Day: November 16, 2021

Climate change is muting fall colors, but it’s just the latest way that humans have altered US forests

by Marc Abrams, Penn State

Fall foliage season is a calendar highlight in states from Maine south to Georgia and west to the Rocky Mountains. It’s especially important in the Northeast, where fall colors attract an estimated US$8 billion in tourism revenues to New England every year.

As a forestry scientist, I’m often asked how climate change is affecting fall foliage displays. What’s clearest so far is that color changes are occurring later in the season. And the persistence of very warm, wet weather in 2021 is reducing color displays in the Northeast and mid-Atlantic. But climate change isn’t the only factor at work, and in some areas, human decisions about forest management are the biggest influences.

Longer growing seasons

Climate change is clearly making the Northeast warmer and wetter. Since 1980, average temperatures in the Northeast have increased by 0.66 degrees Fahrenheit (0.37 Celsius), and average annual precipitation has increased by 3.4 inches (8.6 centimeters) – about 8%. This increase in precipitation fuels tree growth and tends to offset stress on the trees from rising temperatures. In the West, which is becoming both warmer and drier, climate change is having greater physiological effects on trees.

My research in tree physiology and dendrochronology – dating and interpreting past events based on trees’ growth rings – shows that in general, trees in the eastern U.S. have fared quite well in a changing climate. That’s not surprising given the subtle variations in climate across much of the eastern U.S. Temperature often limits trees’ growth in cool and cold regions, so the trees usually benefit from slight warming.

In addition, carbon dioxide – the dominant greenhouse gas warming Earth’s climate – is also the molecule that fuels photosynthesis in plants. As carbon dioxide concentrations in the atmosphere increase, plants carry out more photosynthesis and grow more.

More carbon dioxide is not automatically good for the planet – an idea often referred to as “global greening.” There are natural limits to how much photosynthesis plants can carry out. Plants need water and nutrients to grow, and supplies of these inputs are limited. And as carbon dioxide concentrations rise, plants’ ability to use it decreases – an effect known as carbon dioxide saturation.

For now, however, climate change has extended the growing season for trees in the Northeast by about 10-14 days. In my tree ring research, we routinely see trees putting on much more diameter growth now than in the past.

This effect is particularly evident in young trees, but we see it in old trees as well. That’s remarkable because old trees’ growth should be slowing down, not speeding up. Scientists in western states have even noted this acceleration in bristlecone pines that are over 4,000 years old – the oldest trees in the world.

Fall colors emerge when the growing season ends and trees stop photosynthesizing. The trees stop producing chlorophyll, the green pigment in their leaves, which absorbs energy from sunlight. This allows carotenoid (orange) and xanthophyll (yellow) pigments in the leaves to emerge. The leaves also produce a third pigment, anthocyanin, which creates red colors. A longer growing season may mean that fall colors emerge later – and it can also make those colors duller.

A changing mix of trees

Climate isn’t the only thing that affects fall colors. The types of tree species in a forest are an even bigger factor, and forest composition in the eastern U.S. has changed dramatically over the past century.

Notably, eastern forests today have more species such as red maple, black birch, tulip poplar and blackgum than they did in the early 20th century. These trees are shade-tolerant and typically grow in conditions that are neither extremely wet nor extremely dry. They also produce intense red and yellow displays in the fall.

This shift began in the 1930s, when federal agencies adopted policies that called for suppressing all wildfires quickly rather than letting some burn. At that time, much of the eastern U.S. was dominated by fire-adapted oak, pine and hickory. Without fires recurring once or twice a decade, these species fail to regenerate and ultimately decline, allowing more shade-tolerant, fire-sensitive trees like red maple to invade.

There is evidence that some tree species in the eastern U.S. are migrating to the north and west because of warming, increasing precipitation and fire suppression. This trend could affect fall colors as regions gain or lose particular species. In particular, studies indicate that the range of sugar maples – one of the best color-producing trees – is shifting northward into Canada.

Intensive logging and forest clearance across the eastern U.S. through the mid-1800s altered forests’ mix of tree species.

Forests under pressure

So far it’s clear that warming has caused a delay in peak colors for much of the East, ranging from a few days in Pennsylvania to as much as two weeks in New England. It’s not yet known whether this delay is making fall colors less intense or shorter-lasting.

But I’ve observed over the past 35 years that when very warm and wet weather extends into mid- and late October, leaves typically go from green to either dull colors or directly to brown, particularly if there is a sudden frost. This year there are few intense red leaves, which suggests that warmth has interfered with anthocyanin production. Some classic red producers, such as red maple and scarlet oak, are producing yellow leaves.

Other factors could also stress eastern forests. Climate scientists project that global warming will make tropical storms and hurricanes more intense and destructive, with higher rainfall rates. These storms could knock down trees, blow leaves off those left standing and reduce fall coloration.

Green leaves with brown-black spots.
Maple leaves infected with a fungal pathogen that can lead to premature leaf loss. UMass Amherst, CC BY-ND

Scientists also expect climate change to expand the ranges of insects that prey on trees, such as the emerald ash borer. And this year’s very wet fall has also increased problems with leaf-spotting fungi, which are hitting sugar maples particularly hard.

Forests shade the earth and absorb carbon dioxide. I am proud to see an increasing number of foresters getting involved in ecological forestry, an approach that focuses on ecosystem services that forests provide, such as storing carbon, filtering water and sheltering wildlife.

Foresters can help to slow climate change by revegetating open land, increasing forests’ biodiversity and using highly adaptable tree species that are long-lived, produce many seeds and migrate over time. Shaping eastern forests to thrive in a changing climate can help preserve their benefits – including fall color displays – well into the future.

Marc Abrams, Professor of Forest Ecology and Physiology, Penn State

This article is republished from The Conversation under a Creative Commons license. Read the original article.

PFAS: Navigating a new frontier in environmental regulation

Read the full story at JD Supra.

In recent years, states have begun investigating the health and environmental effects of PFAS and the class of chemical compounds that have come to be known as “forever chemicals.” This has led states to initiate massive efforts to remediate environmental media (primarily groundwater including municipal water sources) impacted by these chemicals, with many of these efforts focused on remediating drinking water supplies impacted by aqueous film-forming foams (AFFF) containing these chemicals. These efforts have also led states to initiate hundreds of lawsuits against PFAS manufacturers, seeking cleanup costs and other damages. As states have become more aggressive in their attempts to hold PFAS manufacturers and AFFF users responsible for impacts from these chemicals, including contamination of water supplies, it has become more important to understand the current state of regulation and litigation surrounding PFAS.

Graduate Women In Science (GWIS) National Fellowship Program

The Graduate Women In Science (GWIS) National Fellowship Program promotes knowledge in the natural and social sciences and encourages women’s academic and professional careers in the sciences. Endowment funds, mostly generated from bequests, provide the annual income that supports scientific research conducted by GWIS fellowship winners.

Application guidelines for the 2022-2023 Fellowship competition are now available. The deadline for all application materials, including letters of recommendation is Monday, January 10, 2022 at 5:00:00 pm Eastern Time.

Scientists design risk communication strategies to improve health

Read the full story at Environmental Health Perspectives.

By better understanding and connecting with communities, researchers can tailor messages, tools, and campaigns to effectively communicate environmental risks and improve public health, experts say. Building on their experience sharing such information with diverse groups, researchers from across the U.S. discussed successes, challenges, and recommendations during recent Risk e-Learning Webinars hosted by the NIEHS Superfund Research Program (SRP).

A quick guide to climate change jargon – what experts mean by mitigation, carbon neutral and 6 other key terms

Climate jargon can feel overwhelming. Illustration by Dennis Lan/USC, CC BY-ND

by Wändi Bruine de Bruin, USC Dornsife College of Letters, Arts and Sciences

As a major U.N. climate conference gets underway on Oct. 31, 2021, you’ll be hearing a lot of technical terms tossed around: mitigation, carbon neutral, sustainable development. The language can feel overwhelming.

“It sounds like you’re talking over people,” one person said of the terminology during a recent study colleagues and I conducted through the USC Dornsife Public Exchange.

Climate reports are often written at a scientific level. So we thought it would be helpful to clarify some of the most common terms.

To do that, we interviewed 20 people about common terms used by climate scientists and climate journalists. We then used their feedback to explain those terms in everyday language. With the help of the United Nations Foundation, we chose eight terms from reports written by the Intergovernmental Panel on Climate Change.

Here’s a guide that may help you to follow the news about climate change. The explanation of each term starts with the technical definition from the IPCC. The text that follows puts it into plain language.

1. Mitigation

IPCC definition: Mitigation (of climate change): a human intervention to reduce emissions or enhance the sinks of greenhouse gases.

Translation: Stopping climate change from getting worse.

When people talk about “mitigation” they often focus on fossil fuels – coal, oil and natural gas – used to make electricity and run cars, buses and planes. Fossil fuels produce greenhouse gases, including carbon dioxide. When these gases are released, they linger in the atmosphere. They then trap heat and warm the planet.

Some ways to mitigate climate change include using solar and wind power instead of coal-fired power plants; making buildings, appliances and vehicles more energy efficient so they use less electricity and fuel; and designing cities so people have to drive less. Protecting forests and planting trees also help because trees absorb greenhouse gases from the atmosphere and lock them away.

Rows of solar panels curve along a hillside with mountains in the background.
Use of solar power as an alternative to fossil fuels is growing. Gerard Julien/AFP via Getty Images

2. Adaptation

IPCC definition: In human systems, the process of adjustment to actual or expected climate and its effects, in order to moderate harm or exploit beneficial opportunities. In natural systems, the process of adjustment to actual climate and its effects; human intervention may facilitate adjustment to expected climate and its effects.

Translation: Making changes to live with the impacts of climate change.

Climate change is already happening. Heat waves, wildfires and floods are getting worse. People will have to find ways to live with these threats. Los Angeles, for example, is planting trees to help people stay cooler. Coastal cities like Miami may need sea walls to protect against floods. More “adaptation” actions will be needed as climate change gets worse.

3. Carbon dioxide removal

IPCC definition: Carbon dioxide removal methods refer to processes that remove CO2 from the atmosphere by either increasing biological sinks of CO2 or using chemical processes to directly bind CO2. CDR is classified as a special type of mitigation.

Translation: Taking carbon dioxide out of the air.

The amount of carbon dioxide in the air has been increasing for many years. In 2019, there was 50% more more of it than in the late 1700s. Planting trees and restoring grasslands can remove carbon dioxide from the air. There are also carbon dioxide removal technologies that store it underground or in concrete, but these are new and not widely used.

A machine with an intake and tubes behind two men talking.
Washington Gov. Jay Inslee discusses equipment that can remove carbon dioxide from the air. Gov. Jay Inslee/Flickr, CC BY-SA

4. Carbon neutral

IPCC definition: Carbon neutrality is achieved when anthropogenic CO2 emissions are balanced globally by anthropogenic carbon dioxide removals over a specified period. Carbon neutrality is also referred to as net-zero carbon dioxide emission.

Translation: Adding no net carbon dioxide into the air. This does not have to mean that you can’t add any carbon dioxide. It means that if you do add carbon dioxide into the air you take out the same amount.

The IPCC warns that the world needs to be carbon neutral by 2050 to avoid a serious climate crisis. This means using both “mitigation” to reduce the amount of carbon dioxide added to the air and “carbon dioxide removal” to take carbon dioxide out of the air.

5. Tipping point

IPCC definition: A level of change in system properties beyond which a system reorganizes, often abruptly, and does not return to the initial state even if the drivers of the change are abated. For the climate system, it refers to a critical threshold when global or regional climate changes from one stable state to another stable state.

Translation: When it is too late to stop effects of climate change.

One of the most talked-about tipping points involves the collapse of the West Antarctic ice sheet. Some research suggests it may have already started happening. West Antarctica alone holds enough ice to raise sea levels worldwide by about 11 feet (3.3 meters). If all glaciers and ice caps melt, sea levels will end up rising about 230 feet (70 meters).

Why the West Antarctic ice sheet may have passed a tipping point.

6. Unprecedented transition

IPCC definition for “transition”: The process of changing from one state or condition to another in a given period of time. Transition can be in individuals, firms, cities, regions and nations and can be based on incremental or transformative change.

Translation: Making big changes together to stop climate change – in a way that has not been seen before.

In 2015, countries around the world agreed to try to keep the planet from warming more than 1.5 degrees Celsius (2.7 F). Among the biggest sources of global warming are coal-fired power plants. Quickly shifting the world to renewable energy, such as wind and solar power, would be an unprecedented transition. Without big changes, climate change could make the world unlivable.

7. Sustainable development

IPCC definition: Development that meets the needs of the present without compromising the ability of future generations to meet their own needs and balances social, economic and environmental concerns.

Translation: Living in a way that is good for people alive today and for people in the future.

The United Nations has shared “sustainable development goals.” These goals aim to help countries grow in ways that are healthy for both people and the environment. Producing more carbon dioxide than the planet can manage is an example of unsustainable development that’s causing climate change.

A chart of CO2 concentrations based on ice core reconstructions and modern observations
Levels of carbon dioxide in the air have risen quickly over the past 70 years. NOAA

8. Abrupt change

IPCC definition: Abrupt climate change refers to a large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades and causes substantial disruptions in human and natural systems.

Translation: A change in climate that happens much faster than it normally would.

Our world is changing quickly as a result of climate change. Wildfires are raging in parts of the Western U.S. that were once too wet to burn. Coral reefs are dying as the ocean is getting warmer. These changes would not have happened so quickly – or at all – were it not for climate change.

Lance Ignon, a former communications adviser for the IPCC and now senior associate dean for strategic initiatives and communication at USC Dornsife and a co-author of the paper with Wändi Bruine de Bruin, Lila Rabinovich, Kate Weber Marianna Babboni and Monica Dean, contributed to this article.

This article was updated to correct the percentage to 50% more carbon dioxide than before the industrial era.

Wändi Bruine de Bruin, Provost Professor of Public Policy, Psychology and Behavioral Science, USC Price School of Public Policy, USC Dornsife College of Letters, Arts and Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Our planet is heating up. Why are climate politics still frozen?

Read the full story in the New Yorker.

Centuries after colonial and corporate powers set the stage for our environmental crisis, governments remain convinced that the market will solve it.

PFAS Central

PFAS Central provides current and curated information about PFAS, including press, peer-reviewed scientific articles, meetings, job listings, and consumer information.

Content is provided by a partnership between the Green Science Policy Institute and the Social Science Environmental Health Research Institute at Northeastern University. 

Air pollution in St. Louis helps fuel coronavirus spread, especially in communities of color

Read the full story from St. Louis Public Radio.

The coronavirus spreads faster in areas with poor air quality, according to new research from Washington University.

Researchers analyzed data on environmental, socioeconomic and health factors from a dozen U.S. cities, including St. Louis. They found that long-term exposure to microscopic air pollution and population density were both linked to faster coronavirus transmission — especially among communities of color.

Turning over a new leaf: the humble hedge stages a remarkable comeback

Read the full story in The Guardian.

Agriculture turns full-circle as the trend for ripping out hedges is reversed… and farmers hail the ecological benefits.

Information meetings set in 36 counties for second proposed carbon capture pipeline across Iowa

Read the full story in the Des Moines Register.

Texas-based Navigator CO2 Ventures will hold informational meetings about its proposed carbon capture pipeline with residents and landowners in three dozen Iowa counties beginning in November, the state utilities board said Wednesday.

Navigator CO2’s announcement of meetings on its carbon capture and sequestration project comes shortly after Summit Carbon Solutions concluded its series of meetings on a similar project.

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