When first thinking about land masses and climate, it makes sense to remember the wisdom of real estate agents: think location, location, location! The effects of land on the atmosphere and its energy balance depend on the location of the land mass on the globe, especially its latitude—how far north or south it is from the equator. At the equator, the Sun’s rays strike the surface of Earth at right angles (90°) and the energy is concentrated. Land at higher latitudes receives less concentrated solar radiation due to the smaller angle at which the Sun’s rays arrive at the surface. This makes their climates generally cooler than land near the equator.

Whether a land mass is located in the Northern Hemisphere or the Southern Hemisphere also affects its climate. The Southern Hemisphere has more ocean area than the North, and ocean water stores large quantities of heat. As a result, climate conditions over land in the Southern Hemisphere may be more moderate than similar latitudes in the Northern Hemisphere.

An increase in the elevation, or altitude, of a land mass also makes for a cooler climate. Increases in altitude mean thinner air, which makes the atmosphere less able to absorb and retain heat. There are other important climate factors besides location. Surface properties of land masses play a role in how land and climate influence each other. Properties such as surface reflectivity, or albedo, roughness, water-holding capacity, and plant life all affect surface temperatures across a land mass. Surfaces with high albedo, often caused by snow or ice, reflect more sunlight energy than dark surfaces—a cooling influence on climate. The removal of forests, deforestation, increases soil temperatures by exposing soils to sunlight which increases their release of carbon dioxide—a greenhouse gas and a warming influence on climate.

Changes to the land surface also affect how water moves, and whether it evaporates from the soil surface, drains through the soil, or is absorbed by the roots of plants. This is called surface water balance, and affects local humidity. This affects local climate, since moist air retains heat longer than dry air.

Changes to the carbon cycle or the nitrogen cycle caused by human activities such as burning forests or using nitrogen fertilizers also affect climate conditions.

As scientists increase their ability to monitor land masses, especially by using data from satellites, they will improve their understanding of the role that land plays in Earth's climate system.

Print Background Essay