The next lecture meeting will take place on Thursday January 14th 2010 when the subject will be: THE PSYCHOLOGY OF CREATIVE PROBLEM SOLVING to be given by Professor Fairfid M Caudle from the College of Staten Island, The City University New York.
There can be no doubt that one of the biggest challenges to Creative Problem Solving at the present time is to be found within the continuing debate concerning Climate Change and enhanced Global Warming. There has been much written on this subject and quite a lot of it can only be described as 'Bad Science'. What we at Hampstead know for certain is, that our century-long meteorological records show a rise of 2 degrees Celsius in average temperatures recorded at the Observatory during this period. But whether this is due to natural cyclic phenomena or to the industrial activities of mankind, is still open to debate. In the following article, Peter Wallis reminds us of the numerous factors that can influence climate change on our Restless Planet.
Peter R Wallis
It would be wrong to think that our planet has persisted much as it is today. There are many natural causes which have produced changes. When it first condensed, some 4.5 billion years ago, from the solar nebula it was under intense bombardment. Indeed, early in its life, it collided with another planet, destroying its original form and losing much mass to space. This mass eventually condensed into our satellite, the Moon. Evidence of such turbulent times is clearly recorded in the moon's maria, as the Moon has insufficient mass to hold an atmosphere to protect it from impacts or erode the evidence.
Other influences have been more gradual and others of a cyclical nature. A Scotsman James Croll in 1912 first described the variations in the earth's orbit and the precession of the earth's axis of rotation. His work was followed up by Milutin Malenkovitch in 1920 and is usually associated with the latter's name. The significance of these cycles for the variation of solar energy input to the Earth was proved in 1976 by scientific studies of oxygen isotopes over half a million years in cores drilled from deep ocean sediments: they show a 100,000 year cycle due to orbit eccentricity, a 43,000 year cycle from the variation in axial tilt (between 21.5 and 24.5 degrees) and a 20,000 year cycle due to axis precession.
But there have been much greater and more mysterious changes to Earth's climate – the ice ages; the geological and fossil record demonstrates their occurrence. We now recognise that the Earth has generally been much warmer than it is today but has occasional periods lasting several million years during which there are alternating 'glacial' and 'interglacial' periods with a roughly 100,000 year cycle. At present we are in the Pleistocene Ice Age, which started some 3 million years ago in the northern hemisphere. The ice started to retreat 20,000 years ago and we are now in an interglacial stage. We now recognise that the glacial/interglacial sequence is caused by the astronomical cycles mentioned above.
We know of at least four earlier ice ages:
| Permocarboniferous | 300 million years ago |
| Late Proterozoic | 600 – 800 million years ago |
| Early Proterozoic | 2.2 – 2.4 billion years ago |
| Archean | 2.9 billion years ago. |
What on Earth – or off it – caused them?
It is probable that the major cause is the movement of tectonic plates on which the continents stand, first discovered by Wegener. At one time all the continents were together, Pangea, though they are now widely distributed. Wegener showed that at the time of the Permo-Carboniferous ice age all the southern continents were together, Gondwanaland, near the south pole. These varying dispositions of continents are important to the amount of solar radiation absorbed by the earth, as land has a greater reflectivity than sea. Snow and ice have an even greater reflectivity than either land or sea. So once ice forms there is an escalating move into an ice age. Indeed there is accumulating evidence that in the late Proterozoic ice age all the land and much, perhaps all, of the sea was completely frozen; it has been called 'Snowball Earth'.
So our next puzzle is: what brings an ice age to an end? The answer is green-house gases. Most people now know about them from the current political problem of global warming caused by our burning fossil fuels, coal, gas and oil, for modern industry, transport and heating. I'll put that on one side for the moment however. It is the emission of carbon dioxide from volcanoes which stops an ice age after a few million years. Without volcanoes we would be a frozen planet. We may take note that volcanoes are closely related to the tectonic plates of the Earth. They appear at ocean spreading ridges and at subduction zones, particularly around the Pacific Ocean.
Volcanoes may have saved us from a frozen world but they can also be disasters for our environment. There are some 'small' ones we know about as they are recent: Mt St Helens in Washington State 1980, Mt Pinatubo in the Philippines 1991. There are older ones for which we have records: Mt Vesuvius near Pompeii in 79AD, Tambora 1815, Krakatoa 1883. Geological evidence shows that there were also 'super volcanoes' in the past. The US Geological Survey defines these as discharging more than 1,000 cubic kilometres of ash, lava and pumice in a single event. There is believed to have been such a one, Toba, in Indonesia some 74,000 years ago.
The remains of supervolcanoes are not so easy to recognise as the smaller ones that leave mountains; supervolcanoes destroy mountain ranges. There was one in the Rocky Mountains of Wyoming which left such an enormous caldera instead of mountains that it failed to be recognised until 1870. It is Yellowstone National Park. It erupted some 640,000 years ago. In fact there is a 350 mile string of volcanic fields generated over the last 20 million years by a hot magma chamber over which the American Plate is moving. [1]
Apart from the localised effect of volcanic eruptions, lava and pyroclastic flow, there are many noxious gases discharged into the atmosphere. Sulphur dioxide leads to aerosols which can block the sun's radiation for years and further stress life. Some thought is turning to the possibility that eruptions could be responsible for some of the mass extinctions of extant life. Over the last 550 million years five great extinctions have been deduced from the fossil record as well as lesser events. We have some clues to what happened 65 million years ago as there is evidence of an asteroid or comet impact at that time on the Yucatan Peninsula. We can only speculate about earlier ones. Recently suggestions have been made that the Toba supervolcano 74,000 years ago may have been responsible for a disastrous reduction in the human population. We know from the study of mitochondrial DNA across the world that all humans now living are descended from a very small group at such a time.
So what conclusions can we draw? Our planet is a restless one, rearranging its continents, suffering repeated ice ages and green-house warming, massive volcanic eruptions and asteroid impacts. And we must expect from time to time the extinction of many species. Against this background the current political excitement of anthropic global warming seems a very small event. It may perhaps speed up the end of the Pleistocene Ice Age, but they have come and gone many times before. And the effect will be over when all the fossil fuels have been used.
Nevertheless our modern knowledge of the planet's history and our dominant position among its living species suggests we should do something to ameliorate the changes we are making. I am not sanguine that we will cease to exploit the coal, oil and gas, however many nuclear power stations and tidal barrages we build. The growth of the human population and its wants is inexorable.
We need to devote more thought and money to engineering the planet to slow down the rate of warming and the consequent rise in sea level. Schemes to deploy a sunshade in space have been dismissed as impossibly expensive. Moreover it might be very difficult to remove it if we discovered consequences which had not been foreseen. One relatively inexpensive solution has been put forward recently, to build a fleet of wind-powered automatic ships to sail the oceans, sucking up sea water and spraying it to encourage cloud formation and reflect sunlight back to space. [2] It has been calculated that a reduction by 1 or 2 % would be enough to cancel the green-house effect of our carbon dioxide emissions. It may well be that such a plan would be cheaper than the current politically correct one of reducing carbon dioxide emissions and it would be easy to modify the scheme if necessary. The Royal Society is expected to report on the idea shortly.
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[1] Achenbach J,"When Yellowstone Explodes", National Geographic, August 2009. Back
[2]"Cloud ships on course to save the World", The Times, August 7th 2010 Back
Editor's Footnote. In their recent book: 'Global Warming & other Bollocks' [*], Professors Stanley Feldman and Vincent Marks, describe an online survey carried out in the USA, in which over 33,000 senior scientists have cast doubts about the supposed link between anthropogenic CO2 and enhanced Global Warming. They believe that there is no evidence that the warming over the last century is 'outside the parameters of natural temperature variability'. Their conclusion is that:"It is unlikely that there is any significant warming caused by anthropogenic CO2 and the 'officially' released scare stories are without scientific justification." It would seem that a large proportion of the international scientific community that does not incline to the views expressed by Government agencies is effectively being silenced. Few organizations can obtain funding for research that does not uphold the officially promoted view. Apparently, certain respected broadcasting companies believe the Global Warming case proven and refuse to give air time to opposing views. In the 21st century, this is a desperate state of affairs akin to the 17th century Catholic Church's refusal to consider the scientific evidence proving that the Earth does in fact, orbit the Sun. This attitude, coupled with the recent directive to teach Creationism in science classes and the abandoning of teaching physics in some schools, are indicators of what should be a worrying trend; a trend that could very well lead to scientific censorship and the burning of books! Enhanced Global Warming caused by the industrial activities of mankind is at best a theory. We must remind ourselves that it is the duty of science to attempt to disprove theories by rigorous investigation, measurement, observation and experiment, in order to get at the truth. Whichever way you look at it, the role of anthropogenic CO2 in enhanced Global Warming is thus far unproven and deserves more rigorous scientific investigation than it has so far received. Attempting to gag scientists who express opposing views on a half-baked theory is no way to behave in a modern technological society. Science has advanced considerably over the last four centuries, but unfortunately it would seem, politics has not. A further example of the Government's refusal to listen to scientific evidence that does not support their official stance was seen in late October when Professor David Nutt , the Government's advisor on drugs was summarily dismissed. His report concluded that certain substances are less harmful than supposed and should be re-classified at a lower rating. This evidence apparently did not coincide with Government policy and they took exception to the fact that his results entered the public domain. One should ask the question: why was his expert opinion sought in the first place if they intended to ignore it or worse to suppress it? I feel it my place to remind politicians that it is the duty of science to reveal thetruth; and sadly that is a word that many politicians seem not to comprehend. Doug Daniels. [*] Feldman & Marks' book is published by Metro Publishing. ISBN 978-1-84454-718-0 Back
Astronomers are currently celebrating the 400th anniversary of the invention of the telescope and it is a sobering thought that in 2010, the Hampstead Scientific Society will celebrate the centenary of the foundation of its Observatory. So we have been in existence for a quarter of the entire history of optical astronomy. The meteorological station was also founded at the same time and can now boast a record of 100 years of continuous daily observations from the same site. Apart from a short period during the second World War, the Observatory has provided regular public open nights throughout the winter months and is the only observatory in London that can claim this level of public service. We feel that this centenary is an event that should be celebrated. Accordingly, the Astronomy and Meteorology sections will hold a special Open Day at the Observatory on Sunday April 25th 2010. Members of the Society and invited guests are welcome to join us from 12:30 pm for a glass of wine and a light buffet and to view the small exhibition detailing the history of the Observatory & Met. Station.
In the meantime, just to remind you about the early years of the Society and the founding of the Observatory & Met. Station, I append a short history. A more detailed description can be found in: HAMPSTEAD SCIENCE 1899-1999. This excellent book edited by Philip Eden, is still available at £5.50 inc. postage from the President.
The roots of the Hampstead Scientific Society go back to Christmas 1898 when P.E.Vizard learned that a Hampstead resident, Colonel Henry Heberden J.P. had a 10.5-inch reflecting telescope that he would be happy to donate to a Society that was prepared to make it available to members of the public. Thus it was that in July 1899 at a public meeting, the Hampstead Astronomical and General Scientific Society was formed. There were many trials and tribulations in the beginning but in 1910 the Observatory, as we know it today, was established, built on top of the newly constructed underground reservoir, the property of the then Metropolitan Water Board, on a site that was the highest point in London. It was also in 1910 that Patrick Hepburn came on to the scene. Hepburn was a keen amateur astronomer and was described in the Society's history by the late Ben Boltz, as 'a man of demonic energy'. Hepburn and Vizard were the first joint Astronomical Secretaries. 1910 was the year of the return of Halley's Comet but it was rather overshadowed by the Great Daylight Comet of the same year. Halley's Comet was observed from the Observatory in 1910 and again on its return in 1986 when on that occasion, over 800 members of the public came to see it.
In the early years, the Observatory enjoyed dark skies and many valuable observations were made. Hepburn became the Director of the Saturn section of the British Astronomical Association (BAA) and the Society's 1911 report contains drawings and a map of the surface features of Mars made by members. Over the years many planetary drawings made by members have been submitted to the various observing sections of the BAA and the Society has an archive of drawings of Mars covering many oppositions from 1911 to the present day. Over the years, many amateur astronomers and even a few professionals had their first introduction to observational astronomy at the Hampstead Observatory.
In the early part of the 20th century it was still possible to make valuable observations but the Society never neglected its prime duty to allow the public access to the telescope, a duty that it has met for a century. During the winter months, from mid September to mid April, the Observatory is open on clear Friday and Saturday evenings from 8.00pm-10.00pm and on Sunday mornings from 11am-1.00pm. Visitors can just 'turn up' and view interesting objects through the fine 6-inch Cooke refractor that was presented to the Society by George Avenell in 1928. Members of the section are on hand to show visitors such sights as Saturn's rings, Jupiter's cloud belts, the craters and mountains on the Moon and some of the brighter 'deep sky' objects - star clusters, nebulae and galaxies. On Sunday mornings we can safely project an image of the Sun to reveal sunspots and faculae, when they are present.
For more information about the Observatory, the Astronomy Section and special events, please browse the Section website: www.hampsteadscience.ac.uk/astro
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Last updated 28-Jan-2018 contact