The ratio of stable carbon isotopes in climate proxies provides climate variable data

Climate proxies reveal past climate patterns using preserved natural evidence

Scientists use physical, chemical, and biological materials preserved in sediments, ice, and fossils to infer historical climate data. These proxies are studied and calibrated against modern climate conditions to interpret ancient environments accurately.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Carbon dioxide acts as a 'control knob' for Earth's climate

Although Earth's ice ages were primarily triggered by slow changes in the planet's orbit—known as Milankovitch cycles—these changes do not explain the extreme temperature swings during glacial periods. Carbon dioxide acts as a feedback mechanism, intensifying both cooling during ice ages and warming during their ends by reinforcing the initial changes sparked by orbital shifts.

Watch a time-lapse from space of photosynthesis across Earth

Using NASA satellite imagery, carbon absorption can be tracked and serves as a proxy for photosynthetic activity on land and in the oceans. Over the course of a year, seasonal changes can be observed as plants become dormant in the fall and active again in the spring.

Why the ratios of helium isotopes are analyzed to investigate ocean circulation

Volcanic activity on the seafloor produces high ratios of helium-3 to helium-4, which can be tracked in ocean samples more easily than other elements because helium is nonreactive. Water from deep ocean currents can also be distinguished from air-exposed surface water sources by comparing these ratios, since atmospheric helium ratios are much lower.

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.

Research shows Venus would be hotter if some of its CO₂ were swapped out

The planet's atmosphere—whose density is 92 times that of Earth's—is 96.5% carbon dioxide. Since these molecules all capture the same subset of infrared radiation emitted from Venus's surface, radiation outside this range escapes, demonstrating the increased impact that diverse greenhouse gas composition has on planetary warming.

Greenhouse gas concentrations can be measured using spectroscopy

Each type of greenhouse gas absorbs a distinct set of wavelengths of light, which serve as a unique spectral signature. By shining light through an atmospheric sample and measuring the light on the other side, the amount of each gas can be calculated from the amount of missing light.

View the 55 ECVs used to describe Earth's atmospheric conditions

Essential climate variables include physical, chemical, and biological variables that meaningfully contribute to Earth's climate and how it changes with time. Many of these variables influence one another through feedback mechanisms across Earth's atmosphere, hydrosphere, cryosphere, biosphere, and geosphere.

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.

What should you eat to help the climate?

Climate change is impacted by what we eat and what we don't eat. Did you know, for instance, that livestock accounts for 14.5 percent of the world’s greenhouse gases each year? Eating less meat and dairy and more protein-rich plants like beans,...

Radiometric dating uses radioactive isotopes to determine the age of objects

By comparing the amounts of parent and daughter isotopes and knowing how long it takes a sample of the former to become the latter, scientists can estimate when an organism was alive or when rocks formed.

How is the climate like baseball?

A two-minute video taking a lighthearted look at an unexpected analogy, explaining why some people call carbon dioxide (and the other greenhouse gases) the steroids of the climate system.

How greenhouse gases and climate change impact the efficiency of photosynthesis

A review in the Journal of Experimental Botany found that higher temperatures reduce the efficiency of enzymes involved in photosynthesis and impair a plant's ability to control water loss and regulate carbon dioxide uptake. While increased carbon dioxide levels are understood to accelerate plant growth by boosting photosynthesis, researchers suggest these effects more than offset the potential gain.

The three categories of photosynthesis, which each help plants survive in different environments

In the vast majority of plants, C3 photosynthesis produces three-carbon intermediate molecules in the Calvin cycle within the cells of leaves. Plants in hot, dry climates use C4 photosynthesis across two types of cells to produce four-carbon molecules before the Calvin cycle. Plants in drought conditions use CAM to store carbon dioxide as an acid at night, minimizing water loss.

Tree rings can reveal centuries of environmental change and natural events

The width and shape of tree rings reflect yearly growth conditions like rainfall or snowfall. Scars in the rings can record disruptions such as fires, avalanches, or earthquakes, explaining when and how those events occurred.

A look at Mauna Loa, which produces the gold standard of global CO2 measurements.

Mauna Loa Observatory is a station that measures the elements in the atmosphere that contribute to climate change. It is located on the side of the Mauna Loa volcano in Hawaii. 

How accurate are climate models?

RealClimate: A new paper from Hausfather and colleagues with the most comprehensive assessment of climate model projections since the 1970s. Bottom line? Once you correct for small errors in the projected forcings, they did remarkably well.

An explanation of isotopes, which can help scientists trace food, water, and farming choices

Atoms of the same element have the same number of protons, but experiments showed that atoms of the same element can move through electromagnetic fields as if they had different masses. These differences in mass come from variations in the number of neutrons, which contribute to the stability of atoms by providing a buffer to the repulsion between protons.

Questioning the results of life on K2-18b

An analysis of the atmosphere of an exoplanet called K2-18b identified the presence of biosignatures—molecules that are created by living things on Earth. This discovery may indicate life exists beyond Earth, but the lack of environmental data complicates the interpretation of results.

The origin of the symbiotic relationship between corals and the algae that feed them

An analysis of fossilized reefs from northern Africa and Germany suggests that shallow water corals and photosynthetic algae formed a mutualistic partnership between 419 and 359 million years ago. The discovery was made by analyzing nitrogen-isotope ratios in the fossils, which differ depending on whether algae are present, due to various chemical processes.

Despite privacy risks, scientists are using DNA in the air to assess ecosystem health

While DNA in soil and water samples has long been used for such analyses, airborne DNA is being incorporated into such efforts to monitor individual species abundance, detect invasive species, measure biodiversity, and determine the success of conservation actions. Future work may include detecting attacks from biological weapons.

Across a 20-year period, methane has more than 80 times the warming potential of CO₂

However, this greenhouse gas lasts only about 12 years in the atmosphere, much less than the centuries or more that carbon dioxide can persist. Methane is produced primarily during the production, storage, and transmission of coal, natural gas, and oil, as well as from the digestive processes of domestic livestock.

China's tree belt around the Taklamakan Desert has become a carbon sink

Decades of planting trees along the Taklamakan Desert in northwest China (the world's largest shifting-sand desert) have increased vegetation enough to create a measurable carbon sink, absorbing more carbon dioxide than the area emits. The effort demonstrates a key large-scale climate mitigation strategy, though it has raised concerns over water use and long-term sustainability.

Determine your carbon footprint with this web tool

This tool from the Environmental Protection Agency calculates a user's carbon footprint based on their zip code, household size, and emission factors involving home energy, transportation, and water production.

How one professor uses 'Walden' to study climate change

Richard Primack, a biology professor at Boston University, uses observations on Walden Pond's ecology from Henry David Thoreau's book to inform his study of climate change, noting that "Walden" is one of the oldest datasets available in the United States.

See how each of the more than two million known species relates to each other—and to common ancestors—in this zoomable tree of life.

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.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

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.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

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

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.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

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

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.

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.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by more than 1.5 million Muslims each year.

A small portion of The Winstons' 'Amen, Brother,' an obscure '60s gospel record, is the basis for thousands of hip-hop tracks, making it one of the most sampled records ever that's informally known as 'the Amen break.'

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.