please tell me about this. allow for the fact I need hand holding through physics.

Point A

• The Maunder Minimum is a period of time in the sun’s recent history (mid 1600’s to early 1700’s) where sunspot activity was at a minimum.

Point B

• During that same period on Earth there was a period of cooling called the Little Ice Age.

People like to link A with B but there is very little physical evidence to support it.

diddly-squat said:

Point A

• The Maunder Minimum is a period of time in the sun’s recent history (mid 1600’s to early 1700’s) where sunspot activity was at a minimum.

Point B

• During that same period on Earth there was a period of cooling called the Little Ice Age.

People like to link A with B but there is very little physical evidence to support it.

great delivery diddly. ta.

sarahs mum said:

please tell me about this. allow for the fact I need hand holding through physics.

OK. Sunspots have an effect on the total electromagnetic radiation we receive on Earth. It may surprise you that the presence of sunspots actually increases the amount of radiation we receive. Why is this? Because sunspots subtract very little from the visible light we receive but add quite significantly to the amount of UV light we receive, from memory (and don’t quote me on this) near the peak of the solar cycle, where there are the greatest number of sunspots, the UV light we receive is about 3% more.

During the “Maunder Minimum” there were very few sunspots, so the Earth was receiving less heat, so the Earth was colder on average.

At the time of the Maunder Minimum, remarkably low temperatures were recorded throughout Europe. These low temperatures caused lakes to freeze over out of season, caused crops to fail and suchlike. This was dubbed the “Little Ice Age”. The Little Ice Age coincided in time with the Maunder Minimum, but it’s still disputed whether the Maunder Minimum caused the Little Ice Age. That’s because fragmentary climate records from places other than Europe (such as Antarctica) don’t show the same drop in temperatures.

With me so far? Shall I continue?

mollwollfumble said:

sarahs mum said:

please tell me about this. allow for the fact I need hand holding through physics.

OK. Sunspots have an effect on the total electromagnetic radiation we receive on Earth. It may surprise you that the presence of sunspots actually increases the amount of radiation we receive. Why is this? Because sunspots subtract very little from the visible light we receive but add quite significantly to the amount of UV light we receive, from memory (and don’t quote me on this) near the peak of the solar cycle, where there are the greatest number of sunspots, the UV light we receive is about 3% more.

During the “Maunder Minimum” there were very few sunspots, so the Earth was receiving less heat, so the Earth was colder on average.

At the time of the Maunder Minimum, remarkably low temperatures were recorded throughout Europe. These low temperatures caused lakes to freeze over out of season, caused crops to fail and suchlike. This was dubbed the “Little Ice Age”. The Little Ice Age coincided in time with the Maunder Minimum, but it’s still disputed whether the Maunder Minimum caused the Little Ice Age. That’s because fragmentary climate records from places other than Europe (such as Antarctica) don’t show the same drop in temperatures.

With me so far? Shall I continue?

sure. that was like diddly’s precis but with a little added extra.

sarahs mum said:

please tell me about this. allow for the fact I need hand holding through physics.

To continue. That there was a drop in global temperature during the period of the Little Ice Age is undisputed. But different reconstructions give different values for the global temperature drop. Between 1000 AD and 1600 AD, the Earth’s temperature dropped somewhere between 0.2 degrees and 1 degrees Celsius, depending on the reconstruction, two independent reconstructions give a 1 degree drop and two independent reconstructions give a 0.2 degree drop. seven other reconstructions give intermediate values.

It’s not easy to determine if the Maunder Minimum caused the Little Ice Age because of something called the “amplification factor”. A percentage change in incoming solar radiation gives an exactly predictable change in Earth’s surface temperature unless Earth’s albedo changes (there’s an extra factor here due to changes in ocean thermal mixing bout I’m going to sweep that under the carpet). Earth’s albedo depends on the global cloud cover which in turn depends on the surface temperature so there’s a feedback loop. The ratio of the actual temperature change due to a change in incoming solar radiation to the prediction of that change assuming constant albedo is known as the amplification factor.

The actual value of the amplification factor remains unknown, but what is known is that it’s too small to explain modern global warming by recent increases in sunspot activity by at least a factor of four, and probably by more like a factor of ten.