Henrik Svensmark, Professor, DTU, Copenhagen
Published 9/9/2009 at. 03:00
In fact global warming has stopped and a cooling is begun. No climate model has predicted a cooling of the Earth, on the contrary. This means that projections of future climate are unreliable, “writes Henrik Svensmark.
The star that keeps us alive, have over the last few years have been almost free of sunspots, which are the usual signs of the Sun’s magnetic activity.
In last week reported the scientific team behind Sohosatellitten (Solar and Heliospheric Observatory) ‘the number of sunspot-free days suggest that solar activity is heading towards its lowest level in about 100 years. Everything indicates that Sun is going into a hibernation-like state, and the obvious question is whether it has any meaning for us on Earth.
If you ask the International Panel on Climate Change IPCC, which represents the current consensus on climate change, the answer is a reassuring “nothing”. But history and recent research suggests that it probably completely wrong. Let us take a closer look at why.
Solar activity has always varied. Around the year 1000, we had a period of very high solar activity, which coincided with the Medieval Warm Period. It was a period when frosts in May was almost unknown and of great importance for a good harvest. Vikings settled in Greenland and explored the coast of North America.Altogether it was a good time. For example, China’s population doubled over this period. But after about 1300 decreased solar activity, Earth began to get colder and it was the beginning of the period we now call the Little Ice Age. In this cold period, all the Viking settlements in Greenland. Sweden surprised Denmark to walk across the ice, and the London Thames froze repeatedly. But more serious was the long periods of crop failures which resulted in a poorly nourished population, because of disease and hunger was reduced by about 30 per cent. in Europe.
It is important to note that the Little Ice Age was a global event. It ended in the late 19th century and was followed by a rising solar activity. Over the past 50 years, solar activity was the highest since the Medieval Warm Period of 1,000 years ago.And now it seems that Sun has changed again and is heading towards what solar scientists call a “grand minimum” as we saw in the Little Ice Age.
The coincidence between solar activity and climate through the ages is explained away as coincidence. But it turns out that almost no matter when you look and not only the last 1,000 years, there is a line. Solar activity has repeatedly over the past 10,000 years has fluctuated between high and low. In fact the Sun over the past 10,000 years spent in a sleep mode approx. 17 per cent. of the time with a cooling of the Earth to follow.
One can wonder why the IPCC does not believe that Sun’s changing activity affects the climate, but the reason is that only changes in solar radiation.