Bob Henson, Weather Underground Blog
If you’re looking toward the sun to help explain this decade’s record global heat on Earth, look again. Solar activity has been below average for more than a decade, and the pattern appears set to continue, according to several top solar researchers. Solar Cycle 24, the one that will wrap up in the late 2010s, was the least active in more than a century. We now have outlooks for Cycle 25, the one that will prevail during the 2020s, and they’re calling for a cycle only about as strong as–and perhaps even less active than–Cycle 24.
While Henson tries to make the case that sunspots have little influence on the climate, citing Solar Cycle 24 low sunspot intensity, while planet experience rising global temperatures.
Newly precise measurements confirm that the total solar energy reaching Earth actually doesn’t change all that much from cycle to cycle. As a single cycle ramps up from minimum to maximum, the sun spits out as much as 10 times more energy in extreme ultraviolet wavelengths. However, the sun’s total energy output (irradiance) goes up by a mere 0.1% during a solar cycle, and this boosts global surface temperature by no more than 0.1°C per cycle, according to the Intergovernmental Panel on Climate Change.
Bolstering his argument with a chart from skepticalscience.com which seems to ignore the 20-year global warming pause in the satellite temperature measurements. I will leave that discussion for another time but it seems to me that the pause and a low solar cycle may have some connection. Moving on to more interest items in Bob Henson’s post, the future of Solar Cycle 25.
Outlook for the 2020s: Another modest cycle
The community of solar researchers has only recently come into consensus on the “polar predictor” method of using polar magnetic fields as the best predictor of solar cycles. A decade ago, various methods produced conflicting results on how strong Cycle 24 would end up. Forecasts based on polar fields at solar minimum did remarkably well; others had more trouble in capturing the cycle’s length and strength. “One of the things we learned is that the difference between the hemispheres is critical,” said McIntosh. The north half of the sun ran about two years ahead of the south during Cycle 24, and that overlap led to the double-peaked maximum (2011 and 2014) while lessening the cycle’s overall peak strength.
Researchers are now trying to push the limits of prediction further. They’re using statistical and dynamical models, plus some data-based intuition, to predict several years in advance how the subsurface magnetic fields will look when they emerge near the poles around 2020, and what, in turn, those fields may tell us about Cycle 25.
• David Hathaway (recently retired from NASA) and Lisa Upton (NCAR and Space Systems Research Corporation) expect a Cycle 25 about as strong as Cycle 24, or perhaps slightly weaker. They published their outlook in November in the Journal of Geophysical Research. Hathaway and Upton used an ensemble model to project the polar fields from now to the end of 2019, with the ensemble showing an uncertainty by that point of about 15%. Natural solar variations in the early 2020s could add to the uncertainty, they note.
• Leif Svalgaard (Stanford University) pioneered the idea of using solar polar fields as prediction tools with colleagues in the 1970s, and he successfully pegged the eventual weakness of Cycle 24 back in 2005. Svalgaard is calling for a weak Cycle 25, but perhaps just a bit stronger than Cycle 24, based on precursors that appear slightly more active this time around.
• NCAR’s McIntosh believes Cycle 25 could extend the recent string of progressively weaker cycles. “We anticipate that the growing degree of overlap between cycles means that Cycle 25 will be weaker than Cycle 24,” he told me.
• Also at NCAR, Mausumi Dikpati will release her outlook for Cycle 25 in a paper to be published later this year. Dikpati and colleagues predicted a stronger-than-average Cycle 24 (as did Hathaway and others). This didn’t materialize, but Dikpati did correctly forecast that Cycle 24 would begin later than usual. Dikpati is now doing a post-mortem on her Cycle 24 forecast, which was based on a pioneering model of the solar dynamo (the flow of plasma that produces magnetism within the sun). As with weather models, she expects that improved data assimilation–bringing the latest observations into the solar dynamo model–will help boost its accuracy.
With several decades of quiet solar activity, we will be experiencing a “Grand Minimum.” The open question is will this Grand Minimum produce a cooler plant, similar to the Dalton Minimum or the Maunder Minimum which is associate with the little ice age. Only time will tell. Your thoughts?
Bob Henson’s full post is HERE. It also includes an interesting discussion of the threat from solar eruptions to our electrical grid, even during a grand minimum.
If the ordinary citizen is to realistically assess the true impact of solar variability on earthly climate, to make some kind of sense of the ifs, whethers and suppositions, perhaps the most realistic method is to see if we can identify specific, climate events in recent history and cross reference that to the kind of detailed solar records we now have available to see if any sensible match can be identified.
As an example, if we examine known, well recorded, events over the last couple of decades, for example the ’European Heat Wave of 2003’, the ‘Winter Cold 2009/10/11’, then cross reference those events with charts of solar activity then, yes of course, the heat wave did occur during solar max and the cold winters did occur during solar minimum. However there does not appear to be any serious, specific sunspot activity that would explain the extreme nature of those events, indeed sunspot activity seemed to be ‘pretty average’ for that part of the cycle at those specific times.
Until, that is, we examine the ‘Ap’ index where we find a massive spike in recorded activity at the time of the 2003 heat wave together with deep dips in activity December 09/10/11/12.
This would imply that the impact of geo-effective activity from solar sources other than just the sunspots does make a greater contribution to climate variability than is generally accepted.
This is achieved through the interaction with the upper atmospheric profile, rather than just the pure injection of energy. It needs also to be remembered that this profile variation does have an effect on surface climate through the movement of surface air masses; this in turn can give the impression of warming when cooling is actually taking place – and vice versa – and can contribute to cooling by throwing increased amounts of warm, tropical air towards the poles from where the energy will, of course, eventually, radiate away.
Apologies for being a bit long winded !
The problem with that is they claim warming with atmospheric temperatures and not the ground temperatures. Could airplanes from the hot jet engines be the cause of this problem? More planes fly today then back in the 1970’s when satellites were first observing atmosphere temperatures. And you don’t have to be a rocket scientist to figure that one out.
Hi Anthony, When we refer to ‘Surface level’ we refer to the atmosphere at surface level, not to the ground. ‘Upper Atmosphere’ generally refers to conditions around the 500mb level and above.
Just as the surface level atmosphere is centred on 1000mb but obviously varies above and below that, so the 500mb level (or the pressure at the mean altitude of that level) varies from around 600mb over the equator to around 400mb at the poles. This latter variation is not smooth but has a ‘hump’ over the equator, the shoulder of which can vary in steepness. The ‘hump’ also moves north and south seasonally, so that ‘shoulder’ (often referred to as the ‘steering level’) moves north and south and can be steep or shallow. It is also twisted by the difference between land and sea. This is what is meant by the ‘Upper Atmospheric Profile’.
The concept that aircraft can influence the atmosphere has been put forward before, indeed the few days after 9/11, when air traffic effectively stopped, were said to be measurably different. It is more likely that any impact would be due to cloud formation from contrails rather than from heat.
Recommend https://howtheatmosphereworks.wordpress.com/historical-charts/ for an assessment of this structure over the last 120 years or so.
Also back on 9/11/2001 the planes that were grounded were only in the United States and Canada and airplanes that were headed to the United States from other countries. The rest of the world did not ground their airplanes. That means there were still airplanes flying around somewhere in the world on that day and day after. The contrails that you mentioned, is the airplane engine not burning off the fuel efficiently because of the cold upper atmosphere. And I must say, I have not seen the trails from the jet engines since the 1970’s. In the summer time we don’t see them as often it mostly happens when atmosphere is cold in the winter time, similar to the old cars with carburetor in winter you would get a white smoke trail coming out of the tailpipe of the vehicle when ground temperatures were below freezing. Because fossil fuel engines don’t burn fuel efficiently in extreme cold temperatures. Today’s vehicles on the other hand do not seem to do that because of computer controlled emissions. .