It is disturbing that many recent statements on climate change by influential people are not supported by hard evidence.

For instance, Professor Ralph Chapman's statement that the globe risks a tipping point if emissions are not reduced by 2015 is unsupported by hard evidence, as is David Parker's claim that if we do nothing to reduce emissions, New Zealand could be up to $500 million worse off by 2012.

This is not true because, if we adopt the Emissions Trading Scheme, electricity bills alone will increase by more than $500 million each year.

On Kyoto, lawyer Alistair Hercus recently claimed that "as a country we have to pay". In fact, the Kyoto protocol says nothing about enforcement and as yet there are no international emissions enforcers to act as judge, jury and executioner.

We can opt out of Kyoto whenever we like or, like most other countries, pretend to support the protocol and, at the same time, do little or nothing.

These statements and government policies on greenhouse gases, carbon trading and promoting renewable energy are based on the beliefs that the world is warming due to man-made greenhouse gases; that promoting renewable energy will make a substantial difference to New Zealand's greenhouse gas emissions; and that if New Zealand reduces its greenhouse gas emissions it would affect the world climate. All these beliefs are not true.

The evidence is unequivocal. Measurable, let alone dangerous, manmade global warming is not happening, and is not likely to happen in the future. The major cause for concern is the possibility of severe cooling.

Global climate has always changed and recent climate changes are not unusual. The world was warmer in the mediaeval warm period, in the Roman warm period and on many occasions before then. During these periods agriculture and civilisations flourished. During cold periods like the little ice age there was famine, plague and war.

Both surface temperature records and the much more accurate records from satellite observations show there was a brief warming period from 1975-98. Since then, the world has cooled and is now at the same temperature it was in 1995. Nobody knows when, or if, world temperatures might increase.

Since the research for the 2007 Intergovernmental Panel on Climate Change report was completed in mid 2006, researchers have discovered that warming since 1975 is not caused by greenhouse gases. Greenhouse gas warming would be at a maximum 10,000m above the tropics.

Observations from balloons and satellites have shown that warming is not happening. Therefore greenhouse gases such as carbon dioxide are not a major factor in the world climate. This fact alone is sufficient to sink the manmade global warming hypothesis.

Computer-based climate models provide the only "evidence" supporting claims that the world is warming, that it will be dangerous, that there will be rapid rises in sea levels and the like, yet these same models failed to predict the temperature peak in 1998 and the steady cooling trend that set in from 2002.

It is obvious that the models have failed to predict major climatic events such as El Nino (1998) and La Nina (2007-08).

The models are not an accurate representation of the world climate system and their input data is inaccurate, therefore their outputs are worthless. This fact alone is sufficient to sink the manmade global warming hypothesis.

It is often claimed that because a "consensus" of scientists agree that manmade global warming is happening, it must be true. This is nonsense for two reasons. The first is that many distinguished scientists strongly disagree. So, by definition, there is no consensus.

But even if a consensus did exist, it would make no difference to the real world. For instance, it would not be hard to find a consensus of reverends who firmly believe the world was created a few thousand years ago. But the existence of this consensus would not stop evolution in its tracks. Science is about evidence and facts, not beliefs.

Carbon dioxide is, most definitely, not a pollutant. It is as essential to life on earth as is oxygen or water. Pollutants are, by definition, something that we would be better off without. Without carbon dioxide most of the life on earth would die within a few weeks.

But there is one fact that we can be sure of: the moderate increase in carbon dioxide in the last 100 years or so has benefited mankind because it has boosted plant growth and food production by at least 15 per cent.

More evidence is gathering that the sun, not greenhouse gases, drives our climate. Records going back thousands of years show a close correlation between sunspots and climate.

The theory is that sunspot- related effects influence the number of high-energy cosmic rays reaching the atmosphere and that these cosmic rays affect cloud formation.

Very soon, a major experiment will be set up to test this theory. If it is shown to be correct, that alone will be sufficient to sink the hypothesis of manmade global warming.

There have been very few sunspots over the past few years and the next sunspot cycle, 24, is beginning but weak.

History tells us that such circumstances are associated with quite severe cooling, possibly similar to the little ice age.

If this happens, the present financial upheavals will be exacerbated by reduced agricultural output, stormy weather and, possibly, famine.

There is more authoritative scientific information in the report Nature, Not Human Activity, Rules the Climate at the website