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You bring up a good point (the length of data). What the author says is: "Recent research (3) indicates that the combined effects of sunspot-induced changes in

You bring up a good point (the length of data). What the author says is: "Recent research (3) indicates that the combined effects of sunspot-induced changes in solar irradiance and increases in atmospheric greenhouse gases offer the best explanation yet for the observed rise in average global temperature over the last century." In answering the original commenter, I wanted to do research and see if the poster had a valid concern. I found nothing newer that ruled out sunspots as a contributor to warming. Maybe I missed something. However, I don't treat old research as less informative unless it has been disproven. I don't think that is the case here.

EForEndeavour 5y ago
It's true that more recent research further supports the above 1997 source's conclusion that sunspot cycles are a minor driver of global heating, and that human activity is the main cause of recent decades' rise in atmospheric CO2 concentration and the resulting rise in greenhouse warming and global mean temperature anomaly. One accessible summary of this that I posted elsewhere: https://www.climate.gov/news-features/climate-qa/couldnt-sun-be-cause-global-warming https://www.climate.gov/news-features/climate-qa/couldnt-sun... > there has been no significant net change in the Sun’s energy output from the late 1970s to the present, which is when we have observed the most rapid global warming > if the Sun’s energy output had intensified, we would expect all layers of Earth’s atmosphere to have warmed. But we don’t see that. Rather, satellites and observations from weather balloons show warming in the lower atmosphere (troposphere) and cooling in the upper stratosphere (stratosphere)—which is exactly what we would expect to see as a result of increasing greenhouse gases trapping heat in the lower atmosphere. Scientists regard this piece of evidence as one of several “smoking guns” linking today’s global warming to human-emitted, heat-trapping gases.

EForEndeavour 5y ago

It's true that more recent research further supports the above 1997 source's conclusion that sunspot cycles are a minor driver of global heating, and that human activity is the main cause of recent decades' rise in atmospheric CO2 concentration and the resulting rise in greenhouse warming and global mean temperature anomaly. One accessible summary of this that I posted elsewhere: https://www.climate.gov/news-features/climate-qa/couldnt-sun-be-cause-global-warming https://www.climate.gov/news-features/climate-qa/couldnt-sun... > there has been no significant net change in the Sun’s energy output from the late 1970s to the present, which is when we have observed the most rapid global warming > if the Sun’s energy output had intensified, we would expect all layers of Earth’s atmosphere to have warmed. But we don’t see that. Rather, satellites and observations from weather balloons show warming in the lower atmosphere (troposphere) and cooling in the upper stratosphere (stratosphere)—which is exactly what we would expect to see as a result of increasing greenhouse gases trapping heat in the lower atmosphere. Scientists regard this piece of evidence as one of several “smoking guns” linking today’s global warming to human-emitted, heat-trapping gases.