The temperature of the sun rises


Is the change in the sun's surface temperature responsible for global warming?


The global climate on earth is determined by many factors: the radiant power of the sun, the inclination of the earth's axis, the distance between the sun and the earth, the proportion of sunlight reflected back into space, the volcanic activity and the suspended particles in the atmosphere, the proportion the so-called greenhouse gases in the atmosphere and much more.

The radiation of the sun on the earth is, averaged over the entire surface of the earth, about 342 watts per square meter. Of this, 30 percent is reflected back directly into space, leaving 240 watts per square meter. This would mean that the earth would warm to a very low -18 degrees Celsius on average. The earth heated in this way radiates heat in the infrared spectral range into space. Part of this thermal radiation is swallowed up by the greenhouse gases, especially carbon dioxide and water vapor, and partly reflected back to the earth. This “natural” greenhouse effect gives us an average of a pleasant 15 degrees Celsius.

The global temperature on earth is currently increasing. In the past 100 years it has become one degree warmer on average. The increase has been particularly dramatic since 1980. But what is causing the warming? Could the sun and its radiation be responsible or is it the increase in carbon dioxide in the earth's atmosphere and thus the greenhouse effect?

In fact, the sun's brightness fluctuates. The magnetic activity of the sun is responsible for the changes in brightness over a period of decades to centuries. The number of dark sunspots and bright sun flares fluctuates every eleven years. This also causes a change in brightness, which is only about one per thousand and has been measured by satellites since 1978. These fluctuations are too small and too fast to have any impact on the climate.

A number of scientists are currently reconstructing the brightness of the sun over the past 150 years, the past 400 years, and even further back in time. Long-term trends and larger differences can be seen and there are connections with the global climate on earth, which is also traced back to the past. In this respect, the sun apparently contributes to the climate on earth.

Solar activity has been about constant on average since 1940, and has even declined slightly over the past few decades. However, the temperature on earth has been rising rapidly since 1980. The sun is not responsible for this. It is very likely that the warming is due to increases in carbon dioxide and other greenhouse gases in the atmosphere. Carbon dioxide is produced when fossil materials are burned and is increasingly being released into the atmosphere by humans. This increases the greenhouse effect and the earth warms up.