In 1589, Princess Anne of Denmark left to marry King James VI of Scotland. En route, her boat was struck by storms. Someone had to be blamed and, as was standard for the time, witches were the usual suspects.
More than 100 suspected witches were duly arrested and at least four people were burned at the stake. The fact James and Anne went on to be happily married, apparently unmolested by tempests, must have reassured them that justice had been done.
The supposed connection between human activity and the weather is an instinctive one and perhaps helps explain the remarkable persistence of incorrect views on climate change.
Every time there is a big cyclone a finger is soon pointed to the modern witch of carbon dioxide emissions. This continues despite there being no evidence that extreme weather events have increased because of global warming. The latest report of the Intergovernmental Panel on Climate Change admits that “evidence suggests slight decreases in the frequency of tropical cyclones making landfall in the North Atlantic and the South Pacific”.
A significant issue with climate change science is that often only one side of the debate is heard, so clear exaggerations and untruths can remain unchallenged.
The US military pioneered the use of so-called red teams whose job was to argue against prevailing wisdom, making its strategies more robust. Climate change science would benefit from more red team analysis.
For example, if you listen to the mainstream media, you would not realise that since the last major attempt to forge a climate change agreement in Copenhagen six years ago, the science has become less certain and gives us less reason to worry. This is primarily because the globe’s climate seems less sensitive to increases in carbon dioxide than previously thought.
In just the past 18 years we have experienced one-third of the increase in atmospheric carbon dioxide since the Industrial Revolution, but temperatures have not increased as expected.
Satellite data shows no or only minimal warming, and surface-based measures show a warming rate far below projected climate models. At a US Senate hearing this week, John Christy, a lead author on previous IPCC reports, presented evidence that, on average, climate models over-estimated the rate of warming by three times compared with what actually has occurred.
If these models cannot replicate the past, how can we rely on them to predict the future?
The IPCC has recognised this uncertainty by winding down its estimates of how sensitive the climate is to carbon dioxide levels.
In 2007 it reported a possible range of 2C to 4.5C, whereas last year it reported a range of between 1.5C and 4.5C. More recent evidence indicates that the figures could be even lower.
The greatest uncertainty revolves around debates about the climate impact of aerosols in the atmosphere. A paper published this year in the Journal of Climate by Bjorn Stevens from the Hamburg-based Max Planck Institute for Meteorology argues that the impact of aerosols on climate is significantly smaller than the latest IPCC report assumes.
Using these estimates shows that the upper bound of climate sensitivity should not be 4.5C but just 2.2C.
That is pretty close to what we were told the world needed to avoid dangerous climate change. Readers who are paying attention will note that some green activists are now saying we need to keep warming below 1.5C rather than 2C.
When the facts change, so can your arguments.
Whatever the facts, too much weight is placed on conformity in climate change science — most widely demonstrated by the inane argument that “97 per cent of scientists agree”.
Presumably 97 per cent of pundits agreed in the power of witchcraft in the 16th century.
Science is not a democracy. Scientific knowledge progresses from the ruthless exposure of competing hypotheses to criticism. But who is doing that critique of climate change theories today?
Public funding of climate change science almost exclusively flows to one side of the debate. Even just a small sliver of the reported $US100 billion ($139bn) fund that Paris is creating for developing countries could make a difference.
We need red team funding of scientists who take a different view on climate change. Even if such teams ultimately take positions that are incorrect, by challenging the climate zeitgeist they would make our scientific knowledge stronger. That means the policies we implement would be based less on dogma and more on a true appreciation of how carbon dioxide emissions affect our world.
This article was originally published in The Australian on 18 December 2015.
