent than carbon dioxide in warming the atmosphere.  This methane degassing accounts for about 40% of emissions from reservoirs.

The study is particularly important because it may be possible to reduce methane emissions from reservoirs by selectively only withdrawing water from near the reservoirs’ surface, which tends to be relatively methane-poor compared to greater depths.  In a related study, reducing withdrawal depth by 10 feet in a Malaysian reservoir reduced methane degassing emissions by 92%.

Human-generated greenhouse gas emissions come from a surprisingly wide range of sources and it is worthwhile studying as many of them as possible in the hope of finding additional ways to reduce the total.

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Greenhouse gas emissions from water reservoirs higher than previously expected

Photo, posted July 22, 2016, courtesy of Iain Merchant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Farming Productivity | Earth Wise

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The future potential impacts of anthropogenic climate change on global agricultural systems has been well studied, but how human-caused climate change has already affected the agricultural sector is not as well understood.  But a new study led by researchers at Cornell University and supported by the USDA National Institute of Food and Agriculture and the National Science Foundation examined this issue. 

Despite important agricultural breakthroughs in technology, fertilizer use and global trade during the past 60 years, it turns out that the climate crisis is already eroding farm productivity.  According to the study, which was recently published in the journal Nature Climate Change, global farming productivity is 21% lower than it could have been without climate change.  This is the equivalent of losing approximately seven years of farm productivity increases since the 1960s. 

The researchers developed a model linking annual changes in weather and productivity with output from the latest climate models over six decades to quantify the effect of anthropogenic climate change on what economists call “total factor productivity.” This measure captures the overall productivity of the agricultural sector. 

The research team reviewed 200 variations of the model, but the results remained largely consistent:  anthropogenic climate change is already slowing down global food production.  The researchers say the historical impacts of climate change have been larger in naturally warmer climates, like in parts of Africa, Asia, and Latin America.   

Climate change is not some distant problem to solve in the future.  It is already having an impact on the planet and it needs to be addressed now.

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Climate change cut global farming productivity 21% since 1960s

Photo, posted October 2, 2013, courtesy of the United Soybean Board via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fighting Zombie Fires | Earth Wise

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Peat fires are a global threat to both economies and the environment.  They generally burn a smaller area than fast-moving forest fires, but they can burn up to ten times more fuel matter per acre, producing far more smoke and far more carbon emissions.  They ignite very easily, are notoriously difficult to put out, all while releasing as much as 100 times more carbon into the atmosphere than flaming fires.  Some smoldering peat megafires are the largest and longest burning fires on Earth and are responsible for as much as 15% of annual global greenhouse gas emissions.

Peat fires are known as “zombie fires” because of their ability to hide and smolder underground and then reemerge as new flames days or weeks after they were supposedly extinguished.

Firefighters use billions of gallons of water to tackle a peat fire.  For example, fighting the 2008 Evans Road peat fire in North Carolina used up 2 billion gallons of water.  When water alone is used to extinguish peat fires, it tends to create large channels in the soil, which diverts water from nearby smoldering hotspots.  This is one reason that it is so difficult to extinguish a peat fire.

Researchers at Imperial College London have combined water with an environmentally friendly fire suppressant – one already used on flaming wildfires – and tested its use on peat fires.  They found that adding the suppressant to water helped them put out peat fires nearly twice as fast as using water alone, while using only a third to half of the usual amount of water.  The suppressant reduces the surface tension of the liquid, making it less likely to create large channels.  Instead, the liquid flows uniformly through the soil.  This could be an important tool in battling peat fires.

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‘Magical’ fire suppressant kills zombie fires 40% faster than water alone

Photo, posted in August, 2011, courtesy of Chris Lowie / USFWS 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.

Prickly Pear As A Sustainable Crop | Earth Wise

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The fruits and pads of opuntia, better known as prickly pear cactus, find their way into people’s diets in many arid and semi-arid places around the world.  In Mexico, the pads are known as nopales and are used in a variety of dishes.  The pears themselves are used in jams, salads, and juices.

A five-year study by the University of Nevada Reno College of Agriculture, Biotechnology & Natural Resources investigated the prospects for cactus pear to become a major crop like soybeans and corn and to help provide a biofuel source.

As the climate changes, dry areas are going to get dryer and drought issues will increasingly affect traditional crops.

The study looked at the particular opuntia species called the spineless cactus pear and found that it had the highest fruit production while using up to 80% less water than some traditional crops.  Cactus pear can be used for both human consumption and livestock feed.  As a perennial crop, once the fruit and pads are harvested for food, the remaining biomass can be used for biofuel production.

Corn and sugar cane are the most utilized bioenergy crops right now, but these use three to six times more water than cactus pear.  The cactus pear productivity is on par with corn and sugar cane, but not only do they use a fraction of the water, they also have higher heat tolerance.

Over 40% of land area around the world is classified as semi-arid or arid.  There is enormous potential for planting cactus for carbon sequestration.  If nothing else, it makes great sense to grow cactus pear crops in abandoned areas that are marginal and may not be suitable for other crops.

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Study shows cactus pear as drought-tolerant crop for sustainable fuel and food

Photo, posted April 16, 2020, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Pandemic And Global Temperatures | Earth Wise

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The early months of the Covid-19 pandemic last year saw dramatic reductions in travel and many forms of commerce.  With much of human activity greatly curtailed, greenhouse gas emissions were greatly reduced.   And yet, all of that did not slow down global warming: 2020 ended up tied with 2016 as the warmest year on record and atmospheric greenhouse gas levels reached a new high.

In order to understand how this came about, it is necessary to understand the complex climate influences of different types of emissions from power plants, motor vehicles, industrial facilities, and other sources.  The fact is that some types of pollution actually have a cooling effect rather than contributing to global warming.

Tiny industrial pollution particles called aerosols actually make clouds brighter, causing them to reflect away more solar heat from the surface of the planet.   During the drastic shutdown last year, the biggest emissions decline was from the most polluting industries.  The reduction of aerosols had immediate, short-term effects on temperatures.  These types of pollutants are very bad for human health, but when they are present, they do have the effect of reducing temperatures.

It is important to keep in mind that carbon dioxide spreads through the Earth’s atmosphere and stays there for a century or more, trapping heat on a global scale.  Industrial aerosols stay relatively concentrated in the region where they are emitted and are often removed by rain and winds within a few weeks.  So, their cooling effect doesn’t spread very far or last very long.

Overall, the initial pandemic slowdown probably didn’t have any real long-term impact on the climate but over the short term, the effects were not as simple as one might expect.

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Covid-19 Cut Gases That Warm the Globe But a Drop in Other Pollution Boosted Regional Temperatures

Photo, posted July 7, 2020, courtesy of Joey Zanotti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Positive Tipping Points And Climate | Earth Wise

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A tipping point is a moment when a small change triggers a large and possibly irreversible response.

There has been much discussion of various tipping points that could accelerate climate change in catastrophic ways.  A recent paper from researchers at the University of Exeter in the UK discusses a couple of tipping points that could accelerate positive progress on mitigating climate change.

Electric vehicles account for only 2-3% of new car sales globally. In Norway, this figure is more than 50%, mostly thanks to policies that make electric cars the same price to buy as conventional cars.   According to the Exeter study, when EVs cost the same to manufacture as conventional cars, it will be a global tipping point.  China, the EU, and California together are responsible for half of the world’s car sales and each of these has targets to rapidly decarbonize their economies and policies in place to speed the transition to electric vehicles. 

Decarbonizing electric power is the other potential positive tipping point.  In Europe, carbon taxes on top of increasing renewable energy generation have tipped coal into unprofitability as they have led to the irreversible destruction of coal plants.  Globally, renewables are already generating electricity cheaper than fossil fuels in many countries.  Decarbonizing global power generation would in turn help accelerate decarbonization of large parts of transportation, heating and cooling, and industry.

These potential positive tipping points are by no means inevitable.  Appropriate policies are needed to overcome various barriers to the clean energy transition.  But major changes in transportation and electric power would have a tremendous impact on the global effort to combat climate change.

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Positive ‘tipping points’ offer hope for climate

Photo, posted July 14, 2020, courtesy of Jim Champion via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Caspian Sea And Climate Change | Earth Wise

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According to the National Oceanic and Atmospheric Administration, global sea levels have been rising over the past century, and the rate has increased in recent decades.  Sea levels are currently rising about one-eighth of an inch every year.

Sea level rise is caused primarily by two factors related to climate change:  the added water from melting glaciers and ice sheets, and the expansion of seawater as it warms.  While climate change is causing global sea levels to rise, higher temperatures in other regions are having exactly the opposite effect.  The water levels are falling.

According to researchers from the University of Bremen in Germany, the Caspian Sea is a perfect example of how a body of water will change.  While it is named a sea due to its size and high salinity, the Caspian Sea is actually a lake.  In fact, it’s the largest lake in the world.  Its largest inflow is the Volga River and it has no natural connection to the ocean.  Its water level is determined by the proportional influences of inflow, precipitation, and evaporation.  Climate change is causing increased evaporation, which leads to a declining water level. 

According to the research team, the water level of the Caspian Sea could fall by 29 to 59 feet during this century.

The Caspian Sea is surrounded by Kazakhstan, Turkmenistan, Iran, Azerbaijan and Russia.  It’s an important regional water reservoir, and a biological and commercial center. 

The researchers hope the Caspian Sea will be used as an example in scientific research to assess the vulnerability of other regions to falling water levels.

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Photo, posted October 31, 2016, courtesy of Amanderson2 via Flickr.

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