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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.

Right Whales And The Warming Atlantic | Earth Wise

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The warming of the Atlantic Ocean has driven the critically endangered North Atlantic right whale population from its traditional and protected habitat.  This has exposed the whales to more lethal ship collisions, increased entanglements with commercial fishing gear, and greatly reduced calving rates.

Since 2010, the calving rate has declined, and the right whale population has dropped by an estimated 26%.  Ten years ago, there were about 500 North Atlantic right whales; now there are an estimated 356.

These are some of the best studied whales in the oceans; scientists basically recognize each individual whale and when they are the victims of ship collisions or fishing entanglements, it is easy to identify which animal was killed.

Because of the warming climate, the Atlantic Meridian Overturning Circulation – an important system of surface and deep currents – has slowed down, causing the Gulf Stream to move north.  This has injected warmer and saltier water into the Gulf of Maine.  The warming Gulf of Maine has reduced the abundance of copepods, tiny crustations that are the favorite snack of right whales.   This has reduced whale calving rates and forced the whales to move north to the cooler waters of the Gulf of St. Lawrence.

For the past 6 years, more and more right whales have been observed feeding in the Gulf of St. Lawrence, where there were no protections in place to prevent ship strikes and fishing gear entanglement.  In 2017 alone, 17 right whale deaths were confirmed.

According to a recent report from Cornell University and the University of South Carolina, unless its management is improved, right whale populations will decline and potentially become extinct in the coming decades.

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Warming Atlantic forces whales into new habitats, danger

Photo, posted December 8, 2016, courtesy of Sea to Shore Alliance/NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Snakes Near A Plane | Earth Wise

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San Francisco International Airport is the seventh-busiest airport in the United States.  In a typical year, approximately 55 million people pass through SFO on their way to destinations throughout North America and beyond.

At some point during their journey to or from the terminals at SFO, each one of those people will pass by a seemingly unremarkable 180-acre parcel of land.  Surrounded by highways and train tracks, the soggy and overgrown vacant lot isn’t just home to rows of power lines.  It’s also home to the world’s largest population of the beautiful and highly endangered San Francisco garter snake.   

According to a recent study conducted by the U.S. Geological Survey, there are approximately 1,300 San Francisco garter snakes at SFO’s West of Bayshore property – the greatest concentration of these snakes ever recorded.

Conservationists have long known that the San Francisco garter snake was in trouble.  In fact, it landed on the U.S. Fish and Wildlife Service’s very first endangered species list, which was published in 1967.  Over the years, agricultural, commercial, and urban development have destroyed much of its wetland habitat, as well as much of its primary food source, the California red-legged frog.  The snakes have also been a popular target for poachers and collectors.

Since 2008, SFO has been working with the USFWS on a recovery strategy for the species.  Together, they’ve made enhancements to the West of Bayshore habitat, including building rainfed ponds and deepening existing wetlands.  They have also added fences to protect habitat and prevent illegal collection.

But low population counts at other locations means the recovery for the San Francisco garter snake is far from over. 

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Combining genetic and demographic monitoring better informs conservation of an endangered urban snake

A San Francisco Airport Site Is Crawling With Snakes—And That’s a Good Thing

Photo, posted April 16, 2011, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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.

Wild Pigs And The Environment | Earth Wise

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There are millions of wild pigs in the world with the largest numbers in the United States and Australia but significant numbers in South America, Europe, and China.  In the US, there are as many as 9 million feral swine living in 38 states.  A conservative estimate indicates that they cause about $1.5 billion in property and agricultural damage each year in this country.

Researchers in Australia have studied the climate damage wild pigs are causing across five continents.  According to the study, by uprooting carbon trapped in soil, wild pigs are releasing over 5 million tons of carbon dioxide annually, which is the equivalent of 1.1 million cars.

When soils are disturbed from humans plowing a field, or from wild animals uprooting, carbon is released into the atmosphere.  According to the researchers, wild pigs are just like tractors plowing through fields, turning over soil to find food.

The study used predictive population models coupled with advanced mapping techniques to pinpoint the damage wild pigs are causing.  According to the models, pigs are currently uprooting an area between 14,000 and 47,000 square miles, which is an enormous amount of land.  The effects are not just on the health of the soil and on carbon emissions.  This much damage also threatens biodiversity and food security.

Wild pigs are basically a human-caused problem, being either feral descendants of domestic swine, or hybrids of domestic swine and wild boars.  Wild pigs are prolific and their numbers have been expanding rapidly  Controlling their populations will require cooperation and collaboration across multiple jurisdictions.

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The climate impact of wild pigs greater than a million cars

Photo, posted July 1, 2017, courtesy of Shiva Shenoy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas In The Maldives | Earth Wise

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The Republic of Maldives is an archipelago in the Indian Ocean, southwest of Sri Lanka and India and about 400 miles from the Asian mainland.  It is one of the world’s most geographically dispersed sovereign states, the smallest Asian country by land area, and, with a little over 500,000 inhabitants, the second least populous country in Asia.  With its spectacular scenic beauty, it is also a premier tourist attraction.

With more than 80% of its 1,190 coral islands standing less than 1 meter above sea level, the Maldives has the lowest terrain of any country in the world.  As a result, the Maldives is particularly vulnerable to the sea level rise associated with climate change.

Some studies predict a grim future for the Maldives as well as other low-lying islands.  One study concluded that the islands could become uninhabitable by 2050 as wave-driven flooding becomes more common and freshwater becomes limited.

The Maldives government has explored plans to purchase land on higher ground in other countries.  Planners are also working to enhance the resilience of the country’s current islands.   An example is Hulhumalé, a newly constructed artificial island northeast of the country’s capital, Malé.

Construction of Hulhumalé began in 1997 and it now covers 1.5 square miles, making it the fourth largest island in the Maldives.  Its population is now more than 50,000, with more than 200,000 expected to eventually move there.  The new island, built by pumping sand from the seafloor onto a coral platform, rises about 2 meters above sea level.  The extra height could make the new island a refuge for Maldivians driven off lower-lying islands by the rising seas.

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Preparing for Rising Seas in the Maldives

Photo, posted June 15, 2009, courtesy of Elena N via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Banning Short Plane Flights | Earth Wise

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Almost everything we do ultimately results in greenhouse gases entering the atmosphere and therefore has an impact on the climate.  But some activities have much more impact than others.  The aviation industry is responsible for about 5% of global warming.

This doesn’t seem like that large a contribution, but only a very small percentage of the world’s population flies frequently and even in richer countries, only around half the population flew in any given year (at least before the pandemic.)

Flying is generally the only practical option for most long-haul trips and unless people give up on seeing the world or conducting global business in person, they are not going to give up taking air trips.

But shorter flights are a different story.  If you are planning to take a reasonably short trip in France, a plane will soon no longer be an option.  The French government says that flights will be banned on any route where the trip could be made on a train in 2.5 hours or less.  The driving force is the reduction of CO2 emissions.  A plane trip emits an average of 77 times more CO2 per passenger than taking a train on the same route.

The Netherlands and Belgium are also considering bans on short-haul flights and Austrian Airlines recently replaced its Vienna-to-Salzburg flights with train service.

Advocates of the flight bans say that not only does taking the train significantly reduce a traveler’s carbon footprint, but it can be cheaper and actually faster than a plane when factoring in the time spent getting to airports, standing in security lines, getting on and off planes, and so on.  Europe’s extensive train system makes this approach broadly practical. Unfortunately, here in the U.S., it is not quite that easy.

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France Will Ban Short Flights That Could Be Replaced By a Train Trip

Photo, posted December 17, 2016, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Harvesting Water From Air | Earth Wise

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Developing new technologies that harvest water from the air is a growing field of research driven by the fact that more and more people live in areas where fresh water is in short supply.  Estimates are that roughly half the world’s population lives in regions with severe freshwater shortages for at least one month each year.

We have previously discussed some of the novel approaches that researchers are taking to enhance water harvesting.  The work at UC Berkeley using metalorganic frameworks is a notable example.

One of the key problems in harvesting water from air is that many droplets that condense from water vapor in the air are too small to be collected and when they cover a surface, they can actually impede further condensation.

University of Texas at Dallas researchers have developed a novel surface that encourages tiny water droplets to move spontaneously into larger droplets.  The droplets actually self-climb along an oil, ramp-shaped meniscus.  The meniscus acts like a bridge along which microdroplets spontaneously climb upward and coalesce with larger water droplets.  They call this the coarsening droplet phenomenon.  It is enabled by a liquid lubricant with a unique hydrophilic nature.  They actually discovered the lubricant’s special properties by accident when in a lubricant test they observed smaller water droplets propel themselves into larger droplets.

Based on experimental data, the coarsening surface enhances the water harvesting rate 200% higher than other techniques.  The team continues to work on ways to use the new lubricant to make sustainable water harvesting systems that are mobile, smaller in size, lower in weight, and less expensive.  If they are successful, they will essentially be able to harvest water anywhere that has air.

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New Physical Phenomenon Aids Harvest of Water from Air

Photo, posted April 26, 2014, courtesy of Toukou Sousui via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transmission Lines And Wildlife Habitat Connectivity | Earth Wise

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Electrical transmission lines and their support towers tend to be a blight on the landscape but are something modern society cannot avoid.  Power transmission networks – with towers every 200 meters or so of line – are in place throughout the world’s developed nations.  Another common feature of developed nations is the fragmentation of animal species caused by human activity breaking up their natural habitats.

It is important for biodiversity conservation for animals to get their environments connected.   It turns out that transmission line infrastructure can provide an important tool for reconnecting wildlife habitats.

In a study conducted in Spain’s Andalusia region, scientists planted native shrubs and seedlings under six towers along power lines running through cereal cropland.  The area of each tower base was 100 square meters.

Compared to four control sites, the researchers measured increased population density and diversity among arthropods and small mammals observed in the four-year study. 

Enhancing connectivity through networks of habitat corridors or stepping-stone patches has become a key concept in conservation biology and landscape ecology.  Renting or buying large parcels of land to connect protected natural areas to one another would be cost prohibitive but planting suitable native shrubs and other flora under existing transmission line networks can provide many of the same benefits.

In general, power companies pay rent to landowners – often farmers or agribusinesses – for the rights to place towers on their land.  Because it is difficult to work the areas under towers with farm equipment, that space is typically unused, which opens the door to low-cost efforts by environmentalists.

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Electrical transmission lines have power to enhance habitat connectivity for wildlife

Photo, posted April 29, 2018, courtesy of Georgi Todorov/digitalnovas.com via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New Fishway Technology | Earth Wise

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Freshwater fish populations have declined by more than 80% over the past forty years across the globe.  This is in part due to hundreds of thousands of dams, weirs, and barriers stopping their movements.  These river barriers have disrupted fish reproduction cycles the world over by preventing river fish from migrating to spawn.

Fishways or fish ladders are waterways constructed on or around obstructions in order to provide passageways for fish and other aquatic species.  Often, they consist of a series of small overflow weirs and pools constructed in the form of steps.  Fish need to jump from one pool to another to migrate to the upstream.  Such fish ladders require a large space to construct.  These and several other types of fishways tend to be expensive to install and maintain and are not always successful in allowing fish to get to where they need to go.

Researchers at the University of New South Wales in Australia have come up with an ingenious new type of fishway.  Called a “tube fishway”, it is a low-cost and low-energy installation that works by pumping fish at high velocity – protected by a cushion of bubbly water – through a tube running over the obstructing barrier to deliver them safely into the water on the other side.

They successfully demonstrated a prototype system on a rugged slope behind a campus building that transported fish from one tank to another about 25 feet up the slope.

Fish are attracted into the chamber by suitable geometry and the system uses the energy available from the upper reservoir to lift the fish.  Modeling shows that the system will work for pipes as large as three feet in diameter and could lift fish more than 300 feet vertically. 

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New fishway technology to get fish up and over those dam walls

Photo, posted October 19, 2019, courtesy of Andrew Harvey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bees Threatening Bees | Earth Wise

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Domesticated honeybees are an essential part of our agricultural system, being responsible for one in every three bites of food Americans consume and contributing $15 billion a year to the value of the nation’s crop production.  Millions of bee colonies are trucked across the country every year to pollinate cranberries, melons, broccoli, blueberries, and cherries, and also to produce honey.

After the growing seasons, honeybees are trucked to various locations to rest and rebuild their population and to replenish bees lost to disease and pesticides.  Some of these locations are in national forests.  Thousands of hives belonging to 112 apiaries are currently permitted in national forests by the Department of Agriculture.  This presents a problem because these hives are being permitted on public lands with virtually no environmental review and with little consideration of the impact these colonies can have on local wild bee populations.

The 4,000 wild bee species in the U.S. consume up to 95% of local available pollen.  Nearly 40 federally listed threatened or endangered species of bees, butterflies, and flower flies depend on national forest land for their survival.  And now the pollinators in these places, which were once refuges for these species and others, increasingly face competition from millions of domesticated honeybees.

Honeybees are super-foraging machines and are literally taking the pollen out of the mouths of other bees and pollinators.  Honeybees themselves have been facing numerous problems from habitat loss, pesticides, and other stress factors.  So, what is happening is essentially a pollinator habitat crunch that carries long-term implications for the U.S. food supply.  We need to find some answers and the sooner the better.

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Will Putting Honey Bees on Public Lands Threaten Native Bees?

Photo, posted August 9, 2015, courtesy of Tak H. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change and Komodo Dragons | Earth Wise

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The Komodo dragon is the world’s largest and most iconic lizard.  Growing up to 10 feet long and weighing up to 360 pounds, Komodo dragons are endemic to five islands in southeast Indonesia, four of which are part of Komodo National Park, as well as a fifth that has three nature reserves.  Komodo dragons have existed on earth for at least four million years, and it’s estimated that 4,000 of them survive in the wild today.

But according to a new study by researchers from the University of Adelaide and Deakin University in Australia, Komodo dragons could soon be driven to extinction.  The research team found that the impacts of both global warming and sea level rise are likely to cause a sharp decline in  available habitat for Komodo dragons.  Current conservation strategies are not enough to avoid climate-driven Komodo dragon population declines. 

The study, which was recently published in the journal Ecology and Evolution, involved close collaboration with Komodo National Park and the Eastern Lesser Sunda Central Bureau for Conservation of Natural Resources.

Climate-change-informed decisions should be a common part of conservation practice.  According to the research team’s conservation model, Komodo dragons on two of the five Indonesian islands are less vulnerable to climate change.  But those two islands might not be enough for the survival of the species.  Conservation managers may need to translocate Komodo dragons in the future – to sites where these animals have not been found for decades – in order to protect the species from extinction. 

Without taking immediate action to mitigate climate change, the research team says many range-restricted species like Komodo dragons are at risk of extinction.

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Climate change threatens Komodo dragons

Photo, posted August 6, 2016, courtesy of Tony Alter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sharks On The Decline | Earth Wise

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During the past 70 years, global shark populations have been on the decline.   Many species have become threatened or endangered.  Conservation efforts have been underway in many places, but shark populations continue to be at risk because of over-fishing and habitat loss.

A comprehensive study by marine biologists at Texas A&M University deployed more than 15,000 baited remote underwater video stations on 371 coral reefs in 58 countries.   The study included 59 different shark species in the Atlantic, Pacific and Indian Oceans.  The researchers were surprised to find that no sharks at all were detected in almost 20% of the locations surveyed and were almost completely absent from coral reefs in several nations. 

Scientists believe that demand for shark products, such as fins and meat, and bycatch (that is, sharks captured in nets by fisherman trapping other kinds of fish) are strong contributors to the widespread declines in shark numbers around the world.

The study shows that if corrective steps are not taken in regions where marine management is still ineffective, continued depletion of shark populations is highly likely. 

Sharks have important roles in marine ecosystems.  When their habitats deteriorate and their populations decrease, ecosystem stability and health is degraded because sharks help regulate prey populations.

Some countries, notably the Bahamas, are combating the problem by providing sanctuaries for sharks where fishing and harvesting is prohibited.  Such places support some of the healthiest shark populations in the world.  However, the decline of coral reefs is just another challenge facing shark populations around the world.

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Study Shows Alarming Decline In Shark Numbers Around The World

Photo, posted January 9, 2017, courtesy of Kris-Mikael Krister via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Beavers And The Warming Arctic | Earth Wise

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

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

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

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

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

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Beavers gnawing away at the permafrost

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

Earth Wise is a production of WAMC Northeast Public Radio.

Increasing Air Pollution | Earth Wise

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According to researchers from the University of Exeter, half of the world’s population is exposed to increasing air pollution despite global efforts to improve air quality.  The study, which was completed in conjunction with the World Health Organization, suggests that air pollution represents a major and growing threat to human health. 

For the study, which was recently published in the journal Climate and Atmospheric Science, the researchers reviewed global air quality trends between 2010 and 2016.  The research team examined those findings against a backdrop of global policies to reduce air pollution.  The researchers used ground monitoring data and satellite data to develop yearly air quality profiles for individual countries and regions. 

The scientists focused on fine particulate matter, which is a mixture of solid particles and liquid droplets found in the air.  Some of the particles, like dust, soot, or smoke, are large enough to be seen by the naked eye.  Others are so small that they can only be seen using a microscope.  Inhaling fine particulate matter can cause all sorts of health issues, including asthma, respiratory inflammation, and even promote cancer. 

For much of the world’s population, the consequences of polluted air are more deadly than war, violence, and many diseases.  According to the World Health Organization, more than four million deaths every year can be attributed to outdoor air pollution.  Some of the major sources of air pollution include coal-fired power plants, agriculture, transportation, and deforestation. 

The study found that low and middle income countries experience the highest burden of air pollution around the world, with the largest concentrations found in central and southeastern Asia.

More long term policies are needed to curb this growing threat to public health. 

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Half of the world’s population exposed to increasing air pollution

Photo, posted August 2, 2019, courtesy of Ron Reiring via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Troubles For Bees | Earth Wise

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Beekeepers in the United States lost nearly 44% of their managed honeybee colonies from April 2019 to April 2020, according to the 14th annual nationwide survey conducted by the nonprofit Bee Informed Partnership.  This was the second highest annual loss recorded since the surveys began.

The high loss rate over the past year was unusual in that winter losses were actually substantially lower than they have been in recent years.   The winter losses were 22.2%, which is 15.5 points lower than last year and 6.4 points lower than the average over the past 14 years.  On the other hand, summer losses were 32%, which is 12 points higher than last year and 10.4 points higher than the average.

In fact, the summer loss was the highest ever recorded and was only the second time that more bees were lost in the summer than in the winter.

Commercial beekeepers generally have lower losses than backyard and smaller operations.  Commercial honeybee colonies pollinate $15 billion worth of crops in the United States every year, so the health of these colonies is a critical issue for domestic food production and supply.

Beekeepers began noticing dramatic losses in their colonies in the early 2000s and ever since then, state and federal agricultural agencies, university researchers, and the beekeeping industry have been working together to try to understand the reasons for the population decline and to develop approaches to reduce these losses.

Winter loss has previously been the main focus of management activities since that period of the year is thought to be the most challenging for bee colonies.  This year’s results are driving a great deal of analysis of the possible causes for the dramatic summer colony losses.  Whatever they turn out to be, they represent more troubles for bees.

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Odd Year for U.S. Beekeepers Who Reported Lower Winter Losses but Abnormally High Summer Losses

Photo, posted April 14, 2013, courtesy of Paul Rollings via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Global Emissions And The Coronavirus Shutdown | Earth Wise

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With so much of industry and personal activity curtailed by coronavirus shutdowns across the globe, it is no surprise that greenhouse gas emissions have declined.  According to new research published in the journal Nature Climate Change, average daily global greenhouse gas emissions declined 17% by early April compared to 2019 levels.

If the reopenings around the world continue and the world actually reaches pre-crisis levels by the middle of June, total CO2 emissions for the year would likely end up lower by about 4%.   If various restrictions continue until the end of the year, total global emissions could decline by 7%.

The study analyzed emissions estimates for three levels of coronavirus shutdowns and across six sectors of the economy.  It looked at trends in 69 countries, all 50 U.S. states, and 30 Chinese provinces, representing in total 86% of the world’s population and 97% of global CO2 emissions.

For the first 4 months of the year, emissions from industry declined 19%, the power sector 7%, and public buildings and commerce 21%, compared to last year.  Unsurprisingly, home energy use actually went up by about 3%.

The findings of this study only represent the effects of a short-lived decline in emissions.  As economies open back up, there is no doubt that greenhouse gas emissions will rise back to pre-Covid-19 levels.

The study also reveals that making real changes in emissions will require more than just behavior changes.  Despite billions of people staying home, companies shut down, planes grounded, and cars off the road, we still managed to pump more than 80% of the usual amount of greenhouse gases into the air for the first quarter of the year.

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Global Emissions Fell 17 Percent Due to Coronavirus Shutdowns

Photo, posted May 7, 2020, courtesy of the MTA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fighting Malaria With Gene-Drive Technology | Earth Wise

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Malaria continues to be a major health hazard throughout the tropical and subtropical regions of the world. There were 228 million cases of malaria in 2018 and over 400,000 deaths. 

Malaria is a mosquito-borne infectious disease spread by 40 of the world’s 3,500 mosquito species.  So, efforts to control mosquito populations are the primary strategy to eradicate malaria.

A team led by Imperial College London has created a genetic modification that distorts the sex ratio of a population of Anopheles gambiae mosquitoes using “gene drive” technology.  The modification works by using a DNA-cutting enzyme to destroy the X chromosome during the production of sperm, which leads to predominantly male offspring, since females require two X chromosomes.  The modification is coupled to a gene drive to allow it to spread through a population in a very effective way.  A gene drive is a genetic engineering technology that propagates a particular modification by assuring that a specific form of a gene (or allele) will be transmitted with far more than the natural 50% probability.

The result of this is that mosquitoes produce more male offspring, eventually leading to no females being born and a total collapse in the population. The mosquitoes studied are the main malaria vector in sub-Saharan Africa.  The hope is that mosquitoes carrying a sex-distorter gene drive would be released in the future, spreading the male bias with local malaria-carrying populations and causing them to collapse.  Only female mosquitoes bite and take blood meals.  If the gene drive technology works in the field, it could be a game-changer in the fight to eliminate malaria.

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Malaria mosquitoes eliminated in lab by creating all-male populations

Photo, posted June 20, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Living In Extreme Heat | Earth Wise

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Global climate change has already left observable effects on the planet.  Glaciers have shrunk, trees are flowering sooner, plant and animal ranges have shifted, and so on. Many effects of climate change that scientists had predicted in the past are now occurring.  The loss of sea ice, intensifying heat waves, and accelerating sea level rise are some examples.

According to a new study recently published in the journal Proceedings of the National Academy of Sciences, climate change is going to affect humans earlier, harder, and more widely than previously projected.  The research team found that one billion people will be either displaced or endure insufferable heat for every one degree Celsius rise in global temperatures.  

Under a worst case climate scenario, land that one third of the world’s population currently calls home will be as hot as the hottest parts of the Sahara desert within 50 years.  Even under a more optimistic climate outlook, 1.2 billion people will still be exposed to temperatures outside the climate niche in which humans have thrived for at least 6,000 years.

The majority of the human population has always lived in regions where the average annual temperatures were between 43 degrees Fahrenheit and 82 degrees Fahrenheit.  These are ideal temperatures for human health and for food production.  But this temperature range is shrinking and shifting as a result of climate change. 

The study’s authors predict there will be more change in the next 50 years than there has been in the past 6,000 years.  They hope their findings will convince policymakers to accelerate their plans for emissions reductions and other climate mitigation strategies.   

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Future of the human climate niche

One billion people will live in insufferable heat within 50 years – study

Photo, posted November 22, 2008, courtesy of Ronnie Finger via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Too Many Bison | Earth Wise

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The population of large herbivores in Yellowstone National Park has undergone many dramatic changes over the course of time.  The numbers of both the iconic Rocky Mountain elk and bison have gone up and down as a result of human interactions.

Bison, of course, once were a dominant species from east of the Appalachians to west of the Rocky Mountains, with most of an estimated 30 million living on the Great Plains.  As the west was settled, bison populations plummeted and by the late 1800s, they were nearly extinct.

When Yellowstone was established, there were exactly 22 bison in the park.  By 1925, there were more than 750 in the park and culling of the herd in the park’s Lamar Valley was practiced for the next four decades.

The elimination of predators like grey wolves and cougars in the early 1900s caused both elk and bison populations to mushroom and both underwent culling.  When culling was ended in 1968, there were 4,000 elk and 100 bison.  Within 20 years, those numbers were 20,000 and 1,000.   Reintroducing wolves and cougars reduced the elk population to about 5,000, but bison numbers have continued to grow, now reaching about 4,000.

While the long-term recovery of the Yellowstone bison herd is a major conservation success story, the fact is that bison are powerful ecosystem engineers.  Large numbers of them disrupt species distribution across scrub steppe and grasslands because of what they eat, trample, and rub their horns and bodies on.  They have a tremendous capacity to limit the structure and composition of ecosystems.

Park administrators have complicated management decisions to make to take into account the often wide range of ecological effects that abundant large herbivores can have on ecosystems.

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Bison in northern Yellowstone proving to be too much of a good thing

Photo, posted August 10, 2016, courtesy of Brian Gratwicke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

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