News Story

The Earth is getting hotter. That was the stark message given to Penistone Conservatives by Prof. Valentina Zharkova. Prof. Zharkova was speaking at their annual dinner held at the Dog & Partridge on Friday 23^rd November when she gave a brief presentation highlighting factors which have influenced the Earth’s climate over the past 400,000 years.

Visible light, ultra violet, heat radiation and the solar wind are primary factors affecting global temperature and historical data shows these to vary with the length of the sunspot cycle – in 1880 this was 11.8 years but by 1980 it had reduced to 10.3 and over the same period the average global temperature increased by 0.6 degC¹.

Oscillations in global mean temperatures are correlated with corresponding oscillations in solar activity so it may be expected that the 90-year Gleissberg cycle of sunspot activity, which modulates the intensity of the 11-year cycle, possesses a considerable potential to accumulate an effective surplus of irradiance, or to induce a steadily decreasing level of radiant flux density. This 0.6 degC is an expected temperature increase caused by the known changes of the solar activity that is overridden by much higher temperature increase recorded in the past decade. This extra-increase was quickly attributed to increase of green house gases produced by anthropogenic activity on the Earth.

What about greenhouse gases and the main component – carbon dioxide? They help our planet become warmer and warmer since the heat does not leave the Earth. But is the current situation unique in the Earth’s evolution? Analysis of ice in Antarctica proves that levels of carbon dioxide in the atmosphere over the past 400,000 years have shown significant fluctuation rising rapidly as each ice-age has ended. This analysis was based on the effect of the close correlation between levels of carbon dioxide and those of deuterium² in the ice on the fact that the latter being an indicator of the temperature at the time.

But the similar analysis of the melting of Iceland ice in the modern era (1550 to 1990) compared with the solar activity data is available and it is shown to lag behind the increases in solar activity by around ten years, or one solar cycle, suggesting that other as yet unknown factors may be involved. Hence, carbon dioxide levels have risen and fallen long before there was any industrial activity. And we still are not fully aware why it happened. For example, the effect of fluctuations in the Sun’s radiation and high energy particle flows results in much lower levels of cosmic rays reaching the Earth and must also be taken into account as it leads to more clouds which contribute significantly to the greenhouse effect.

Professor Zharkova pictured with Cllrs. Marsh, Barnard and Hand-Davis

400,000 Years of Climate Change

Do other planets tell us anything? An increase in storms on Jupiter indicates increased temperatures whilst photographs of Mars show some melting of the frozen carbon dioxide at its southern pole between 1999 and 2001 – “Perhaps the Martians ought to sign the Kyoto Treaty!” Joked Prof. Zharkova.

But that does not mean Man is not harming the planet and no action needs to be taken to restrict producing more waste. Industrial and domestic pollution and, in particular, freons from aerosols damage the ozone layer in the upper atmosphere and expose life on Earth to the harmful effects of UV radiation. There are many others being investigated and their effect on the atmosphere composition and temperature are not yet fully understood.

Should we be sceptical when we hear claims about climate change? “We should be sceptical about everything…” Observed Prof. Zharkova. “…always look at the evidence and make up your own minds.”

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1. Friis-Christensen, E., and K. Lassen, Length of the solar cycle: An indicator of solar activity closely associated with climate, Science, 254, 698-700, 1991

2. Deuterium or heavy hydrogen is an isotope of hydrogen which differs from normal hydrogen by having a neutron in its nucleus. The hydrogen atom consists of one positively charged proton and one negatively charged electron, deuterium has one uncharged neutron in addition.

3. Visit Prof. Zharkova’s web page at the University of Bradford:-

http://www.inf.brad.ac.uk/staff/index.php?type=p&u=vvzharko

4. To view the slides used in the presentation - Click here...