Earth with Sun (bodies are not to scale). We all know the Sun provides Earth with light and warmth. It also provides energy that drives our weather. But how much influence do changes in the Sun have on the Earth's climate?
Click on image for full size
Courtesy of UCAR
Solar Cycle Variations and Effect on Earth's Climate
For more than 100 years, scientists have wondered if cycles on the Sun and changes of
the energy received at Earth because of those cycles affect
weather or
global climate on Earth. It is now thought that solar cycles on the Sun
don't affect weather, but that they do have a very slight effect on global climate.
The solar cycle is the rise and fall of the number of sunspots on the Sun. Solar activity is correlated to the number of sunspots on the Sun. As the number of sunspots goes up, solar activity occurrences go up.
Energy output from the Sun also changes as the sunspot count on the Sun changes. It is greatest when there are the most sunspots and lowest when there are the least sunspots. With satellite measurements, scientists have been able to confirm that the total solar energy varies 0.1% over one 11-year sunspot cycle. This variation of 0.1% means a global tropospheric temperature difference of 0.5oC to 1.0oC (1). These facts definitely have to be taken into account when dealing with climate models and predictions.
An example of when the solar cycle affected Earth's climate is the Maunder Minimum. This was when almost no sunspots were seen from about 1645 to 1715. During this time, Europe and parts of North America were struck by spells of really cold weather. This was a change to the expected regional climate.
So there does seem to be a connection between the solar cycle and climate - the very small change in solar energy that changes over the solar cycle seems to have a very small impact on Earth's climate (see IPCC report). Modern climate models take these relationships into account. The changes in solar energy are not big enough, however, to cause the large global temperature changes we've seen in the last 100 years. Indeed, the only way that climate models can match the recent observed warming of the atmosphere is with the addition of greenhouse gases.
Shop Windows to the Universe Science Store!
Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our
online store.
You might also be interested in:
Sunspots are dark, planet-sized regions that appear on the "surface" of the Sun. Sunspots are "dark" because they are colder than the areas around them. A large sunspot might have a temperature of about
...more
To figure out the future of climate change, scientists need tools to measure how Earth responds to change. Some of these tools are global climate models. Using models, scientists can better understand
...more
Over 100 years ago, people worldwide began burning more coal and oil for homes, factories, and transportation. Burning these fossil fuels releases carbon dioxide and other greenhouse gases into the atmosphere.
...more
Even though only a tiny amount of the gases in Earth’s atmosphere are greenhouse gases, they have a huge effect on climate. There are several different types of greenhouse gases. The major ones are carbon
...more
Some of the factors that have an affect on climate, like volcanic eruptions and changes in the amount of solar energy, are natural. Others, like the addition of greenhouse gases to the atmosphere, are
...more
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.
...more
Scientists at the National Center for Atmospheric Research (NCAR) have found a connection between solar activity and climate changes on earth. Their research may lead to the ability to predict how the
...more
