Ice ages and Earth orbit around sun

Dear Sir, — I would refer to my letter concerning climate change in last week’s Chronicle and the editor’s insistence that climate change is largely caused by human activity and his reference to the views of the Royal Society in which they largely support his opinion, notwithstanding the fact that there are many scientists who think differently.
I happened to state in my letter that “the problems of the planet likely to affect the human race could be of the planet’s own making as it enters (here I should have more accurately stated — already entered) another period of its varied life”.
It might interest people to know that an ice-age is known as a long period of reduction in the temperature of the Earth’s surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. 
Earth’s climate alternates between ice-ages and greenhouse periods and individual pulses of cold climate within an ice-age are termed “glacial periods” and intermittent warm periods within an ice-age are called “interglacials” with both climate pulses being identified as part of the Quaternary period and the present greenhouse effect is known as the Holocene Epoch which commenced approximately 11,000 years ago.
Scientists are also aware that ice ages are caused by variations in the Earth’s orbit around the Sun. When an intensification of sunlight initiates the end of an ice-age, they believe, carbon dioxide is somehow flushed out of the ocean causing a big amplification of the initial warming. It is also believed that volcanic eruptions under the sea make a large contribution to this process, and obviously there are many other contributory factors but it is entirely wrong to think that any limitations to be initiated by humans (if they ever happen) are going to have any dramatic or far-reaching benefits.
I realise it is trendy to think of and push ahead with the view that climate change is the result of the contribution made by the burning of fossil fuels, the use of cars and planes and the destruction of trees and rain-forests but in reality changes are afoot in any case as the foregoing information implies. 
We should not be afraid to tell our young people that there are problems ahead due to the possibility of an increase in sea levels and the flooding this would bring because people settled and built large cities on the coasts of most countries. 
They will at least have the opportunity to make changes whatever form these will have to take — that is if anyone takes any notice.
The most annoying aspect of discussions about climate change is that in Britain the authorities are still building super highways and wish to have a third runway at Heathrow. 
A large number of people still think that they cannot do without several plane trips abroad every year and don’t see why there should be a reduction of cars on the road especially if it affects their situation. 
Even watching a programme such as Escape To The Country people still clamour for wood-burning stoves.
There are times when one doesn’t know whether to laugh or cry about the whole situation, and if I hear another person say that they are only thinking of the future for their grandchildren I think I will have a pink fit or something similar.

RS NORBURY
Biddulph.
Factcheck.
• The editor does not “insist” that climate change is largely caused by human activity — it is the overwhelming scientific opinion, hence the “fact” part of a factcheck.
• Successive reports by the Intergovernmental Panel on Climate Change have evaluated the causes of climate change. The most recent special report on global warming of 1.5 degrees confirmed that the observed changes in global and regional climate over the last 50 or so years are almost entirely due to human influence on the climate system and not natural causes.
• There are not “many scientists who think differently”. It is generally said that 97%-99% of climate scientists accept the change is man-made. As a comparison with other fringe beliefs, a survey last year found that 5% of British people did not believe the holocaust occurred; 3% of adult Americans think the Earth is flat, 4% think lizard people control politics and 5% think Sir Paul McCartney died in 1966. (A rather striking 13% think Barack Obama is the Antichrist).
• Scientists know the change is manmade because atmospheric carbon dioxide concentrations can be measured over the last 650,000 years and they are higher today than at any time — and 35% higher than before the industrial revolution. Human activities alone can account for the increase in carbon dioxide concentrations, and computer models that include manmade warming can predict observed changes.
• Volcanic eruptions, under or over the sea, do not make “a large contribution” to climate change.
• The warming of the planet is at the surface — external factors would warm the atmosphere all the way down.
• It is true that ice ages are cyclical. Models predict the current (unusually long) warm climate should last another 50,000 years, although climate change might delay the next glacial period by an additional 50,000 years.