Energy from the Sun is very important to the Earth. The Sun warms our planet, heating the surface, the oceans and the atmosphere. This energy to the atmosphere is one of the primary drivers our weather. Our climate is also strongly affected by the amount of solar radiation received at Earth. That amount changes based on the Earth’s albedo, that is how much radiation is reflected back from the Earth’s surface and clouds.
The amount of radiation given off by the Sun changes with solar activity like solar flares or sunspots. Solar activity is known to vary in cycles, like the 11-yr sunspot cycle (and longer cycles). Some scientists have wondered if changes in our weather and climate might be linked with short or long term solar cycles. Weather is the current atmospheric conditions, including temperature, rainfall, wind, and humidity for a given area, while climate is the general weather conditions over a longer amount of time. This has been an active area of research for decades. It is an example of the scientific process.
Some scientists tried to find a link between changes in Earth’s weather and solar variability. Although some scientists reported such correlations, later studies have not been able to find the same result, casting in doubt or disproving the original studies. Examples include studies of the relationship between the number of sunspots and changes in wind patterns, or between cosmic rays and clouds.
More researchers have looked at the influence of solar variation on Earth’s climate, again with mixed success. Changes in sunspot cycles do change the amount of solar radiation given off by the Sun, but only by a little bit. These changes aren't enough to account for the majority of the warming observed in the atmosphere over the last half of the 20th century. The only way that climate models can match the observed warming of the atmosphere is with the addition of greenhouse gases.