We are often told we must cut carbon dioxide emissions drastically and without delay. The first urgent call came over 15 years ago at the Earth Summit in Rio de Janeiro.

But despite innumerable international meetings since then, each one producing promises and agreements, emissions from almost every country in the world have continued to rise.

Given the potentially serious risks posed by human-caused global warming, it is a curious fact that almost everyone promises to make drastic cuts in emissions that no one will live up to. There are signs that this is set to continue.

A growing number of people believe that stopping global warming has become their lowest priority, according to a Pew Research Centre survey in the United States earlier this year. The same conclusion can be drawn from a recent opinion poll by the AA in New Zealand of 1300 of its members.

One reason for this trend could be the difficulty many have in reconciling apparently conflicting evidence put before them. For instance, according to the United Nation's World Meteorological Organisation, the official climate record shows there has been no global warming for the past decade, despite steadily rising carbon dioxide concentrations in the atmosphere.

Some climate scientists claim this is a sign of a changed temperature trend, others argue it is snapshot in a highly variable climate system. Those in the former group point to new evidence that an extended period of cooling has begun.

The Sun was more active during much of the 20th century than it was for the previous 1000 years. Now, however, the trend appears to have reversed.

Solar activity is exceptionally low and there is no sign that this may change in the near future.

According to Dean Pesnell of Nasa's Goddard Space Flight Center: "Researchers are now seeing the dimmest Sun in their records.

"The change is small, just a fraction of a per cent, but significant. Questions about effects on climate are natural if the Sun continues to dim."

Predictions of future climate are usually based on global climate models. Up until now, these models have failed to consider variable energy from the Sun. The significance of this cannot be overstated as the Sun is the only source of energy to power Earth's climate, so all global climate change is directly or indirectly linked to it.

There is little doubt that average annual global temperature has been generally trending upwards in line with the expectations of many climate scientists. The cause, however, is debatable since the trend started before modern industrialisation began pumping millions of tonnes of carbon dioxide into Earth's atmosphere.