Question

Explain why increasing concentrations of \(\mathrm{CO}_{2}\) in the atmosphere affect the quantity of energy leaving Earth but do not affect the quantity of energy entering from the Sun.

Short answer

In conclusion, increasing concentrations of CO2 in the atmosphere do not affect the quantity of energy entering Earth from the Sun because CO2 doesn't interact with shortwave solar radiation. However, it does affect the quantity of energy leaving Earth, as increased CO2 concentrations lead to a more significant absorption and re-emission of longwave infrared radiation emitted by the Earth's surface. This results in a stronger greenhouse effect, leading to an overall increase in Earth's temperature.

Step-by-step solution

Understand energy entering from the Sun

The energy entering from the Sun is primarily in the form of shortwave solar radiation. This radiation, mainly composed of visible light and ultraviolet light, can penetrate the Earth's atmosphere with little interference from greenhouse gases, as they generally don't absorb or interact with shortwave radiation.

Understand energy leaving Earth

The energy leaving Earth, on the other hand, is primarily in the form of longwave infrared radiation. This radiation, which is emitted by the Earth's surface as it radiates heat, is absorbed and re-emitted by greenhouse gases such as CO2. The more CO2 in the atmosphere, the more infrared radiation from Earth is absorbed, preventing it from escaping directly into space, thus increasing the greenhouse effect, which leads to a more significant warming of the Earth's surface.

Effect of increasing CO2 concentrations on energy entering from the Sun

As previously mentioned, CO2 does not significantly absorb or interact with shortwave solar radiation (mostly in the visible and ultraviolet range). Therefore, increasing CO2 concentrations in the atmosphere will not affect the quantity of energy entering Earth from the Sun.

Effect of increasing CO2 concentrations on energy leaving Earth

With increasing concentrations of CO2 in the atmosphere, the absorption of longwave infrared radiation emitted by the Earth's surface increases. This causes a reduction in the amount of energy directly escaping into space, as more energy is trapped within the atmosphere, enhancing the greenhouse effect. As a result, the Earth's surface temperature increases, and the overall energy balance of the Earth is affected. In conclusion:

Summary

Increasing concentrations of CO2 in the atmosphere do not affect the quantity of energy entering Earth from the Sun because CO2 doesn't interact with shortwave solar radiation. However, it does affect the quantity of energy leaving Earth, as increased CO2 concentrations lead to a more significant absorption and re-emission of longwave infrared radiation emitted by the Earth's surface. This results in a stronger greenhouse effect, leading to an overall increase in Earth's temperature.

Key concepts

Carbon Dioxide

Carbon dioxide (CO2) plays a significant role in the greenhouse effect, which directly impacts the Earth's climate. CO2 is one of several greenhouse gases present in the atmosphere.
It's essential in regulating Earth's temperature because of its interaction with longwave infrared radiation, emitted by the planet.
Unlike other gases that do not contribute to the greenhouse effect, CO2 and its peers are excellent at absorbing and re-emitting energy in the infrared spectrum.

• CO2 is transparent to sunlight, which means it does not absorb visible or ultraviolet light entering the atmosphere.
• However, it captures the warmth (longwave radiation) that radiates from the Earth's surface, which leads to heat retention within the atmosphere.
• As CO2 concentrations rise, this process intensifies, suppressing the heat from escaping back into space and raising the Earth's surface temperature.

Understanding CO2's role helps us grasp the importance of managing emissions to maintain the environmental balance.

Infrared Radiation

Infrared radiation is a type of electromagnetic radiation typically associated with heat. After the Earth absorbs sunlight, the surface releases energy, some of it as infrared radiation, which is crucial to understanding the energy dynamics within our atmosphere.
This longwave radiation differs from the shortwave solar radiation that enters our world from the sun.
Infrared radiation is pivotal for the greenhouse effect:

• It is this radiation that Earth's surface emits after absorbing the sun's energy.
• Greenhouse gases like CO2 absorb this energy and then re-emit it, often back towards the Earth's surface, attributing to the warming effect.
• While necessary for keeping Earth's climate at a stable temperature, increased levels of greenhouse gases can trap too much of this heat.

Understanding infrared radiation and its interaction with atmospheric gases is crucial to managing climate change.

Energy Balance

Energy balance refers to the equilibrium between the energy Earth receives from the sun and the energy it radiates back into space.
Normally, this balance maintains Earth's climate at a stable temperature, making it habitable for life.

• Incoming energy is primarily sunlight or shortwave radiation, which mostly passes unhindered through the atmosphere.
• The Earth then emits it as longwave infrared radiation. The balance is maintained when incoming solar energy equals outgoing terrestrial energy.
• However, increasing CO2 levels absorb more of this outgoing energy, trapping heat and altering this balance.

This disruption results in a warming effect, affecting climate patterns and contributing to global warming.

Atmospheric CO2

Atmospheric CO2 represents the concentration of carbon dioxide in the Earth's atmosphere. It is a chief contributor to the enhanced greenhouse effect and global warming. Rising atmospheric CO2 levels result from activities like burning fossil fuels, deforestation, and other industrial processes.

• Prior to the industrial age, atmospheric CO2 concentrations were stable, allowing for a relatively constant climate.
• Today, increased human activities have led to higher CO2 levels, accentuating the greenhouse effect and leading to climate change concerns.
• The monitoring of atmospheric CO2 provides critical data for climate science and informs policy decisions aimed at mitigating climate change impacts.

Understanding atmospheric CO2 levels helps us understand how human activity is affecting our planet’s climate and what measures might be necessary to reduce emissions.