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

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.