New! Sign up for our free email newsletter.
Reference Terms
from Wikipedia, the free encyclopedia

Greenhouse effect

The greenhouse effect is the process in which the emission of infrared radiation by the atmosphere warms a planet's surface. The name comes from an analogy with the warming of air inside a greenhouse compared to the air outside the greenhouse. The Earth's average surface temperature is about 33°C warmer than it would be without the greenhouse effect. In addition to the Earth, Mars and especially Venus have greenhouse effects.

The Earth receives energy from the Sun in the form of radiation. The Earth reflects about 30% of the incoming solar radiation. The remaining 70% is absorbed, warming the land, atmosphere and oceans. For the Earth's temperature to be in steady state so that the Earth does not rapidly heat or cool, this absorbed solar radiation must be very nearly balanced by energy radiated back to space in the infrared wavelengths. Since the intensity of infrared radiation increases with increasing temperature, one can think of the Earth's temperature as being determined by the infrared flux needed to balance the absorbed solar flux. The visible solar radiation mostly heats the surface, not the atmosphere, whereas most of the infrared radiation escaping to space is emitted from the upper atmosphere, not the surface. The infrared photons emitted by the surface are mostly absorbed in the atmosphere by greenhouse gases and clouds and do not escape directly to space.

The reason this warms the surface is most easily understood by starting with a simplified model of a purely radiative greenhouse effect that ignores energy transfer in the atmosphere by convection (sensible heat transport) and by the evaporation and condensation of water vapor (latent heat transport). In this purely radiative case, one can think of the atmosphere as emitting infrared radiation both upwards and downwards. The upward infrared flux emitted by the surface must balance not only the absorbed solar flux but also this downward infrared flux emitted by the atmosphere. The surface temperature will rise until it generates thermal radiation equivalent to the sum of the incoming solar and infrared radiation.

Related Stories
 


Earth & Climate News

October 8, 2025

The Amazon has suffered its most destructive fire season in more than two decades, releasing a staggering 791 million tons of carbon dioxide—on par with Germany’s annual emissions. Scientists found that for the first time, fire-driven ...
Researchers at KAUST have confirmed that the Red Sea once vanished entirely, turning into a barren salt desert before being suddenly flooded by waters from the Indian Ocean. The flood carved deep channels and restored marine life in less than ...
Marine heatwaves can jam the ocean’s natural carbon conveyor belt, preventing carbon from reaching the deep sea. Researchers studying two major heatwaves in the Gulf of Alaska found that plankton shifts caused carbon to build up near the surface ...
Solar energy is now the cheapest source of power worldwide, driving a massive shift toward renewables. Falling battery prices and innovations in solar materials are making clean energy more reliable than ever. Yet, grid congestion and integration ...
New research reveals that deep-sea mining could dramatically threaten 30 species of sharks, rays, and ghost sharks whose habitats overlap with proposed mining zones. Many of these species, already at risk of extinction, could face increased dangers ...
Billions of years ago, Earth’s atmosphere was hostile, with barely any oxygen and toxic conditions for life. Researchers from the Earth-Life Science Institute studied Japan’s iron-rich hot springs, which mimic the ancient oceans, to uncover how ...
In 2020, California’s Creek Fire became so intense that it generated its own thunderstorm, a phenomenon called a pyrocumulonimbus cloud. For years, scientists struggled to replicate these explosive fire-born storms in climate models, leaving major ...
Swiss glaciers lost nearly 3% of their volume in 2025, following a snow-poor winter and scorching summer heatwaves. The melt has been so extreme that some glaciers lost more than two meters of ice thickness in a single season. Scientists caution ...
Fungi may have shaped Earth’s landscapes long before plants appeared. By combining rare gene transfers with fossil evidence, researchers have traced fungal origins back nearly a billion years earlier than expected. These ancient fungi may have ...
Scientists have uncovered an unexpected witness to Earth’s distant past: tiny iron oxide stones called ooids. These mineral snowballs lock away traces of ancient carbon, revealing that oceans between 1,000 and 541 million years ago held far less ...
Scientists found that biochar doesn’t just capture pollutants, it actively destroys them using direct electron transfer. This newly recognized ability accounts for up to 40% of its cleaning power and remains effective through repeated use. The ...
Bio-tar, once seen as a toxic waste, can be transformed into bio-carbon with applications in clean energy and environmental protection. This innovation could reduce emissions, create profits, and solve a major bioenergy industry ...

Latest Headlines

updated 12:56 pm ET