In one of my previous article, I've discussed climate change, what causes it, it's effects and the evidences of its existence. Now I want to share to you two theories pointing to climate change. These are:
Milankovitch Theory
Sunspot Cycle
The first one, Milankovitch Theory states that as the Earth travels around the sun, cyclical variations of Earth-sun geometry combine to produce variations in the amount of solar energy that Earth receives. These cyclical variations include three elements which are: Earth's orbital eccentricity, Earth's axial inclination, and the direction of the Earth's axis of rotation. The Earth has a varying eccentricity, with a cycle of 100,000 years. Eccentricity measures the shape of the sun's orbit. High eccentricity at aphelion means less solar energy. Aphelion is the time when Earth is in its farthest point from the sun. Meanwhile, high eccentricity at perihelion means more solar energy. Perihelion as contrast to aphelion, is the time when the Earth is in its nearest point from the sun. There is a difference of about 6% amount of radiation during aphelion and perihelion. Earth reached its maximum eccentricity about 11,000 years ago or from the last ice age. At present time, Earth has an eccentricity of 0.017, with 0.07 as a maximum. It is a relative low eccentricity, which means that Earth is in an interglacial period, or simply a period of warming.
The second theory, is the Sunspot Cycle. Sunspots are regions where the temperature drops nearly 1500°C from the surface of the sun. They are first observed in 1610 by Galileo Galilei. It was determined by Astronomer Samuel Schwabe that sunspots have an 11-year cycle of waxing and waning, or in simpler terms, getting stronger and weaker respectively. Sunspots were recorded from 1645 to 1715 by which many regions of the planet experienced very low temperatures. Sunspots decrease the amount of solar radiation because they form areas where magnetic fields are strong that they are able to keep heat from reaching the surface of the Earth. Many weather events are associated with this solar activity such as the South Asian monsoons and local rainfalls around the world. It also affects climate as it influences solar emissions from the sun to Earth.
Sunspot regions are said to have spectral radiance which have a direct impact on climate and weather patterns as it affects certain layers of the atmosphere. Studies have shown that there is less amount of solar radiation when these sunspot regions are centered on what they called the solar disk. According to satellite data collected over several decades, there is a 0.1% change in solar radiation between the minimum and maximum periods of the sunspot cycle that has about 0.2 W/m² effect in the ocean surface, or in other words, a change in ocean temperature. Increased amount of radiation exposure in land can intensify weather events like monsoon and La Niña while increased solar radiation exposure in ocean regions could increase evaporation, higher temperature spike and higher moisture level that leads to more rainfall. The first sunspot cycle started at 1755 and at present time, it is now in cycle 24 and it reached its peak at year 2014.
As we can see, these are two relative theories of external forcings that suggest sensible changes in our climate system. While there is an increase in temperature, there is also noticable changes in solar activity of the sun that affects weather patterns. They may be two contradicting ideas because it suggests effects of warming and cooling, but their bottom line still, is our climate is indeed changing.
Link for my previous article about climate change below:
https://read.cash/@glossyberrycraze/lets-talk-about-earth-climate-change-ef82b2a3
Thank you for reading. ❤️
