Greenhouse gas concentrations can be measured using spectroscopy

By separating light with tools such as prisms, scientists can reveal the presence and composition of celestial matter by identifying color fingerprints unique to specific elements and molecules.

Excluding water vapor, greenhouse gases make up less than 1% of Earth's atmosphere

Although carbon dioxide, methane, nitrous oxide, ozone, and most fluorinated gases account for only a minority of the planet's greenhouse effect due to their lower concentrations, they are more effective at trapping thermal radiation. While water vapor condenses within two weeks, other greenhouse gases linger in the atmosphere for years on average.

Watch a demonstration of the greenhouse effect with carbon dioxide, where thermal energy is trapped by the gas within a container, causing the temperature to increase.

Satellites can be used to measure photosynthetic activity worldwide by observing the red, biofluorescent light emitted by chlorophyll in plants.

Greenhouse gas removal consists of a series of techniques to capture and store GHGs

These include turning biomass into charcoal for storage in soil before it decays and releases carbon dioxide, crushing CO₂-absorbing rocks—increasing exposed surface area—and spreading them across land to accelerate GHG uptake, and restoring degraded peatlands, which can store twice the amount of carbon as the average forest.

Explore a simulation of the greenhouse effect

Investigate how cloud cover, surface albedo—a measure of a surface's reflectiveness—greenhouse concentrations, and atmospheric layers affect the energy balance on a simulated planet. Using either the wave or particle models of light, users can also explore how changes in solar intensity affect planetary surface temperature.

Yearly greenhouse gas emissions have been steadily increasing since 1850

Although greenhouse gases include methane, nitrous oxide, and most fluorinated compounds, their warming potential is often measured relative to carbon dioxide. In these units, greenhouse gas emissions have gone from 4.29 billion metric tons of carbon dioxide equivalent in 1850 to 54.43 billion metric tons in 2024.

The impact of greenhouse gases is assessed as a measure of Global Warming Potential

Since 1990, the Intergovernmental Panel on Climate Change has used GWP to measure how much energy 1 metric ton of a gas emits over a given period—usually 100 years—relative to 1 metric ton of carbon dioxide. By definition, carbon dioxide has a GWP of 1.

Methane: the other greenhouse gas

While most of the focus with respect to greenhouse gases lands on carbon dioxide, methane is the second most potent contributor. The gas, a carbon atom with four hydrogen atoms, is 25 times more potent than CO2 in terms of trapping heat over a 100...

Global CO2 levels as measured at Hawaii’s Mauna Loa Observatory, managed by the US government’s NOAA.

The Global Monitoring Laboratory conducts research on greenhouse gas and carbon cycle feedbacks, changes in clouds, aerosols, and surface radiation, and recovery of stratospheric ozone.

How geometry and uneven charge distribution make some molecules greenhouse gases

Molecules vibrate and rotate with different frequencies based on their elemental composition and shape, which can produce uneven distributions of electrons, as seen in carbon dioxide and water. The resulting unbalanced electric field can interact with electromagnetic waves of the same frequency, causing the molecule to absorb the radiation.

The greenhouse effect was discovered by analyzing Earth's temperature

Using mathematical techniques developed to analyze heat transfer, Jean-Baptiste Joseph Fourier showed that Earth should be significantly cooler if solar radiation were the only contributor to its surface temperature. By considering that the atmosphere could amplify the sun's warming effect, he formulated what became known as the greenhouse effect.

Greenhouse gas emissions from human activity accelerate recent global warming

These gases exacerbate the greenhouse effect—warming that results when the atmosphere traps heat radiating from Earth toward space. The most abundant atmospheric greenhouse gas is carbon dioxide, which is released from the burning of fossil fuels.

Nitrous oxide is the third most significant greenhouse gas made by human activities

Emissions of this molecule increased 40% from 1980 to 2020, with atmospheric concentrations reaching levels higher than at any other time in the last 800,000 years, based on ice core records. Its warming potential is 273 times that of carbon dioxide over 100 years and remains in the atmosphere for more than a century, on average.

Explore an interactive visualization of greenhouse gas emissions from 745 million sources worldwide.

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.

Validation of the greenhouse effect may have been misattributed

Although Irish physicist John Tyndall showed in 1859 that water vapor and carbon dioxide could absorb and radiate infrared radiation, experiments by American scientist Eunice Foote three years earlier identified the same phenomenon for light in general. Historically overshadowed, her work was rediscovered by female historians over a century later.

Exoplanet atmospheric gas patterns may indirectly provide evidence for life

When searching for life beyond the solar system, scientists first determine the range of distances from a star that liquid water—believed to be essential for life—can be found. Within this habitable zone, the presence of specific molecules in an exoplanet's atmosphere—detectable through spectral analysis—can indicate the presence of living things known to produce those compounds.

Climate data is monitored globally using tools from satellites to backyard gauges

Scientists use satellites, balloons, ocean buoys, and land-based instruments to track climate variables like temperature, precipitation, and wind. These tools gather data from deep ocean waters to the upper atmosphere.

Fluorinated molecules are the most impactful, longest-lasting greenhouse gases

Developed as replacements for ozone-depleting substances in refrigeration and air conditioning systems, these compounds are released through leaks in and ongoing use of these appliances, as well as from various industrial processes. They can remain in the atmosphere for thousands of years and have warming potentials that are a thousand to tens of thousands of times greater than those of carbon dioxide.

Carbon dioxide is the most produced greenhouse gas from human activities

In 2022, about 79.7% of US greenhouse gas emissions were carbon dioxide, produced through chemical reactions in processes such as cement production and the burning of fossil fuels, solid waste, trees, and other biological materials. Methane (11.1%), nitrous oxide (6.1%), fluorinated gases (3.1%), and trace amounts of solid and liquid aerosol were also created.

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.

Atmospheric greenhouse gases trap thermal energy and make Earth habitable

The moon and Earth are at the same distance from the sun, but the moon experiences large fluctuations in surface temperature because it lacks an atmosphere to insulate it. Gases such as water vapor, ozone, carbon dioxide, and methane can intercept about 90% of the infrared radiation emitted by Earth's surface.

View the transparency of Earth's atmosphere and how it blocks most forms of light

The gases that make up Earth's atmosphere block most harmful forms of electromagnetic radiation from reaching the planet's surface, except for some ultraviolet light. Their transparency to radio waves means this form of light can reach Earth's surface, which is why most radio telescopes are ground-based rather than space-based.

How Earth's 'greenhouse effect' works

The so-called "greenhouse effect," where various gases in Earth's atmosphere trap heat from the sun, is a crucial factor in our planet's ability to sustain life. It's also pivotal in discussions over humanity's impact on changes in the Earth's...

Scientists determine the smells of objects in outer space

Using spectrographic techniques, scientists determine the chemical composition of planetary atmospheres, comets, and other objects in space. Combining these chemicals in labs on Earth has revealed locations in space that smell like nail polish remover, rotten fish, and urine.

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.

How the pigments that absorb light for photosynthesis contribute to plants' green color

Although light energy is captured to power the reactions that produce the building blocks of starch, cellulose, glucose, and other sugars, chlorophyll a and b are most sensitive to violet, blue, orange, and red light, leaving green light mostly unabsorbed. This green light is instead reflected, giving most plants this color appearance.

In Raman spectroscopy, molecules use some of the energy from incoming light to shift into a more energetic vibration and scatter the remaining light, which scientists can use to confirm the molecule's presence.

How scientists determine elemental composition based on the light emitted by cooling atoms

When electrons within an atom drop to a lower energy level closer to the nucleus, they lose energy and produce light with energy equal to the difference between the two energy levels. Because these levels and the corresponding emitted light are unique to each element, the light serves as a unique signature that can be compared to known lab samples for identification.

Variations in the energy of light force the use of multiple telescopes

Just as Earth's atmosphere allows the sun's visible light to pass through while blocking other harmful radiation, telescope mirrors and other optics can only reflect, absorb, or transmit certain types of light. Detectors also utilize semiconducting materials that react to specific energies of light, thereby preventing a one-telescope-fits-all solution.

Virtually all plants are biofluorescent because their photosynthesis is powered by chlorophyll, a pigment that glows red as a way to get rid of excess energy when exposed to ultraviolet light.

By absorbing 90% of the thermal energy trapped by greenhouse gases, oceans are providing increasingly more energy to power the rapid strengthening of hurricanes.

The chlorophyll in plants captures energy in the form of red and blue light

Light-dependent reactions during photosynthesis convert sunlight into chemical energy, stored within the bonds of molecules such as ATP and NADPH. Rather than being absorbed for these reactions, most green light is reflected, causing most plants to appear green.

Explore which sectors produce the most greenhouse gas emissions by country

As of 2023, the energy sector, including electricity and heating, accounts for the largest share of greenhouse gas emissions. The 10 largest greenhouse gas-emitting nations account for two-thirds of global emissions, with the world's top three—China, the US, and India—contributing 15 times more than the bottom 100.

Carbon sinks absorb more greenhouse gases than they produce

The largest on Earth are oceans, which capture 25% of all carbon emissions and 90% of excess atmospheric thermal radiation while generating half of the world's oxygen. Wildfires and deforestation have reduced forests' net sink capacity, though fungi are believed to capture and store over a third of global carbon emissions.

Greenhouse gas emissions from human activities have contributed to global warming

A 2021 report from the Intergovernmental Panel on Climate Change found that such emissions were responsible for approximately 1.1 degrees Celsius (2.0 degrees Fahrenheit) of warming since 1850-1900. Without rapid, large-scale reductions in emissions, temperatures are expected to continue to rise, leading to more extreme weather events.

Without greenhouse gases, Earth's average surface temperature would be below freezing

Atmospheric molecules that absorb and emit infrared radiation from the planet's surface effectively trap additional incident solar energy that would otherwise escape to space. Without the greenhouse effect, the planet's average surface temperature would be approximately -18 degrees Celsius (0 degrees Fahrenheit).

Ozone protects against the sun's UV radiation and enhances the greenhouse effect

In the stratosphere, trioxygen molecules can absorb harmful ultraviolet radiation from the sun, preventing it from reaching Earth's surface, where it can harm organisms and raise surface temperatures. In the lower atmosphere, ozone acts as a greenhouse gas, trapping thermal radiation.

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.

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.

The food industry's hard-to-solve pollution

One-quarter of the world's greenhouse gas emissions result from food and agriculture. That whopping number includes production and post-farm processes like distribution. See a visualization of the data along with a breakdown explaining how each process contributes to emissions, and why it’s so difficult to improve the agriculture industry.

The Montreal Protocol helped prevent significant quantities of greenhouse gas emissions

By phasing out ozone-depleting chemicals between 1990 and 2010, the Montreal Protocol prevented emissions equal to 135 gigatons of CO₂—avoiding an estimated 0.5 to 1 degrees Celsius of additional global warming by 2100.

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. 

Greenhouse gases from farming are driven by meat

The food we eat contributes to one-third of global greenhouse gas emissions caused by human activities, according to two studies published in 2021. These emissions come from various sources along the food production chain, including transportation,...

Scientists use climate proxies—physical, chemical, and biological materials preserved in sediments, ice, and fossils—to infer historical climate data and determine past climate patterns.

Colorizers convert Hubble's gray scale images into color composites of different wavelengths

The near-infrared and ultraviolet light captured by the space telescope is not visible to human eyes, but observational data of these types of light can be filtered and modified into visible colors. Many detailed images of astronomical objects are the result of combining these artificially colored images into layers.

Arctic permafrost may store twice as much carbon as the entire atmosphere

Rising greenhouse gas concentrations are expected to continue to increase average global temperatures and threaten to thaw ground that has been frozen for thousands of years. The release of greenhouse gases from remnant organic matter would exacerbate the greenhouse effect, creating a positive feedback loop.

JWST might spot life faster on ocean worlds than Earth-like ones

Unlike Earth-like planets, hycean worlds with thick hydrogen atmospheres and deep oceans could allow biosignature gases like methyl halides to accumulate in detectable levels. These gases, linked to microbial life on Earth, are easier for the James Webb Space Telescope to identify than traditional markers like oxygen or methane.

The ocean's ability to store carbon long-term is being hindered by marine heatwaves

More than 4,000 robotic floats with biogeochemical data sensors, including oxygen, pH, nitrate, suspended particles, chlorophyll, temperature, and conductivity, have been deployed as part of the Global Ocean Biogeochemical Array. They have identified changes to ecosystem structure affecting the ocean's ability to transport carbon from surface waters into the deep.