Sunspot activity and climate

The sun is not a homogenous ball of energy, but has surface variations, called sunspots. There is an 11-year cycle during which sunspot activity goes up and down. At the moment, we are at a low spot.

This is more typical:

The area around a sunspot emits more energy, and this is one of the influences on global earth climate.

Various websites [e.g., here and here] have reported predictions that the current reduction in sunspot activity heralds a new ice age rather than global warming, and denialists are in glee about this.

Well, first let’s look at some of the evidence regarding the relative influences of solar activity vs. greenhouse gases.

I quote from “Hyperphysics” at Georgia State University: “While it appears that the measured solar cycle length tracks the temperature better than the CO2 concentration for the twentieth century up to 1970, this presented data remains quite controversial. When you look at the climate models that seek to show the human influence past 1970, you do see a good correlation of the temperature with the projected CO2 influence included, while the correlation with solar cycle length weakens.”

Let me translate into English: until 1970 or so, the solar cycle was a good predictor of global temperature variations. Since then, the amount of greenhouse gases in the atmosphere has overwhelmed this factor.

This set of graphs show the difference:

“The graphs show the raw data for temperature and solar activity at the top, then that data with a 11 year running average to filter out the normal solar activity period. The middle graph suggests a correlation between solar activity and temperature, even though the peaks are offset. But when the last few years of data are included, the curves diverge and severely weaken the case for the driving of temperature by this measure of solar activity. These illustrations were prepared by Chris Merchant, School of GeoSciences, University of Edinburgh from the original data.”

Science Daily states: “The sun’s impact on the climate is a matter of current debate, especially as regards the less-than-expected global warming of the past 15 years. There is still a lot of uncertainty as to how the sun affects the climate, but the study suggests that direct solar energy is not the most important factor, but rather [has] indirect effects on atmospheric circulation.”

Did we read it right? During the past 15 years, BEFORE solar spots went to sleep, there was LESS-THAN-EXPECTED GLOBAL WARMING? Thank heavens for that. I am sure all those millions of people devastated by extreme weather events are glad to know things should have been worse. I did some further reading to gain some understanding, and found an explanation by the Union of Concerned Scientists:

“The average increase in solar radiative forcing since 1750 is much smaller (~ 0.12 W m-2) than the increase in RF due to heat-trapping gases (~2.6 W m-2) over that same time period. The slight increase in solar absorption is, moreover, more than offset by natural cooling. The twentieth century witnessed the eruption of major volcanoes — the most recent, Pinatubo, in 1991– that spewed tiny reflective particles into the atmosphere. Incoming energy from the sun that encountered these particles was reflected back into space. In other words, natural processes alone would have brought about slight late twentieth century cooling — not the warming we have experienced.

“During the late twentieth century, the average amount of solar energy reaching the surface decreased slightly due to atmospheric particles (aerosols), particularly in urban locations, that reflect the sun’s energy back into space. This pollution did not cause net global cooling because it was more than counteracted by the increasing concentrations of heat-trapping gases in the atmosphere.”

So, I am sorry to be confident, but we are not going to have a new ice age. We’ll continue to see-saw toward self-destruction via cooking, not freezing. It is a see-saw, because climate is affected by a huge number of factors. We are just now on the tail-end of the greatest el Nino ever, which has been so large, and so damaging, because the oceans have been warming. When that eases off, global temperatures may rise slower. They may even fall. But the average will continue to rise. Same for the effects of solar activity.

But let us suppose, for the sake of argument, that the low count in sunspots does result in a significant temperature decrease. What are the implications?

The solar cycle is over 11 years. I am sure it’s not like clockwork, but has variations. Even if it is the lowest of the low, and lasts longer than expected, it is still a temporary state. Give it a few years, and it’ll climb again. In my essay How to predict disaster, I describe the Markovian random walk. A drunken man staggers along a mountain path, with a steep drop to the one side. Lowered sunspot activity is him staggering to the opposite side, toward safety — for now. But because he is staggering, he will soon step toward the other side. Luck has bought him a little time.

How should we spend this little time, if any?

By using the extra years, we may have a chance to ensure long term survival. By ensuring that WHEN the stagger goes the other way, the drunk won’t fall over the cliff. This means keeping fossil fuels in the ground, living as if the future mattered, replacing the greedy, unthinking striving for forever growth with living simply so we have a chance of simply living.

Besides, climate change is not actually the worst thing we have caused. Widespread species extinction is. All that carbon dioxide dissolved in the sea is contributing to the death of a great many species, together with plastic, overfishing, oil spills, Fukushima, and the runoff of fertilisers into the oceans. On land, cities, monocultural, toxic farming and forest clearing are killing nature.

It’s one of my cliches: when we unravel the web of life, we will fall through the hole.

Sunspots have nothing to do with this.