Talk:Are humans the main cause of global warming?

Anthropogenic global warming

The debate seems to be set up for anthropogenic global warming in particular, but the question itself doesn't reflect that — Preceding unsigned comment added by Phygleader (talk • contribs) 26 November 2016 (UTC)

Y Done --Felipe (discuss • contribs) 14:00, 13 April 2017 (UTC)

Sunspot cycle

The most extensive melting of polar ice caps occurred in 2005. The second most extensive melting of polar ice caps occurred in 2016. The sunspot cycle, the major one, has a period of 11.2 years. I can supply references to verify this, if interested. This suggests that humans are a secondary cause, not the primary one. --Marshallsumter (discuss • contribs) 16:05, 4 July 2017 (UTC)

@Marshallsumter: I'm definitely interested! I just added your argument, feel free to add the references when you want to. Cheers! --Felipe (discuss • contribs) 18:56, 4 July 2017 (UTC)

• I've started a section in solar cycles to try and summarize the influence of the solar cycle on global warming! More to be added! --Marshallsumter (discuss • contribs) 22:09, 6 July 2017 (UTC)

• Well, this is embarrassing! I went back through my news feeds to get the source for "The most extensive melting of polar ice caps occurred in 2005. The second most extensive melting of polar ice caps occurred in 2016." and can't find it! Sorry! What I have been finding is even weirder! Apparently, as reported "Observations show an increase in the rate of winter sea ice loss in the North Atlantic sector of the Arctic up until the late 1990s followed by a slowdown in more recent years. The observed trend over the period 2005 to 2015 is actually positive (a tendency for more ice)". So the statement may be true but no longer referenceable. Regarding the solar cycle influence, that is verified from a number of sources such as "Solar forcing [is] an important trigger for West Greenland sea-ice variability over the last millennium … Here, we use diatom assemblages from a marine sediment core collected from the West Greenland shelf to reconstruct changes in sea-ice cover over the last millennium. The proxy-based reconstruction demonstrates a generally strong link between changes in sea-ice cover and solar variability during the last millennium. Weaker (or stronger) solar forcing may result in the increase (or decrease) in sea-ice cover west of Greenland. In addition, model simulations show that variations in solar activity not only affect local sea-ice formation, but also control the sea-ice transport from the Arctic Ocean through a sea-ice–ocean–atmosphere feedback mechanism." --Marshallsumter (discuss • contribs) 15:32, 8 July 2017 (UTC)

• Here's an older study: The "approximately 80 year variability of the Koch [sea ice] index [has been compared] to the similar periodicity found in the solar cycle length, which is a measure of solar activity. A close correlation (R=0.67) of high significance (0.5 % probability of a chance occurrence) is found between the two patterns, suggesting a link from solar activity to the Arctic Ocean climate. … The 'low frequency oscillation' that dominated the ice export through the Fram Strait as well as the extension of the sea-ice in the Greenland Sea and Davis Strait in the twentieth century may therefore be regarded as part of a pattern that has existed through at least four centuries. The pattern is a natural feature, related to varying solar activity."

• Here's the really scary one from Forbes?! that I haven't found a counter to "Updated data from NASA satellite instruments reveal the Earth’s polar ice caps have not receded at all since the satellite instruments began measuring the ice caps in 1979. Since the end of 2012, moreover, total polar ice extent has largely remained above the post-1979 average. The updated data contradict one of the most frequently asserted global warming claims – that global warming is causing the polar ice caps to recede." Further, "Beginning in 2005, however, polar ice modestly receded for several years. By 2012, polar sea ice had receded by approximately 10 percent from 1979 measurements. (Total polar ice area – factoring in both sea and land ice – had receded by much less than 10 percent, but alarmists focused on the sea ice loss as “proof” of a global warming crisis.)" "In late 2012, however, polar ice dramatically rebounded and quickly surpassed the post-1979 average. Ever since, the polar ice caps have been at a greater average extent than the post-1979 mean."