Climate is abiotic, not biotic. In ecology, abiotic factors are the non-living parts of an environment, while biotic factors are the living organisms within it. Climate, made up of long-term patterns in temperature, rainfall, sunlight, and wind, falls squarely on the non-living side. It is, in fact, considered the single most important abiotic factor determining where land-based biomes exist and which species can survive in a given area.
What Makes Climate Abiotic
Biotic factors are living things: plants, animals, fungi, bacteria. Abiotic factors are the non-living conditions that surround them: water, soil, sunlight, temperature, atmosphere. Climate is a collection of these non-living conditions measured over decades, including average temperature, precipitation, humidity, and solar radiation. None of these components are alive, so climate is classified as abiotic.
Other abiotic factors you might see grouped alongside climate include soil composition, ocean salinity, water currents, and topography. Together, these non-living conditions create the physical stage on which all living things compete, reproduce, and evolve.
Why Climate Is the Key Abiotic Factor
Ecologists treat climate as the primary driver of biodiversity at large scales. When researchers model where species can live across regions or continents, they rely heavily on variables like mean temperature and precipitation. At these broad scales, climate consistently outweighs biotic factors like competition or predation in explaining species distribution. The productivity hypothesis, a well-established idea in ecology, holds that energy from sunlight and water availability are the main forces shaping how many species a region can support.
This is why you can predict what kind of ecosystem exists in a place just by knowing its climate. Hot and wet means tropical rainforest. Cold and dry means tundra. Moderate rainfall with warm summers means temperate grassland. Climate sets the boundaries, and living organisms fill in the details.
How Living Things Influence Climate Back
The classification of climate as abiotic doesn’t mean living organisms have no effect on it. Biotic factors can shape climate in significant ways, creating a two-way relationship.
Forests are the clearest example. Trees capture and store carbon, removing greenhouse gases from the atmosphere. They also influence local and regional climate through water and energy exchange: leaves release moisture into the air through evapotranspiration, and canopy cover changes how much solar energy the ground absorbs or reflects. Research published in Global Biogeochemical Cycles found that the effects of forest litter and understory carbon on regional climate regulation were as strong as the effects of temperature and precipitation interactions themselves. In other words, the biological structure of a forest matters just as much as the weather patterns around it when it comes to how that forest regulates climate.
At a local level, the effects are measurable and striking. Urban studies show that a 10% increase in vegetation cover can lower land surface temperatures by 1 to 2°C and raise air humidity by 5 to 10%. During extreme heat events, increased tree and grass coverage has reduced air temperatures by up to 1.5°C. Park areas in Riyadh, Saudi Arabia, measured surface temperatures 4 to 5°C lower than surrounding urban districts.
The Biggest Biotic Climate Shift in History
Perhaps the most dramatic example of life changing climate happened about 2.4 billion years ago during what scientists call the Great Oxygenation Event. Before this point, Earth’s atmosphere contained almost no oxygen, less than one hundred-thousandth of today’s levels. Cyanobacteria, tiny photosynthetic organisms living in ancient oceans, gradually pumped oxygen into the atmosphere as a byproduct of converting sunlight into energy. When these organisms became ecologically dominant over other microbes, oxygen levels surged to somewhere between 1 and 10% of modern levels.
This biotic event permanently transformed the planet’s atmosphere, its climate chemistry, and ultimately the trajectory of all life that followed. Iron stopped accumulating freely in oceans, new mineral formations appeared on land, and the atmospheric chemistry shifted in ways still recorded in rocks today. It’s a powerful reminder that while climate is classified as abiotic, biology and climate are deeply intertwined across Earth’s history.
Abiotic vs. Biotic at Different Scales
One useful way to think about the relationship: climate dominates at large scales, and biotic interactions dominate at small ones. If you’re asking why cacti live in deserts but not in swamps, the answer is climate. If you’re asking why one species of cactus thrives on a particular hillside while another doesn’t, the answer more likely involves competition with neighboring plants, soil microbes, or pollinator availability.
Traditional species distribution models reflect this split. They use climatic variables like temperature and precipitation to predict ranges across regions and continents, often without incorporating biotic factors at all. More recent research has pushed back on this approach, arguing that parasitism, predation, and competition matter even at broader scales. But the conventional framework remains: climate is the dominant abiotic force shaping life on Earth, and biotic factors fine-tune the picture locally.