It's Not the Sun

What We Know

The sun is not responsible for climate change. While there are some claims that increases in solar radiation are the cause of climate change, these are false. There are primarily two distinct ways scientists know that solar radiation levels are not the cause of climate change. The first way is by measuring the amount of solar radiation that has hit the upper atmosphere. Since 1978, scientists have found that there has been no increase in solar energy reaching the earth.

The second way is through the distribution of heat in the atmosphere. Because climate change is caused by trapping gases in the atmosphere, it is primarily warming the lower atmosphere. If the sun was responsible for climate change, then all layers of the atmosphere would be warming because the warming would be coming from above instead of below. Instead, only the lower atmosphere has experienced warming. The graph below from the National Oceanic and Atmospheric Administration (NOAA) shows how solar levels have not increased, while temperatures have.

This graph shows that while global temperatures have skyrocketed, solar energy has stayed in its typical 11-year cycle with a steady trend. The graph shows an 11-year average to demonstrate the overall trends. This is proof that solar energy is not the cause of climate change.

How We Know

Since the 1970s, scientists have used satellites to directly measure incoming sunlight levels. These satellites measure the total incoming sunlight at the top of the earth's atmosphere, before it is filtered through the atmosphere. These measurements ensure a complete understanding of how the sun's energy has changed. Scientists have used their research and knowledge of historical conditions to estimate solar levels since the 1600s.