The Sun’s low activity has once been linked to global cooling, but warming is now the dominant factor.
A frequent resource in the arsenal of skeptics against global warming is to recall that, some 50 years ago, the popular idea regarding climate change was that the world was getting colder not warmer. An article about the Global Cooling in the magazine Newsweek and a presumed cover of Time -denied as a montage by the publication itself- serve deniers to argue that climate science says one thing and the opposite. But historical storms such as the Filomena storm revive the debate these days: and If we’re heading into a new Ice Age?
The truth is that the planet has gone through cyclical glaciations: the ‘Little Ice Age’ barely dates back a few centuries, from 1650 to 1715 in the Northern Hemisphere according to NASA. It was the time when Londoners held fairs and skated on the frozen Thames, and it coincided with an astronomical phenomenon: a Great Solar Minimum, a period of low activity of the Sun, poor in flares and sunspots, which is precisely reproducing in these moments. These solar cycles tend to go from Maximum to Minimum in periods of 11 years, but another of the unfortunate legacies of 2020 is that the lethargy of the star king is not recovering as expected.
If the Great Solar Minimum caused a glaciation before the human hand began to affect the climate, at the time of the Enlightenment, should not its effects be taken into account now? It is a minority theory among climate scientists themselves, who even propose, if not a ‘new Ice Age’, at least a ‘compensation effect’ that helps meet the objective set by the Paris Agreement of limiting the increase in temperatures at 1.5ºC. But the truth is yes there was environmental pollution at that time, the result of volcanism: Particles projected into the atmosphere blocked solar radiation, causing cooling.
This is the phenomenon that led the media to talk about ‘Global Cooling’ in the seventies: as Professor James Renwick explains in The Conversation, in that decade the emission of CO2 and polluting gases was in full expansion and had the short-term effect of blocking solar radiation, with the consequent drop in temperatures. It is in the following decade when the accumulation of pollutants triggered effects such as the anthropogenic greenhouse effect and the hole in the ozone layer.
Any variation in the solar cycles pales in the face of the climate crisis that is currently plaguing the Earth, says NASA: “The warming caused by greenhouse gas emissions produced by the burning of fossil fuels by human beings is six times greater than any possible cooling caused by a Grand Solar Minimum“. “Even if this Grand Solar Minimum lasted a century, global temperatures would continue to rise,” continues the Space Agency.
“The reason is that there are many factors that influence temperature variations on Earth that go beyond solar cycles, and the most dominant of them all is the emission of greenhouse gases by humans.” Professor Renwick adds that accumulations of carbon dioxide will be with us for “thousands of years”, so in fact “the next Ice Age has been postponed for a long time”.
If the unequivocal trend is towards warming, why are there effects of extreme cold and unprecedented snowfalls such as that caused by Filomena? This question was addressed in a previous article: rising temperatures at the poles push storms with arctic air to lower latitudes than they would normally reach. The forecast is therefore an accentuation of the extremes: increasingly warm years with occasional winter episodes that are increasingly harsh.