Ice cores record climate trends back beyond human measurements
Posted on 07/06/2004 3:40:43 PM PDT by Happy2BMe
A new analysis shows that the Sun is more active now than it has been at anytime in the previous 1,000 years.
Scientists based at the Institute for Astronomy in Zurich used ice cores from Greenland to construct a picture of our star's activity in the past.
They say that over the last century the number of sunspots rose at the same time that the Earth's climate became steadily warmer.
This trend is being amplified by gases from fossil fuel burning, they argue.
'Little Ice Age'
Sunspots have been monitored on the Sun since 1610, shortly after the invention of the telescope. They provide the longest-running direct measurement of our star's activity.
The variation in sunspot numbers has revealed the Sun's 11-year cycle of activity as well as other, longer-term changes.
In particular, it has been noted that between about 1645 and 1715, few sunspots were seen on the Sun's surface.
This period is called the Maunder Minimum after the English astronomer who studied it.
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Ice cores record climate trends back beyond human measurements
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Over the past few thousand years there is evidence of earlier Maunder-like coolings in the Earth's climate - indicated by tree-ring measurements that show slow growth due to prolonged cold.
In an attempt to determine what happened to sunspots during these other cold periods, Dr Sami Solanki and colleagues have looked at concentrations of a form, or isotope, of beryllium in ice cores from Greenland.
The isotope is created by cosmic rays - high-energy particles from the depths of the galaxy.
The flux of cosmic rays reaching the Earth's surface is modulated by the strength of the solar wind, the charged particles that stream away from the Sun's surface.
And since the strength of the solar wind varies over the sunspot cycle, the amount of beryllium in the ice at a time in the past can therefore be used to infer the state of the Sun and, roughly, the number of sunspots.
Latest warming
Dr Solanki is presenting a paper on the reconstruction of past solar activity - entitled Cool Stars, Stellar Systems And The Sun - at a conference in Hamburg, Germany.
He says that the reconstruction shows the Maunder Minimum and the other minima that are known in the past thousand years.
But the most striking feature, he says, is that looking at the past 1,150 years the Sun has never been as active as it has been during the past 60 years.
Over the past few hundred years, there has been a steady increase in the numbers of sunspots, a trend that has accelerated in the past century, just at the time when the Earth has been getting warmer.
The data suggests that changing solar activity is influencing in some way the global climate causing the world to get warmer.
Over the past 20 years, however, the number of sunspots has remained roughly constant, yet the average temperature of the Earth has continued to increase.
This is put down to a human-produced greenhouse effect caused by the combustion of fossil fuels.
This latest analysis shows that the Sun has had a considerable influence on the global climate in the past, causing the Earth to warm or chill, and that mankind is amplifying the Sun's latest attempt to warm the Earth.
Dang it, beat me to it.
President Bush also spends his free time turning out 5 legged frogs and Vice President Cheney tattoes Haliburton on their backs (it is true! Michael Moore said so).
No kidding. Here in Wisconsin we topped out at 64, before dropping down back 61 by around 4:00 this afternoon. The rainiest spring I can remember, followed by the coolest June, with July on track for more of the same.
Is that Midway Island?
Cool, time to crank out the old shortwave radio.
bump!
keiki beach its right out my back door i love it here
>So even though they have only been monitoring for 396 >years, they know with absolute certainty that the sun is >now the most active its been in the last 1000 years. Junk >science.
Ok, so did you even bother to read the article? (Obviously not)
Go back and read the article and pay close attention to the part about them testing ice cores with the known data and going back through the past 1000 years or so.
HOT HOT HOT!!?? Time to form the Freeper Conga line!
"Sunspots reaching 1,000-year high..."
I just want to know who was counting 1000 years ago?
Wasn't that suppose to be sometime this month?
This could be really 'series' y'know! Me'be even, really, really, series!
Back then, a sunny day was as rare as an eclipse.
Quit leaving your windows open.
How do you lighten a fork over there? Here we just bite off a tine or two...
Whatever, we must deal with what we find.
George W. Bush will be reelected by a margin of at least ten per cent
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How Climate Made History 1300-1850
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El Nino and the Fate of Civilizations
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How Climate Changed Civilization
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