Friday, October 28, 2016

Global Warming - or a new "Little Ice Age"

There is evidence that our sun goes through a cycle measured in centuries in which the amount of heat and light it gives off varies slightly, as a result there have been colder centuries which are sometimes known as "little ice ages" and it was during the last such period, in Georgian times, that London could hold "frost fairs" on the river Thames which had frozen over in winter.

The mid 20th-century was one of the periods when the sun gave off more heat and light, making that period much warmer than the previous two centuries, and I recall that during my childhood there were scientific predictions that this phase would come to an end within a century causing the climate to become significantly colder.

Latterly, of course, we have had the opposite fear, that the increase in the amount of carbon in the atmosphere would lead to global warming.

The great majority of scientists believe that man-made global warming is taking place as a result of human emission of carbon compounds into the atmosphere. It is not just an issue of warming: and even if you don't accept the case that the earth is getting warmer there is evidence that the rising amount of carbon in the atmosphere is causing considerable harm to our environment in other ways, such as making the seas more acid, which if it continues will devastate marine life, destroying fisheries and killing the algae which make a large part of the world's oxygen.

However, there is another view, not just among cranks but among some scientists.

I see that one learned professor has published a paper which rejoices in the title of

"The New Little Ice Age Has Started"

This argues that the sun has started another phase when it produces less heat and light and the amount of both we get from the sun has been dropping sine 1990. It is suggesting that the planet will enter a phase of "deep cooling" at the middle of this century - my grandchildren may live to see "Frost Fairs" again if the author is right.

It turns out that it is chapter seventeen of a collection of papers called

"Evidence-Based Climate Science (Second Edition)
Data Opposing CO2 Emissions as the Primary Source of Global Warming"


which as the sub-title suggests is written by scientists who don't regard man-made CO2 emissions as the main source of climate change. The editor is a Professor Don Easterbrook.

I am still keeping an open mind on this. The evidence for majority view among scientists sounds pretty convincing to my non-expert brain and certainly strong enough that on the precautionary principle we ought to restrict carbon emissions.

However, it is always a good idea to listen to both sides of the argument. Our earth's ecosystem is a fantastically complex thing and the one thing we can be certain about is that neither side of the global warming argument understands it as well as they would like to. Both sides may have insights which are valuable.

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