According to an ongoing temperature analysis conducted by scientists at NASA’s Goddard Institute for Space Studies (GISS), the average global temperature on Earth has increased by a little more than 1° Celsius (2° Fahrenheit) since 1880. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.15-0.20°C per decade.

https://earthobservatory.nasa.gov/world-of-change/global-temperatures

The glacial cycle averages about 100,000 years, consisting of about 90,000 years of the glacial period, when mile-thick continental glaciers blanketed much of the Northern and Southern Hemispheres including Canada, Russia, Northern Europe and Northern USA, and about 10,000 years of interglacial, the warm period of the present.

Earth is now 11,500 years into the current warm interglacial, and our planet may re-enter the glacial period at any time.

https://wattsupwiththat.com/2019/09/01/the-next-great-extinction-event-will-not-...

Is the Sun driven by two dynamos, each running on slightly different 11 year cycles?

Many people are talking about a new forecast of a mini-ice age (which seems to be an increasingly popular thing to predict.)

This one comes from a paper published last year but presented at the Royal Astronomical Society last week.

Shepard, Zharkov and Zharkova may have gotten us a step closer to understanding why the solar cycle varies in length from 8 to 14 years. Since the level of solar activity correlates with both the the length of the current solar cycle and the surface temperatures on Earth one solar cycle later (the notch-delay theory, and see the work of David Archibald),  it may make it possible to predict the climate decades in advance.

(With the caveat that this new study is still a model, correlation is not causation, etc.)

One of the better descriptions comes from Astronomy Now.

The Sun, like all stars, is a large nuclear fusion reactor that generates powerful magnetic fields, similar to a dynamo. The model developed by Zharkova’s team suggests there are two dynamos at work in the Sun; one close to the surface and one deep within the convection zone.

They found this dual dynamo system could explain aspects of the solar cycle with much greater accuracy than before — possibly leading to enhanced predictions of future solar behaviour. “We found magnetic wave components appearing in pairs; originating in two different layers in the Sun’s interior.

They both have a frequency of approximately 11 years, although this frequency is slightly different [for both] and they are offset in time,” says Zharkova.

The two magnetic waves either reinforce one another to produce high activity or cancel out to create lull periods.

With the Sun, we struggle for good data. Shepard et al only have three sunspot cycles of magnetic field data to go on but used the longer sunspot records as well.

The rest here,

https://joannenova.com.au/2015/07/is-a-mini-ice-age-coming-in-2030-and-does-the-...