The Sun and Climate Change
The recent warming of the climate is attributed to the incoming solar energy, but there are a few good arguments against this idea. First of all, there is no correlation between the irradiance of the sun and Earth’s temperature. That said, Skeptical Science and Bloomberg both have good explanations of the sun-earth relationship, and Skeptical Science provides an entertaining graphic. But what is the relationship between the sun and climate change?
Scientists estimate that the Sun’s luminosity has increased steadily over billions of years. The Sun will continue to increase in radiance, astronomers believe, by about 6% every billion years. The Earth will cease to support life at that rate within 1.1 billion years. In other words, the Sun will become so bright that life will no longer exist on Earth. As a matter of fact, stellar astronomers used to think that life on Earth would survive until it reached the red giant stage, but this is no longer the case.
The Sun’s energy output is steadily increasing over the past few billion years. Its energy levels have fluctuated by less than 1% during human history. The Sun has no engineers or regulatory committees and no safety check in place for nearly five billion years. In addition to the increased luminosity, the Sun is also accumulating more hydrogen into its core, which causes the core to become denser. The hotter the core gets, the brighter the Sun will be.
Solar radiation varies depending on latitude. The equator has the most solar energy, while high latitudes receive a lesser amount of solar energy. The equator gets the most energy, and the poles experience the most heat loss. The equator has greater net solar irradiance than the poles, but the opposite is true for the other two hemispheres. In general, the Earth’s temperature is at its highest during solar noon.
Earth’s atmosphere and surface absorb most of the solar radiation. It absorbs approximately 70% of the sunlight that reaches the planet, while the remaining 30% is reflected back into space. The planet also emits heat at longer wavelengths than the sun, so the energy absorbed by the Earth is reflected back into space, warming the atmosphere. Therefore, any disturbance to this energy balance will affect the climate. Even small changes in the energy output will result in a warm surface.
In addition to air pollution, the composition of the atmosphere can also affect solar heat. As the atmosphere warms, the concentration of water vapor increases, absorbing more solar radiation. The result is a pronounced greenhouse effect. Water vapor is responsible for increasing temperatures, and more water vapor means warmer weather. This is the main reason why we experience the warming of our planet. What’s more, it’s important to understand the reasons behind solar heating.
The radiation from the sun is the main source of energy for Earth’s climate. The amount of sunlight reaching the surface depends on latitude and season, while solar radiation is absorbed. The absorbed energy provides energy for processes in the atmosphere and hydrosphere. Changes in solar radiation affect the Earth’s climate and ecosystems. So, we must consider how much we can influence the sun’s temperature. And the factors that can affect it are the sun’s position in the sky and the amount of ozone in the atmosphere.
When the Sun’s temperature rises beyond normal levels, the nuclear furnace in the center of the star overheats. At this point, the star is less than a third of its original mass. That’s equivalent to 140 Jupiters! But as time goes on, the Sun will continue to increase in heat until it ceases to be a main-sequence star. In 7.1 billion years, it will be a dwarf star, shifting towards the upper right corner of the H-R diagram. It will begin to grow an electron-degenerate seed in the center of the Sun.
The Sun’s temperature is 5800 degrees Celsius, and the surface is a similar temperature. When facing the sun, we receive approximately 1,360 Watts per square meter of surface area. But when we face the Sun, that amount of energy rises to a higher level. This is known as insolation. However, not all solar energy reaches the earth. A large portion of it reaches the surface as visible light.