factors

Why Was the Summer So Hot? | Earth Wise

September 4, 2023 By EarthWise Leave a Comment

Many places around the world have experienced extraordinary heat waves this summer. The 31 days of high temperatures 110 degrees or more in Phoenix is a prime example but many other places suffered from extreme and relentless heat. Why did this happen?

The overarching reason is climate change, which has warmed the Earth by 2.2 degrees Fahrenheit since the preindustrial era. This change on a global level is enough to make heatwaves far more likely. For example, the concurrent heatwaves in Europe and North America were 1000 times more likely to have occurred because of climate change.

But there hasn’t been a sudden increase in global temperature that would make this summer so much hotter. Instead, what really has happened is three other factors all came into play at the same time.

The first is the 2022 eruption of Hunga Tonga-Hunga Ha-apai, which is an underwater volcano in the South Pacific. That eruption did not produce much in the way of planet-cooling aerosols in the atmosphere. Instead, it vaporized huge amounts of seawater, sending water vapor into the atmosphere, which helps trap heat.

The second is a change in the amount of energy radiating from the sun. That actually rises and falls a small amount every 11 years. Currently, it is in the upswing and will reach its next peak in 2025.

Finally, there is the arrival of the El Niño in the Pacific, whose balmy ocean waters radiate heat into the air.

The combination of all these factors when added to the already warming climate is a recipe for temperatures to soar to uncharted highs. We can expect more heat waves, forest fires, flash floods, and other sorts of extreme weather.

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It’s Not Just Climate Change: Three Other Factors Driving This Summer’s Extreme Heat

Photo, posted February 27, 2017, courtesy of Giuseppe Milo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Why Are Insect Populations Declining? | Earth Wise

June 16, 2023 By EarthWise Leave a Comment

The world is experiencing a decline in overall insect populations as well as a collapse in insect diversity. A recent special issue of the journal Biology Letters discusses the major causes of this alarming trend.

According to the study, the primary causes of the worldwide decline in insect biomass are land-use intensification in the form of greater utilization for agriculture and building development, climate change, and the spread of invasive animal species as a result of human trade.

The study concludes that it is not just these factors that are driving the global disappearance of insects, but also that these three factors are interacting with each other. For example, ecosystems that are deteriorated by humans are more susceptible to climate change and so are their insect communities. Similarly, invasive species can establish themselves more easily in habitats damaged by human land-use and displace native species. Many native insect species decline or go extinct while others – often invasive species – thrive and increase, leading to decreasing insect diversity. Warming temperatures are making many locations undesirable for various insect species and they often cannot migrate to anyplace better.

Declining insect populations and diversity results in concomitant declines in plant species that depend on pollinators. This in turn threatens the stability of entire ecosystems.

The researchers advocate for continued monitoring of insect diversity across many habitats and countries and propose the creation of a network of interconnected nature reserves such that species can move from one to another.

We often think of insects as pests, but they are a crucial part of the world’s ecosystems.

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The reasons why insect numbers are decreasing

Photo, posted April 17, 2011, courtesy of Dean Morley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Lower Power Sector Emissions | Earth Wise

September 16, 2021 By EarthWise Leave a Comment

A combination of factors led to emissions from the U.S. power sector dropping 10% between 2019 and 2020, which was the largest one-year drop measured since annual reports first began being published in 1997.

The coronavirus pandemic was certainly a contributing factor, but the drop in emissions is part of a long-term trend being driven by increasing reliance on renewable energy sources, diminishing use of coal, and improving energy efficiency.

Between 2000 and 2020, power generation from solar, wind, and geothermal generation more than doubled. Coupled with the declining use of coal power, power sector emissions during that period dropped by 37% even though the U.S. gross domestic product grew by 40% over the same years. Overall, at this point zero-carbon electricity sources – which include wind, solar, geothermal, hydropower, and nuclear power – provide about 38% of U.S. electricity.

The Biden Administration has set a target of 100% zero-carbon power by the year 2035. Given that the costs of wind and solar power continue to fall, there are power companies pushing for setting an intermediate goal of 80% clean power by 2030.

According to recent research, the increasingly attractive cost of renewable power along with the job creation associated with it means that reaching at least 90% clean power by the year 2035 could be achieved at no extra cost to consumers. Being able to separate economic growth from emissions makes it far more likely that the goals of decarbonization can be met without encountering economic resistance.

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U.S. Power Sector Sees Biggest One-Year Drop in Emissions in More Than Two Decades

Photo, posted June 30, 2019, courtesy of Stephen Strowes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Giant Jellyfish | Earth Wise

August 28, 2020 By EarthWise Leave a Comment

There have been recent news stories about giant jellyfish washing ashore from Maine to the south coast of Massachusetts. These stories have claimed that some of these lion’s mane jellyfish have been the largest on record and even might be the largest animals in the ocean.

The truth of these accounts is rather suspect. For one thing, it is rather difficult to measure the size of a jellyfish when it is out of the water. Gravity compresses and spreads out the bell portion of the animal, and that makes up the bulk of its mass. For example, a jellyfish bell that measures four feet across on the beach would appear to be much smaller if the animal was floating in the water.

Some claims that lion’s mane jellyfish are larger than blue whales date back a full century and are very much disputable. The claimed size certainly included the animal’s long tentacles, and such things hardly compare with a blue whale.

In any event, the current spate of jellyfish sightings is not necessarily that unusual. Many factors influence jellyfish populations, including water temperature and food supply. It is possible that warming water temperatures may be influencing the jellyfish population this year, but there is not enough data to know for sure.

People do need to be cautious around lion’s mane jellyfish. They do sting and while their stings are not as bad as those of a number of other species, they can be a problem for people who have allergic reactions. Furthermore, the stinging cells remain active in a jellyfish that has washed ashore.

Sightings of these animals are continuing, and reports of larger specimens continue as well, even if they don’t compare with blue whales.

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Jellyfish larger than blue whales?

Photo, posted September 13, 2015, courtesy Derek Keats via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Forests As Carbon Sinks | Earth Wise

April 21, 2020 By EarthWise Leave a Comment

Tropical forests are an important part of the global carbon cycle because they take up and store large amounts of carbon dioxide. Because of this, deforestation in the Amazon and other tropical forests is a major contributor to the growing CO2 levels in the atmosphere.

Therefore, climate models need to accurately take into account the ability of tropical forests to sequester carbon. It turns out that this is not such a simple matter. A new study by the International Institute for Applied Systems Analysis sought to determine how much detail about tropical forests is needed in order to make valid assumptions about the strength of forest carbon sinks.

They looked at the role of both biotic factors – differences between plant species that are responsible for capturing more or less carbon from the atmosphere – and abiotic factors – local environmental factors like soil properties that also influence carbon sink strength.

It is generally assumed that more diverse forest communities capture available resources more efficiently as a result of complementary characteristics and preferences of certain species to specific conditions. Factors like soil texture and chemistry are also important. In general, the results show that abiotic and biotic factors interact with one another to determine how much carbon can be stored by the ecosystem.

Traditional projections of the role of tropical forests in storing carbon mostly rely on remote sensing techniques that integrate over large spatial areas. The new study shows that there can be large differences in the carbon storing ability of tropical forests and that more detailed models are needed to produce more accurate projections.

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Shedding light on how much carbon tropical forests can absorb

Photo, posted July 17, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Air Quality In The U.S.

November 13, 2019 By EarthWise Leave a Comment

Globally, poor air is a serious problem. According to the World Health Organization, exposure to air pollution is linked to the premature deaths of an estimated 7 million people every year. In fact, 91% of the people on the planet live in places where air pollution exceeds WHO guideline limits.

In the United States, air pollution has dramatically improved over the last four decades due in large part to federal regulations put in place under the Clean Air Act of 1970. Fine particulate matter (known as PM2.5) and other pollution, including ozone, sulphur dioxide, and nitrogen dioxide, have all decreased during this time span.

But according to recent research, this trend has unfortunately done an about-face. New data reveals that air pollution has increased nationally since 2016. An analysis of Environmental Protection Agency data by researchers at Carnegie Mellon University found that, on average, fine particulate pollution increased 5.5% across the country between 2016 and 2018.

This increase in fine particulate pollution was associated with nearly 10,000 additional premature deaths in the United States during that time period.

According to researchers, there are several factors likely causing this uptick in unhealthy air, including increases in both driving and the burning of natural gas. Wildfires out west are also thought to be a major contributor.

The researchers also suggest that a decrease in enforcement of the Clean Air Act may also be playing a role. The law put in place strict air pollution standards for vehicles, factories, power plants, and other sources, and is credited with saving hundreds of thousands of lives.

It’s time for clean air to be recognized as a basic human right.

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America’s Air Quality Worsens, Ending Years of Gains, Study Says

Photo, posted April 6, 2007, courtesy of Brett Weinstein via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Other Ways To Cut Vehicle Emissions

October 17, 2019 By EarthWise Leave a Comment

It is pretty clear that the way to drastically reduce vehicle greenhouse gas emissions is to switch as many vehicles as possible to electric power. As a result, more and more localities are putting in place policies that encourage electrification.

While there is no doubt that electrification is the long-term solution to vehicle emissions, a recent study by MIT and the Ford Motor Company found that, in the short term, there are some places in the US where electric cars are not the best way to reduce emissions.

The study looked at a variety of factors that affect the relative performance of vehicles. These include the role of low temperatures in reducing battery performance, regional differences in the average number of miles driven annually, and significant differences in the way electricity is generated in different parts of the US.

The results showed that electric vehicles definitely provide the greatest impact in reducing greenhouse gas emissions for most of the country – and particularly on both coasts and in the south – but that there are some places in the upper Midwest where the greatest reduction would be achieved by the use of lightweight gasoline-powered vehicles.

In places like parts of Wisconsin and Michigan, it is mostly rural, there are cold winters, and electricity is predominantly generated by coal-powered plants. In these places, if gas-powered lightweight cars were to be used, the overall benefit would be greater than that of electric cars. Unfortunately, there are no high-volume lightweight gasoline-powered mid-sized cars on the market in the US. Ironically, the only cars of that class using lightweight aluminum construction are Teslas.

While electric cars are truly the long-term solution, the study does demonstrate the benefits of reducing the weight of vehicles.

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What’s the best way to cut vehicle greenhouse-gas emissions?

Photo, posted February 9, 2018, courtesy of Dave Field via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Rising Seas On The East Coast

June 6, 2018 By EarthWise Leave a Comment

Global sea levels are rising by about a tenth of an inch per year, but in some places, the rise is faster… much faster. From 2011 to 2015, sea levels rose up to 5 inches – an inch per year – in some locales along the Eastern Seaboard. Places like Norfolk, Virginia and Miami are experiencing so-called sunny day flooding, something that had not been expected for decades according to climate projections. So, what is going on?