Is the Sun Causing Global Warming?


by David Wojick, Ph.D., blogging at CCDEDU

(May 27, 2019) — Some scientists argue that global warming is primarily due to natural variations in solar activity. Others think that global warming is primarily due to human activity, so there is a great debate over the sun’s role in global warming. Given that the sun warms the earth it is easy to see that changes in solar activity might cause global warming (or global cooling).

The sun is not constant. In fact it changes frequently and in many different ways. The debate is over whether any of these changes affect global temperature and if so how?

On the data side, there has sometimes been a strong correlation between indicators of solar activity, such as sunspots, and estimates of global temperature. This is the primary basis for thinking that changes in solar activity have caused some or all of the global warming. However, sometimes that correlation has not been strong, so the data is inconclusive. Additional data is being collected and this is a big research area.

On the physics side, the problem is that we can measure the changes in direct energy input from the sun, and these changes may not be large enough to explain the estimated global warming. Therefore, scientists are looking for other, indirect ways in which solar activity might change global temperatures.

The sun affects the earth in many ways besides simply providing direct energy, so a number of hypotheses have been proposed. This too is an active research area.

In the meantime, on the data side some of the indicators are changing in such a way that some scientists think that global cooling will now occur, not global warming. This too is now part of the scientific debate.

To see the recent science, try this Google Scholar search: “solar influence on climate change” research since 2018. There are almost 30,000 research papers, which show how active this research question really is. At this point we simply do not understand what role the sun may be playing in global warming.


My field is applied philosophy of science, especially with the climate change debate.

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