Guest post by Alec Rawls

Nice hype by Matt Drudge, whose three linked quotes are all from the BBC’s one brief paragraph of text, but the accompanying video (full transcription below) is more substantial, with scientists talking about the likelihood of an extended Maunder Minimum type period low solar activity and the cold temperatures that coincided with the Maunder Minimum during the 1600’s.

Professor Richard Harrison from the Rutherford Appleton Laboratory is clear about the correlation [at 1:57]:

The Maunder Minimum of course was a period of almost no sunspots at all for decades and we saw a really dramatic period where there were very cold winters in the northern hemisphere. It was a period where you had a kind of mini ice-age. You had a period where the Thames froze in winters and so on. It was an interesting time.

BBC science correspondent Rebecca Morelle doesn’t shy away from the possible implications today:

So does a decline in solar activity mean plunging temperatures for decades to come?

Best of all is Dr. Lucie Green from University College in London, who describes the unsettled state of the science [at 3:35]:

It is a very very complex area because the sun’s activity controls how much visible light the sun gives out, but also how much ultraviolet light and x-rays that the sun emits and they create a web of changes up in the earth’s atmosphere producing effects that actually we don’t fully understand.

Green then wraps up the segment by declining to suggest that anthropogenic warming can be expected to outweigh solar cooling:

… on the one hand we’ve got perhaps a cooling sun, but on the other hand you’ve got human activity that can counter that and I think it is quite difficult to say actually how these two are going to compete and what the consequences then are for the global climate.

The weak link is solar physicist Mike Lockwood who makes irrational and unsupported claims about solar activity only affecting regional climate and not having a global effect.

The BBC voice-over sets up Lockwood’s unsupported speculation:

BBC: Less solar activity means a drop in ultraviolet radiation. Mike Lockwood says this seems to affect the behavior of the jet stream. The Jet stream changes its pattern. This ends up blocking warm air from reaching Northern Europe. This causes long cold winters, but what about global temperatures as a whole? Lockwood [at 5:03]: One has to make a very clear distinction between regional climate and global climate. If we get a cold winter in Europe because of these blocking events it’s warmer, for example, in Greenland, so the average is almost no change, so it is a redistribution of temperature around the North Atlantic.

As Stephen Wilde has been pointing out for years, the wider meanders in the polar jet that seem to be associated with low solar activity can be expected to cause a net increase in cloudiness which would increase the earth’s albedo, having a global cooling effect. The jet stream follows the boundry where cold polar air slides beneath and pushes up warmer temperate air, creating storm tracks. Not only do wider meanders create longer storm tracks but the resulting cloud cover occurs at lower latitudes, where the incidence of incoming solar radiation is steeper, making the albedo reflection stronger.

Snow cover albedo effects would likely also be global, not just regional. A warmer Greenland has almost zero marginal albedo effect: it’s 98% white anyway. But a snow covered Europe and North America will reflect away a lot of sunlight. Also, the important thing over large parts of Asia and North America will not be temperature—it’s always going to be cold enough to snow during the Siberian winter—but the extent of the storm tracks, so that cloud and snow albedos both increase with the amplitude of the jet stream meanders, as seems to have been the pattern with the current solar lull. Here is a graphic showing the 21st century’s high average snow anomalies (from Rutgers, via Brett Anderson at Accuweather):

Lockwood is up against the paleologic evidence as well. He is suggesting that, while the Little Ice Age may have been induced by low solar activity, it was a northern-hemisphere-only event, but recent studies indicate that it was a global climate swing, as was the Medieval Warm Period.

Overall though, a very good report from the BBC. Have the recent revelations about top level BBC collusion with green propagandists reduced the power of the warming alarmists to censor other views? In any case, it is good to see them do some real reporting.

Full transcript (not provided by the BBC – is this unusual? – so I transcribed it myself)

BBC voice-over: The wonder of the northern lights reminds us of the intimate connection we have with our star. The aurora borealis happens when the solar wind hits the earth’s upper atmosphere, but many of these displays may soon vanish. Something is happening to the solar activity on the surface of the sun: it’s declining, fast.

Professor Richard Harrison, Rutherford Appleton Laboratory [0:28]: Whatever measure you use, it’s coming down, the solar peaks are coming down, for example with the flares. It looks very very significant.

Dr. Lucie Green, University College London [0:36]: The solar cycles now are getting smaller and smaller. The activity is getting less and less.

BBC: There is a vast range of solar activity: sunspots, intensely magnetic areas seen here as dark regions on the sun’s surface; solar winds and uv light radiate toward the earth; flares erupt violently and coronal mass ejections throw billions of tons of charged particles into space. Solar activity rises and falls in 11-year cycles and right now we are at the peak, the solar maximum, but this cycle’s maximum is eerily quiet.

Harrison [1:18]: I’ve been a solar physicist for 30 years. I’ve never seen anything quite like this. If you want to go back to see when the sun was this inactive, in terms of the minimum we’ve just had and the peak we have now you’ve got to go back about a hundred years, so this is not something I’ve seen in my lifetime, it’s not something that a couple of generations before me have seen.

BBC: The number of sunspots is a fraction of what scientists expected, solar flares are half. Richard Harrison is the head of space physics at the Rutheford-Appleton Laboratory in Oxfordshire. He says the rate at which solar activity is falling mirrors a period in the 17th century where sunspots virtually disappeared.

Harrison [1:57]: The Maunder Minimum of course was a period of almost no sunspots at all for decades and we saw a really dramatic period where there were very cold winters in the northern hemisphere [not only the northern hemisphere – A.R.] . It was a period where you had a kind of mini ice-age. You had a period where the Thames froze in winters and so on. It was an interesting time.

BBC: Rivers and canals froze across Northern Europe. Paintings from the 17th century show frost-fairs taking place on the Thames. During the “great frost” of 1684 the river froze over for two months, the ice was almost a foot thick. The Maunder Minimum was named after the astronomer who observed the steep decline in solar activity that coincided with this mini ice-age.

BBC science correspondent Rebecca Morelle [2:46]: The Maunder Minimum came at a time when snow cover was longer and more frequent. It wasn’t just the Thames that froze over. The Baltic Sea did too. Crop failures and famines were widespread across Northern Europe. So does a decline in solar activity mean plunging temperatures for decades to come?

Dr. Lucie Green [3:04]: We’ve been making observations of sun spots which are the most obvious sign of solar activity from 1609 onwards and we’ve got 400 years of observations. The sun does seem to be in a very similar phase as it was in the run-up to the Maunder Minimum, so by that I mean the activity is dropping off cycle by cycle.

BBC voice-over: Lucie Green is based at the Mullard Space Science Laboratory in the North Downs. She thinks that lower levels of solar activity could affect the climate, but she’s not sure to what extent.

Green [3:35]: It is a very very complex area because the sun’s activity controls how much visible light the sun gives out, but also how much ultraviolet light and x-rays that the sun emits and they create a web of changes up in the earth-atmosphere producing effects that actually we don’t fully understand.

BBC voiceover: Some researchers have gone way further back in time, looked into the ice sheets of particles that were once in the upper atmosphere, particles that show variations in solar activity. Mike Lockwood’s work suggests that this is the fastest rate of solar decline for 10,000 years.

Professor Mike Lockwood, University of Reading [4:20]: If we look at the ice core record we can say, “okay so when we’ve been in this kind of situation before, what’s the sun gone on to do,” and based on that, and the rate of the current decline, we can estimate that within about 40 years from now there’s about a ten or twenty, probably nearer a 20% probabilility that we will actually be back in Maunder Minimum conditions by that time.

BBC: Less solar activity means a drop in ultraviolet radiation. Mike Lockwood says this seems to affect the behavior of the jet stream. The Jet stream changes its pattern. This ends up blocking warm air from reaching Northern Europe. This causes long cold winters, but what about global temperatures as a whole?

Lockwood [5:03]: One has to make a very clear distinction between regional climate and global climate. If we get a cold winter in Europe because of these blocking events it’s warmer, for example, in Greenland, so the average is almost no change [a completely unsupported conjecture that is at odds with reason and evidence A.R.], so it is a redistribution of temperature around the North Atlantic.

Morelle: The relationship between solar activity and weather on earth is complicated but if solar activity continues to fall could the temperature on earth as a whole get cooler? Could there be implications for global warming?

Dr. Lucie Green [5:38]: The world we live in today is very different to the world that was inhabited during the Maunder Minimum. So we have human activity, we have the industrial revolution, all kinds of gases being pumped into the atmosphere, so on the one hand we’ve got perhaps a cooling sun, but on the other hand you’ve got human activity that can counter that and I think it is quite difficult to say actually how these two are going to compete and what the consequences then are for the global climate.

BBC: So even if the planet as a whole continues to warm, if we enter a new Maunder Minimum the future for Northern Europe could be cold and frozen winters for decades to come, and we won’t even have bountiful displays of the northern lights to cheer us up.

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