human activity

Environmental DNA | Earth Wise

August 5, 2022 By EarthWise Leave a Comment

Marine protected areas are sections of the ocean where governments place limits on human activity. They are intended to provide long-term protection to important marine and coastal ecosystems. MPAs are important because they can protect depleted, threatened, rare, and endangered species and populations.

In January 2020, the Republic of Palau in the western Pacific Ocean created one of the world’s largest marine protected areas. The Palau National Marine Sanctuary covers 80% of the country’s economic zone and prohibits all extractive activity like fishing and mining over a 183,000 square mile area in order for the island nation to ensure its food security and grow its economy in the face of climate change.

The Marine Sanctuary is an ambitious enterprise. The question is how Palau can evaluate whether and how well it is working?

A team of scientists from Stanford University and Palau-based colleagues are making use of Environmental DNA – or eDNA – technology to monitor the large-scale marine protected area. eDNA is the cells, waste, viruses, and microorganisms that plants and animals leave behind. Samples of marine eDNA effectively provide a fingerprint of the organisms that have recently passed through the water in a given area. This gives scientists a way to assess an ecosystem’s biodiversity and keep track of the types of species inhabiting a specific area. Using eDNA, it is possible to keep track of all the organisms that live below the surface and learn about things we can’t even see.

The team has embarked on a program of periodic sampling of the waters off Palau and hope to be able to monitor the results of establishing the Marine Sanctuary.

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eDNA: Bringing biodiversity to the surface

Photo, posted June 12, 2013, courtesy of Gregory Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reshaping Our Planet | Earth Wise

July 12, 2022 By EarthWise Leave a Comment

Human activity – especially agriculture – has altered 70% of the land on our planet. According to a new report from the United Nations, damage to the Earth’s lands has put the planet on “crisis footing”.

Our health, our economy, and our well-being depend on land. The food we eat, the water we drink, and the air we breathe all rely on status of the land to at least some extent.

According to the report, up to 40% of the planet’s land is already degraded, affecting half of the people alive today. At current rates, an additional area nearly the size of South America will be degraded by 2050.

Degradation of land occurs in various ways, including deforestation, desertification, and the loss of wetlands or grasslands. All of these things are caused by human activities. As forests, savannas, wetlands, and mangrove swamps are converted to agriculture or are lost to urban expansion, greenhouse gas emissions rapidly increase, adding to the effects of climate change. The climate crisis, biodiversity loss, and land degradation are integrally linked.

Much of the blame for degraded landscapes is on humanity’s ever-expanding need for food and the modern farming systems that produce it. The global food system is responsible for 80% of the world’s deforestation, 70% of freshwater use, and is the greatest driver of land-based biodiversity loss. Modern agriculture has altered the face of the planet more than any other human activity.

The report urges efforts at restoration of land. Restoration can take multiple forms, including planting forests and shrubs or grazing livestock and growing crops between trees instead of clearing existing forests.

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UN Report Says Humanity Has Altered 70 Percent of the Earth’s Land, Putting the Planet on a ‘Crisis Footing’

Photo, posted June 20, 2010, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Sounds Of Coral Reefs | Earth Wise

June 23, 2022 By EarthWise Leave a Comment

Coral reefs around the world face multiple threats from climate change, pollution, and other impacts of human activity. Reef conservation and restoration projects must be able to monitor the health of reefs and that is not such a simple matter. Surveying reefs generally is labor-intensive and time consuming. But in a new study, scientists at the University of Exeter in the UK have found a new way to do it.

The fish and other creatures living on coral reefs produce a vast range of sounds. The meaning of these various sounds is for the most part unknown, but reefs nonetheless have distinctive sonic signatures.

The Exeter researchers decided to make use of machine learning technology. They trained a computer algorithm using multiple recordings of both healthy and degraded coral reefs. This essentially taught the computer to learn the difference between them. A computer can pick up patterns that are undetectable to the human year. This application of artificial intelligence can tell us faster and more accurately how a reef is doing.

The computer was then used to analyze a set of new recordings, and successfully identified reef health 92% of the time. The team then was able to use this technique to track the progress of reef restoration efforts.

It is generally much cheaper and easier to deploy an underwater hydrophone on a reef and leave it there instead of having expert divers make repeated visits to a reef to survey its status. Sound recorders and artificial intelligence could be used around the world to monitor the health of coral reefs and determine whether efforts to protect and restore them are working.

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AI learns coral reef “song”

Photo, posted January 11, 2015, courtesy of Falco Ermert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

People And The Earth’s Increasing Heat | Earth Wise

September 23, 2021 By EarthWise Leave a Comment

A new study by Princeton University and the National Oceanic and Atmospheric Administration had found clear evidence that human activity is the primary cause of the significant increase in heat stored in our planet. In fact, the study found that there is less than a 1% chance that natural variability is the sole cause of the increase.

The researchers looked at data from satellite observations to determine the amount of energy received by the earth and the amount reflected and emitted by the Earth. In a balanced physical system, the amount of incoming energy should equal the amount of outgoing energy. But the earth’s system is not balanced at this point. More energy is coming in than going out, which is driving changes in the climate system. There have been other studies looking at the human influence on the climate, but this new study is the first to examine a 20-year continuous satellite energy balance record to see if natural fluctuations in the climate system or human activities is the primary driver for the significant change in the planet’s energy balance.

The study examined 50 different climate models to look at this energy balance under scenarios where there was no human influence. These include changes in the sun’s output, volcanic eruptions, variations in pollution aerosols, and more.

The results, to no great surprise, are that increasing greenhouse gases over the last twenty years is by far the most important driver for the energy imbalance. This imbalance is what is driving rising temperatures, increasing sea levels, and causing other climate changes.

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Human activities responsible for rapid increase in Earth’s heat

Photo, posted May 6, 2021, courtesy of Marlis Borger via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Peatlands And Greenhouse Gas Emissions | Earth Wise

July 21, 2021 By EarthWise Leave a Comment

As the world seeks to reduce the greenhouse gas emissions that have been warming the climate, most of the focus has been on the primary contributors to the problem, such as the burning of fossil fuels. But there are many smaller contributors to greenhouse gas emissions that individually play only a minor role but collectively add up to significant amounts. One of these is the emissions from peatlands.

Peatlands are a type of wetland that occur in almost every country on Earth, covering 3% of the global land surface. They are terrestrial ecosystems in which waterlogged conditions prevent plant material from fully decomposing. As a result, the production of organic matter exceeds its decomposition, which results in a net accumulation of peat. Peatlands are, in fact, the largest natural terrestrial carbon store, storing more over 700 billion tons of carbon, more than all other types of vegetation combined.

Human activity, such as creating drainage in peatlands for agriculture and forest plantation, results in the release of over 1.6 billion tons of CO2 into the atmosphere each year. This constitutes 3% of all global greenhouse gas emissions caused by human activities.

Large numbers of people rely on peatlands for their livelihoods, so it is not reasonable for these emission-generating activities to be greatly curtailed. But researchers at the University of Leicester in the UK analyzed the potential effects of cutting the current drainage depths in croplands and grasslands on peat in half and showed that this could reduce CO2 emissions by more than 500 million tons a year. This equates to one percent of all greenhouse gas emissions caused by human activities.

There are numerous opportunities to reduce emissions a little bit at a time.

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Better peatland management could cut half a billion tonnes of carbon

Photo, posted August 17, 2013, courtesy of Joshua Mayer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

What Is An Endangered Species? | Earth Wise

March 3, 2020 By EarthWise Leave a Comment

Biodiversity is declining rapidly throughout the world and people are mostly the reason. Species are disappearing because of changes in land and sea use, the direct exploitation of organisms, climate change, pollution, and invasive alien species resulting from globalization. The challenges of conserving the world’s species are many and difficult. Among these challenges are determining which species are endangered and how and when to protect them.

What constitutes an endangered species is not necessarily obvious.

Extinction risk increases as a species is driven to extinction from portions of its natural range. Most mammal species have already been driven to extinction from half or more of their historic ranges because of human activities.

According to a recent survey of ordinary Americans, three-quarters of participants said that a species deserves special protections if it had been driven to extinction from any more than 30% of its historic range. This compares with the language of the U.S. Endangered Species Act that defines an endangered species as one that is “in danger of extinction throughout all or a significant portion of its range.”

Experts and decision-makers are more accepting of risks and losses because they believe greater protection would be impossibly expensive. Decision-makers tend to be influenced by special interest groups with a vested interest in not instituting protections.

Before human activities began elevating extinction risk, a typical vertebrate species would have experienced an extinction risk of 1% over a 10,000-year period. Current policies consider a 5% risk over 100 years to be acceptable. Policies consider whether we can afford to protect species. Given the dangers of declining biodiversity, we should ask whether we can afford not to.

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What Is An Endangered Species?

Photo, posted July 29, 2018, courtesy of Sergio Boscaino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Rising Threat Of Rising Seas | Earth Wise

February 3, 2020 By EarthWise Leave a Comment

Global sea level rose by about 6 inches during the 20th century. It is currently rising more than twice as fast and accelerating. The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass. Much of that meltwater comes from Greenland and Antarctica. But levels also rise because, as water warms, it expands. Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened. (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas. These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles. Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion. Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

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The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change Is Not Natural

July 5, 2019 By EarthWise Leave a Comment

It has been the overwhelming consensus of the scientific community for a long time that human activity and other external factors are responsible for the continuing rise in global temperature. Despite this widespread agreement, there have been those who argue that natural ocean cycles might be influencing global warming over the course of multiple decades.

A new study, published in the Journal of Climate, provides an answer to the question of how much influence natural cycles might have, and that answer is very little to none.

The study looked at observed ocean and land temperature data since 1850 and, apart from human-induced factors such as greenhouse gas concentrations, took into account other occurrences such as volcanic eruptions, solar activity, and air pollution peaks. The findings demonstrated that slow-acting ocean cycles do not explain the long-term changes in global temperatures.

Based on the study, the researchers can state with confidence that human factors like greenhouse gas emissions and particulate pollution, along with year-to-year changes caused by natural phenomena like volcanic eruptions or El Niño, are sufficient to explain virtually all the long-term changes in temperature. The idea that the oceans could have been driving the climate either in a colder or warmer direction for multiple decades in the past and therefore will do so in the future is unlikely to be correct.

A number of previous studies have compared flawed observations with flawed modeling results to claim that naturally-occurring ocean cycles have played a large role in global temperatures. The new study shows that such cycles have little influence on the climate. Reducing greenhouse gas emissions is really what we need to do.

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Global temperature change attributable to external factors, confirms new study

Photo, posted November 13, 2007, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Vulnerable Shorelines

May 21, 2019 By EarthWise Leave a Comment

Global climate change is having noticeable effects on the environment. For example, glaciers are shrinking. Plant and animal ranges are shifting and populations decreasing. And droughts, floods, and wildfires are becoming more frequent and more intense. According to the Intergovernmental Panel on Climate Change, the evidence indicates that the net damage costs of climate change are likely to be significant and to increase over time.

Our coastal shorelines, which are already stressed by human activity, pollution, storms, and invasive species, are one of many areas expected to be further threatened by climate change. Sea level rise and more intense and frequent storms are expected to erode and inundate coastal ecosystems and eliminate wetlands. Ocean acidification is also projected to disrupt marine environments.

But according to scientists at the Massachusetts Institute of Technology, seagrasses could play a key role in protecting these vulnerable shorelines from this onslaught. The MIT research team demonstrated how the ubiquitous marine plants dissipate wave energy and help protect against erosion, which could help mitigate damage from rising seas.

Using mathematical modelling and experiments, the MIT researchers were able to quantify for the first time how large and dense a continuous meadow of seagrass must be in order to provide adequate damping of waves in a given setting. They also found that seagrasses offer significant environmental benefits, including preventing beach erosion, protecting seawalls and coastal structures, improving water quality, and sequestering carbon.

Submerged aquatic vegetation, including seagrasses, provides an ecosystem service exceeding $4 trillion annually. Hopefully these findings can help provide useful guidance for seagrass restoration efforts.

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Seagrass’ strong potential for curbing erosion

The Effects of Climate Change

Photo, posted October 13, 2010, courtesy of the NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Deforestation in the Amazon Rainforest

May 30, 2017 By EarthWise

The Amazon rainforest is the biggest in the world, larger than the next two biggest combined. It covers over 3 million square miles, roughly the size of the lower 48 states. For this reason, it functions as a critical sink for carbon in the atmosphere.

The Threat Of Man-Made Earthquakes

April 14, 2017 By EarthWise

According to a new report from the U.S. Geological Survey, millions of people living in Oklahoma and parts of Kansas face significant potential for damaging earthquakes this year as a result of human activity. The only other part of the continental United States facing a similar danger is California, which has natural faults lines slicing through the state.