An international panel of scientists on April 13 told us greenhouse gas emissions were accelerating despite reduction efforts. But not everyone believes in human-caused climate change. Rebecca Fox looks at why.
In some quarters, climate change has been relegated to one of those topics not to talk about at a dinner party, like religion and politics.
Man-made climate change - increased carbon dioxide emissions due to the burning of fossil fuels by humans - is not a concept accepted by all.
University of Victoria head of psychology Associate Prof Marc Wilson said his research and that of his collaborators, based on large-scale surveys of New Zealanders, suggested about 60% believed in anthropogenic or human-driven climate change.
Those who did not believe were more likely to be male and older.
''Unsurprisingly, people who are religious, and politically conservative are also less likely to endorse climate change.''
Conservatism on social issues was more strongly associated with opposition than economic conservatism, although both were associated with scepticism.
''Interestingly, income is not related to climate change belief in New Zealand, where it's the case in the US that rich equals sceptic.''
The ''gap'' between expert and lay opinion had to be about more than just evidence, or there would be more consensus on climate change, he said.
So the reason for their position was part of a broader world view.
''For example, people who are socially conservative tend to think the world is a more dangerous place than other people. I would suggest that if you are worried about your security then there's a good reason to deny the extent of climate change because it makes you anxious.
''Because our attitudes reflect drives around things like physical security it's no surprise we have deeply held views.''
However, there was a well-known tendency for all people to pay attention to things that supported what they already believed, he said.
''You see this a lot in a lot of places but in the context of climate change you'll see it play out with the different studies or evidence that people look to in order to support their belief.''
While not a layman, Dr Bob Carter, formerly of Dunedin, firmly believes climate change is not man-made.
He is a geologist who studied and taught at the University of Otago from 1964 to 1980, and is one of three lead authors of the Nongovernmental International Panel on Climate Change's latest report.
Now living in Australia, he visited Dunedin last week for ''nostalgia'' reasons rather business.
When asked if he was a climate ''denier'' Dr Carter said ''the term has been applied''.
The NIPCC had set itself up as a parallel organisation to mainstream science's InterGovernmental Panel on Climate Change, releasing reports in similar timeframes, giving its view on the same data it says the IPCC uses. The difference being the NIPCC was not influenced by government or politics, and did not ignore research, Dr Carter said.
''We think we have another way of interpreting the data from the alarmist view of the IPCC.''
When it was suggested setting up carbon taxes was the last thing governments wanted to do, Dr Cater said governments' role in the IPCC was their way of controlling people by alarming them and raising revenue.
The group of senior, mostly retired scientists, was not ''the self-selecting'' group of experts the IPCC was, he said.
When asked about the thousands of scientists who support the IPCC views, he countered with the Oregon Petition in the United States which reportedly had 30,000 signatures supporting the claim that there was no conclusive evidence human release of CO2 was causing catastrophic heating of the earth.
''In Australia there has been a very large swing in public opinion toward not accepting alarmist advice.''
Looking at it objectively there were more benefits from climate change than negatives, he said.
''The misinformation the public is being fed is not what they should be worried about.''
People should be worried about natural climate variability, which caused the major natural hazard events such as floods, cyclones and bushfires, as reducing CO2 emissions would not work, Dr Carter said.
University of Victoria School of Geography, Environment and Earth Sciences Associate Prof Dr James Renwick sits on the other side of the fence.
He has contributed to the InterGovernmental Panel on Climate Change and firmly believes in its science, which is based on completed peer-reviewed research by independent scientists.
''It's all looked at in great detail by a large number of groups around the world.
''The basic story has been verified over and over.''
Any changes made to the science had to be agreed by the scientists.
The amount of carbon dioxide in the atmosphere had been tested all over the world since the 1950s with the same answer everywhere, he said.
''We know for sure CO2 concentrations ... have gone up steadily since records began.''
A test developed by a New Zealander enabled scientists to determine the carbon dioxide in the air today comes from the burning of fossil fuels.
It had been known for 150 years that greenhouse gases were critically important in determining the temperature on the earth.
''The first climate change forecast was published in 1896 just as industralisation was beginning.''
What was happening to the climate fitted the expectations of scientists and the climate models built up over the years.
''They have been tested at great length.''
While increased carbon dioxide might help plants grow bigger and faster, it would only work if there was sufficient moisture and temperatures for them to grow.
''For a while the increased CO2 does mean growth but then it turns to custard when it gets too hot and there's not enough moisture.''
Research had been done in New Zealand which showed forestry might benefit from increased temperatures, but dairy cows would become more susceptible to heat stress.
It could mean having to shift whole continents of production across the world to where conditions would be more suitable, Dr Renwick said.
''There would have to be a period of transition but there would be some years crops would fail.''
No government wanted to impose a carbon tax. They wanted to tell their people ''nice things'', he said.
Other arguments he had heard were that scientists were in it for the money, he said.
''I wish that was true but it's not my experience.''
The Supporters
InterGovernmental Panel on Climate Change
- International body for assessing the science related to climate change.
- 803 scientists involved in latest report
- Set up in 1988 by the World Meteorological Organisation and United Nations Environment Programme
- Provides policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.
- Does not conduct its own scientific research.
The latest claims
- Global emissions of greenhouse gases have risen to unprecedented levels
- Emissions grew more quickly between 2000 and 2010 than in each of the three previous decades.
- Need to lower global greenhouse gas emissions by 40% to 70% compared to 2010 by mid-century.
- Increasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts.
- Climate change is expected to lead to increases in ill health in many regions and especially in developing countries with low income
- Major future rural impacts are expected in the near term and beyond through effects on water availability and supply, food security, and agricultural incomes, including shifts in production areas of food and non-food crops across the world
- For medium to high-emission scenarios, ocean acidification poses substantial risks to marine ecosystems, especially polar ecosystems and coral reefs
The Deniers
Non-governmental International Panel on Climate Change
- 50 scientists contributed to latest report
- International panel of non-government scientists and scholars
- ''Wholly independent of political pressures and influences''
- Concluded the IPCC was biased on projections of climate change
- NIPCC is a project of three ''independent'' nonprofit organisations: Science and Environmental Policy Project (SEPP), Centre for the Study of Carbon Dioxide and Global Change (CO2 Science), and The Heartland Institute.
- Concludes rising temperatures and atmospheric CO2 levels are causing no net harm to the global environment or to human health
The latest claims
- Atmospheric carbon dioxide is not a pollutant. It is a non-toxic, non-irritating, and natural component of the atmosphere.
- There is little or no risk of increasing food insecurity due to global warming or rising atmospheric CO2 levels.
- Rising temperatures and atmospheric CO2 levels do not pose a significant threat to aquatic life.
- A modest warming of the planet will result in a net reduction of human mortality from temperature-related events.
