Poison ivy is projected to be larger and more resilient due to climate change

Scientists testing how climate change affected plants found in a years-long simulation study that poison ivy grew 70% faster than it did without extra carbon dioxide

The experiments in the 1990s were designed to simulate potential 2050 conditions, using carefully controlled circular forest plots with gas pumped into them.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it

Once sold as an ornamental plant, poison ivy can actually look varied—its colors change seasonally from reddish to green to yellow. It typically has three broad, shiny, tear-shaped leaves. But it sometimes may have a different number of leaves, and its edges can be serrated.

Poison ivy can cause rashes year-round since all parts of the plant contain urushiol, the oil that triggers our allergic response.

Urushiol, the oily toxin in poison ivy, can remain allergenic on clothing for years.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol.

Poison ivy can cause rashes any time of the year

This myth-busting article about poison ivy notes that all parts of the plant contain urushiol, the oil that triggers our allergic response, so if you are in the woods in winter you may be still encounter the plant—and urushiol.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

Urushiol, the oily toxin in poison ivy, can remain allergenic on clothing for years

The substance can still cause rashes even after being on shoelaces, clothing, sleeping bags, boots, or other clothing for multiple years—some reports say five years on surfaces—so they all need to be washed after outdoor adventures with the plants.

See if you know how to recognize poison ivy

This quiz, accompanied by photos of the varied forms of the plant, may help you identify the plant when it counts.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw, unprocessed state—but they are typically prepared in ways to avoid causing human discomfort.

Poison ivy's characteristic rash is caused by an allergic response to an oily compound in the plant called urushiol

Chinese lacquer tree sap also contains urushiol, yet the sap was widely used as a lacquer in Asian lacquerware for thousands of years. The word "urushiol" is derived from the Japanese word "usushi," which is the word for the lacquer tree.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

Poison ivy is in the same family as mangoes, cashews, and pistachios—and they all produce oily urushiol in their raw unprocessed state, and chewing mango skin can produce blister rashes

Poison ivy only seems to lead to allergic responses in humans, other primates, and guinea pigs. Other animals can both interact with the plant and eat it without becoming sickened.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity

The plants were grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Increases in atmospheric carbon dioxide lead plants to produce more pollen

Pollen issues are emerging earlier in the year and lasting longer as rising levels of carbon dioxide in the atmosphere boost plants’ pollen production and also simultaneously extend warmer, pollen-producing seasons.

Plants use physical and chemical defenses to protect themselves

Tree bark is difficult to chew and resistant to pathogens, while the waxy cuticle on the surface of leaves deters insects and microbes. Some plants possess thorns, spines, and prickles to discourage predators. Plant cells can also produce antimicrobial toxins or release compounds to alert parasitic wasps to lay eggs in attacking insects.

The ‘humongous fungus’ may be the largest organism on Earth at more than 2,300 acres

Discovered in 1988, when it was only covering 400 acres, this massive colony of Armillaria ostoyae, based in Oregon, has taken hold among the tree roots of the Malheur National Forest. It consists of a vast network of unique long black filaments of fungal tissue called rhizomorphs that grow under the soil and infect tree roots, nourishing the fungus but killing the trees. Researchers believe this fungal growth dates back more than 8,000 years and currently weighs approximately 35,000 tons.

Seasonal allergies don't always show up in childhood

The human immune system may become sensitized to pollen and develop an allergic reaction to it after prolonged exposure. Other triggers for new seasonal allergies may include exposure to new environments and changing climate conditions that affect allergy season length and conditions for various pollens.

A Death Valley shrub optimizes its cells' organelles to photosynthesize in extreme heat

Examining the cellular structure of the plant under heat, scientists observed the formation of novel, cup-shaped chloroplasts and mitochondrial relocation, which shifted the plant's optimal photosynthesis temperature to 45 degrees Celsius (113 degrees Fahrenheit) as it tripled in mass over 10 days. Engineering these mechanisms in crops may help optimize them for hotter environments.

The fragility of the alpine tundra

This article takes readers into Rocky Mountain National Park's Alpine Tundra, an area above the tree line where only specially adapted plants can survive. One such plant is the cushion plant, which avoids strong winds by growing close to the ground...

Most fungal pathogens can't survive the heat of our bodies

Fungal pathogens typically struggle to survive human body temperatures, but researchers hypothesize that global warming conditions will force fungi to adapt to hotter temperatures, with implications for their ability to also survive within our bodies. That type of evolutionary adaptation would lead to more dire health threats for humans.

Human activities release 100 times the carbon dioxide of all volcanic eruptions

While gases released by volcanoes contribute to climate change, humans produce the carbon dioxide equivalent of a Mount St. Helens-sized eruption every 2.5 hours, or more than one Yellowstone eruption yearly, even though such supervolcanoes only erupt about every 100,000 to 200,000 years or more.

Why Earth would become a more deadly environment without the ozone layer

The ozone layer blocks almost all of the sun's harmful, including dangerous UVC rays that can damage cells by breaking chemical bonds. Without it, rates of skin cancer, crop failures, oceanic die-offs, and widespread ecosystem collapse would increase significantly, making Earth largely uninhabitable.

Invasive species can harm infrastructure and threaten human health

The wildfires in Hawaii in 2022 were made worse by flammable invasive grasses introduced from Africa as livestock pasture, and Zebra mussels native to the Caspian and Black Seas have spread across Europe and the US, where they can clog power plant pipes. Invasive mosquitoes can carry diseases, such as dengue and malaria.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Wildfires have seriously affected Napa's winemaking

If there’s a single thing that has defined the last decade of California winemaking, it’s the effects of climate change, particularly wildfires. To avoid the threats of wildfires, some vineyards have pivoted to more heat-tolerant grapes.

Aerial photos of red tide off the Gulf Coast

The toxic algae grows naturally in warmer oceans in small amounts and is typically harmless. With extended warm periods and unusually-high additions of nutrients from run-off, the algae blooms extensively, posing health risks to wildlife and humans...

Large animals like giraffes and elephants have evolved unique cancer defenses

One may expect the larger an animal is, the more likely it is to develop cancer—simply because there are more cells and more chances for a dangerous mutation. However, some large animals show cancer rates almost 10 times lower than humans—a phenomenon known as Peto's Paradox.

Land use changes in Connecticut may have helped to enable Lyme's leap into humans

Forest clearing and fragmentation, alongside suburban development, may have contributed to the emergence of Lyme disease in humans in the 1970s. Those changes brought mice, carriers of the disease, into greater contact with people. Climate change is also facilitating Lyme's spread as tick populations survive milder winters and move northward.

The legacy of Agent Orange: a photo gallery

An herbicide sprayed over the Vietnamese jungles during the war had a far greater impact than its supposed role as a defoliant, a chemical used to remove greenery. Agent Orange’s deleterious nature quickly impacted exposed people – and their children. This photo gallery, which includes graphic images, follows a photographer as they report on those affected by the chemical.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

The girl who lived in a tree for years

Julia Butterfly Hill lived in a redwood tree outside Stafford, California, for two years to prevent a lumber company from cutting it down, subsisting on rainwater and other provisions hoisted up by other volunteers.

Porcupines, when threatened, go piloerect—essentially, they get goose bumps

If stressed, the animal appears to grow to about twice its normal size because it goes piloerect, which causes the quills to stand erect. If this intimidation tactic to avoid conflict doesn't work on the predator, the animal may get stabbed by the quills upon contact with the porcupine.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Fireworks-related ER visits are on the rise—in 2024, they increased by 52% as compared to the prior year.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

Art theft is the third-largest source of criminal revenues worldwide, thanks in part to the subjective nature of valuing a work of art.

US consumers collectively owe more than $1T to credit card companies—almost as much as they owe in auto loans.