The sun has no influence on the current global temperature increase, study says

When the red, glowing orb of the sun sinks into the sea

a

in the evening, it may provide peaceful and relaxed holiday moments. And even in the twilight we can still feel the cosy warmth delivered by the sun during the day. Yet, our star is anything but harmless. Not only does its UV radiation give some of our more careless contemporaries a serious sunburn. It is intrinsically extremely active, and parcels of hot plasma seethe constantly on the surface, injecting fountains of gas into space. Moreover, a wind of energetic particles constantly blows, occasionally freshening up to a storm, presenting a hazard to the sensitive electronics in satellites.

In addition to these routine phenomena, the radiant power of the sun is also subject to long-term fluctuations. These are caused by the solar magnetic field, the field lines of which are, as it were, "fused into" the electrically conductive gas. The strong turbulence rotates and twists the plasma tubes like rubber bands – which occasionally "snap" and then churn up the magnetic field.

These activities lead to phenomena such as dark spots or bright flares; the former are cooler regions, the latter regions with fibrous-looking bright spots and are hotter than their surroundings. The number of spots or flares is not always constant, but varies in an approximately eleven-year cycle. The total solar radiation intensity therefore also fluctuates in this period. These fluctuations average around 0.1 percent. However, the variations can also fluctuate – depending on wavelength, because the sun shines in numerous different bands of the spectrum. The ultraviolet radiation mentioned above, for example, which is particularly relevant with regard to the climate, varies by several tens of percents in the short wavelengths.

By way of its energy input, the sun can directly influence the climate of our planet. However, the atmosphere only allows radiation to pass through in specific wavelengths, predominantly in visible light; the remainder is, in a manner of speaking, absorbed by molecules. Only part of the radiation therefore reaches Earth's surface and can heat it up. The irradiated surface, in turn, emits infra-red light, which is then held back by clouds or aerosols. This effect, without which the Earth would be around 32 degrees Celsius colder, warms the atmosphere. These processes resemble the conditions in a greenhouse.

Read more at: https://phys.org/news/2017-08-sun-current-global-temperature.html#jCp