Heat Budget and Climate Change

Heat Budget is the result of a balance between energy received (insolation and Earth’s Interior) and energy lost (terrestrial radiation) for an object. An object’s heat budget can be measured as an average temperature. Long term changes in the Earth’s Heat Budget can lead to climate change.

CLIMATE CHANGE

During Earth’s History, Earth’s heat budget has shifted between cooling and warming trends. Cooling trends have led to the advancement of glaciers in the middle latitudes. These cooling trends are referred to as ice ages.

Ice Ages and Warm Trends

CLIMATE CHANGE El Nino / La Nina.

Periodically the temperatures of ocean waters shift from cooler to warmer temperatures and vice versa. These temperature changes can lead to shifts in the heat budget.

CLIMATE CHANGE

Warm water influx off of the coast of South America In a La Nina event , exceptionally colder waters replace the cool water off of the coast of South America. This, in turn, leads to climatic change affecting the heat budget.

El Nino Every 2- 10 years the prevailing wind patterns shift in the Pacific Ocean pushing warmer water off of the west coast of South America – known for its cooler water. This influx of warm water can lead to a rise in temperature, air convection and precipitation for various locations around the Earth. The heat budget of the planet will change.

CLIMATE CHANGE

Global Warming In modern history, there has been a trend of rising average temperatures around the Earth. Much of Earth’s long-wave radiation is staying trapped in our atmosphere instead of escaping into space. Violent storms and heat waves are becoming more common due to global warming. As a result the heat budget for the planet is changing.

CAUSES FOR CHANGE IN HEAT BUDGET

A

sunspot

represents a darker region of the Sun’s surface. The presence and absence of sunspots in cyclical. When sunspots appear in large numbers, there is an increase in electromagnetic energy that reaches the Earth. This can cause an increase in the heat budget.

Change in Solar Energy

CAUSES FOR CHANGE IN HEAT BUDGET

Over periods of thousands of years the Earth’s tilt and its eccentricity in its orbit around the Sun changes slightly. This can alter the intensity and amount of insolation the Earth receives – thus, altering the heat budget for the planet.

When our orbit’s eccentricity AND tilt are altered at the same time; the climatic change is profound (Ex: increase in glaciation and the emergence of an Ice age) .

Change in Earth’s Orbit and Tilt

CAUSES FOR CHANGE IN HEAT BUDGET

Volcanic Eruptions

Some volcanic eruptions are quite intense and release a large amount of aerosols (volcanic ash, sulfur compounds, etc…) into the atmosphere. These aerosols remain in the atmosphere for some time – reflecting insolation from the Sun. Thus the heat budget for the planet will be altered. The Earth will be cooler.

CAUSES FOR CHANGE IN HEAT BUDGET

Human Causes

The activities of humans have led to changes in the planet’s heat budget.

Urbanization constructing of cities; increase in CO 2 =clearing of land for in atmosphere.

Deforestation = less insolation absorbed by plants; less precipitation.

Desertification = overgrazing of land leads to the spread of deserts; temperature increase.