Professor Nigel Weiss, Emeritus Professor in Mathematical Astrophysics at Cambridge, has affirmed the announcement by scientists that global warming is primarily a man-made problem.

Weiss echoes the findings of the Intergovernmental Panel on Climate Change (IPCC), published in Paris on 1 February. The panel stressed that humans are the most likely cause of global warming, emphasising that a concerted and universal effort to reduce emissions is necessary to lessen the risks.

There has been recent support for suggestions that solar activity is a more significant cause than human consumption, and that a fall in solar activity would lead to a cooling that would negate the effect of greenhouse gases. Weiss has rejected this stance.

“Although solar activity has an effect on the climate, these changes are small compared to those associated with global warming,” he said. “Any global cooling associated with a fall in solar activity would not significantly affect the global warming caused by greenhouse gases.”

Solar activity occurs in stars such as our own sun, where sunspots are the site of strong magnetic fields. The number of spots appearing varies cyclically with a period of approximately 11 years, with a boom currently taking place which scientists predict will be followed by a slump. Satellite measurements have shown that solar irradiance decreases by 0.1 per cent from sunspot maximum to sunspot minimum, causing a reduction of about 0.1 degrees Celsius in average global temperature.

Weiss insists that this rate of change is small compared to that which will manifest itself should fossil fuels continue to be burnt at the present rate. The IPCC has also reiterated the need for a global reduction. The USA has addressed a memorandum, endorsed by President Bush, to the panel. It advocates “modifying solar radiance” as a more viable solution than a decrease in consumption.

A number of nuclear weapons scientists at the Lawrence Livermore Laboratory in California have put forward the proposal of launching a million tonnes of tiny aluminium balls filled with hydrogen into the atmosphere each year, to act as a barrier against global warming. Sea water and sulphate particles have also been suggested as possible materials, but critics have argued that all of these methods are expensive, dangerous and do nothing to reduce the concentration of carbon dioxide in the atmosphere.

universal effort to reduce emissions is necessary

Weiss affirms that the current situation is of grave concern. Scientists also acknowledge that increased levels of carbon dioxide threaten to acidify oceans, causing severe consequences for the food chain. This counters those who deny the existence of global warming.

This view has been promoted by Channel 4 director Martin Durkin. In The Great Global Warming Swindle, an upcoming documentary to be broadcast on Channel 4, man-made climate change is called “a lie ... the biggest scam of modern times”. He continued, “The truth is that global warming is a multibillion-dollar worldwide industry: created by fanatically anti-industrial environmentalists; supported by scientists peddling scare stories to chase funding; and propped up by complicit politicians and the media ... The fact is that CO2 has no proven link to global temperatures ... solar activity is far more likely to be the culprit.”

Educated at Clare College, Weiss discovered the process of ‘flux expulsion’ by which a conducting fluid undergoing rotation acts to expel the magnetic flux from the region of motion, and which is now readily accepted as a frequent occurrence in the sun and other stars. He was President of the Royal Astronomical Society between 2000 and 2002.
Emma Inkester