Keith Rankin, 28 February 2002
On Sunday Chris Laidlaw, on his radio show (National Radio), said that all except a few "flat earthers" accept that global warming is a reality.
Well, I am no flat earther. I do believe that the earth is getting warmer. What worries me, though, is that the real issues are not being addressed.
Is humankind the cause of global warming? Is the present phase of global warming exceptional, or is it explicable as part of the natural waxing and waning of the earth's climate? And, is any of this relevant to our moral duty to care for this planet, our home?
There is a perception that the mission of "greenies" is to "save the planet". This idea of saving-the-planet belongs in the realm of pre- Copernican thought; to the time when humanity was assumed to occupy the centre of the universe. We all know that the planet will still be here long after humankind has become extinct.
We just need a sense of history to appreciate that the planet has many times been through worse than anything human beings could possibly do to it. Indeed it makes good sense to argue that the mass extinctions of quarter of a billion years ago and 65 million years ago were events of "creative destruction"; events which increased both biodiversity and the capacity of living organisms to enjoy being alive.
What has happened to global climate over the last 100 years? It's not controversial. It has warmed. When did most of the warming take place? Between 1900 and 1945, actually. (See www.me3.org/issues/climate/westerndebateall_files/v3_slide0008 _image010.gif.) The earth actually cooled from 1945 to 1975. The warming returned over the last 25 years. We do not know if the very latest (ie post-1997) figures represent fluctuations about the latest trend, or an acceleration of that trend. (See 1998 Was Warmest Year Of Millennium, Climate Researchers Report on www.scienc edaily.com/print/1999/03/990304052546.htm.)
Our explanation for climate change over the century must give reasons for why the world got hotter in the beginning of the century, but did not get hotter in the middle of the century. Maybe it had something to do with the sun's natural variability of output? If so, can we rule out the sun as the main cause of post-1975 global warming?
If there has been a dramatic turning point, it happened in the later part of the 19th century. Yes, it could have been in some way linked to the industrial revolution in Europe. But why then did the much greater level of industrialisation in the 1950s and 1960s not cause further global warming?
Lets consider the last millennium. The controversial new presentation is popularly known by Americans as the "hockey stick" graph. (See, for example, http://www.vision.n et.au/~daly/hockey/hockey2.gif, noting that the yellow zone represents the large margin of statistical error.) The graph conflates modern data with historical estimates of global temperature based on the measurements of tree rings. To get the graph to really look like an ice hockey stick, it is necessary to project the 20th century pattern to the year 2050 or beyond (as in www.me3.org/issues/climate/westerndebateall_files/v3_slide0016 _image021.gif).
What is most worrying to me about the hockey stick graph is its failure to show the well-documented "Little Ice Age" (see www.vehiclechoice.or g/climate/cutler.html) which peaked in the 1690s. (The massive size of the Fox and Franz Joseph Glaciers in the 18th century was one feature of the Little Ice Age.) This graph (http://www.vision.net.au/~daly/hockey/MWE-LIA.gif), first published in 1995 by the Intergovernmental Panel on Climate Change (IPCC), gives a very good impression of the generally accepted view of climate change over the last 1,000 years. There is as yet not enough evidence in total to show that 20th century global warming is not simply a recovery from the Little Ice Age.
In the process of discounting the Little Ice Age, we also lose sight of just how warm the first three centuries of the millennium were. We really do not know if it is warmer today than it was in AD1100, when the Vikings roamed the northern seas.
These past climatic events are very important. Arguably, the transition from feudalism to capitalism - usually dated to the 15th century - would not have happened had there been no Little Ice Age. African political economist and historian Ali Mazrui spoke of the "frozen ecology of capitalism" in his Africans television documentary series.
The hockey stick graph does not constitute a paradigm shift in our interpretation of climate history. It's just one of many inexact sets of estimates of climate in our past. Unfortunately, it has been widely accepted as gospel truth by many scientists and journalists with an agenda to promote the belief that the late 20th century represents a strong discontinuity in global climate change.
Agenda-motivated science is bad science. In this case, it, like all bad science, has the potential to backfire. A credible refutation of the belief that humans are causing global warming could discredit fear-based attempts to promote a reduction in global CO2 emissions into the atmosphere.
We should limit our emissions of carbon for the simple reason that we should respect our home, and the rights of future generations who will inherit our home. Good behaviour follows from good morality, not from bad science or from the rewriting of history to make it look as if climatic patterns were stable in the past.
It is very unlikely that humans will ever have more than a marginal influence on world climate. However, a marginal influence may be significant, much as a butterfly's flutter could conceivably initiate a wave of worldwide "chaos". The human influence on climate could be the proverbial "straw that breaks the camel's back" leading to human (though not planetary) extinction.
The corollary of our moral rule - to respect always our planetary home - is that if our home is under threat (eg from causes beyond human control) then we must do nothing to aggravate that threat.
The more difficult moral problem is what whether we should try to act to reverse any processes of natural climate change. A nuclear winter might just do the trick. Indeed the biggest volcanic explosion of the millennium - Tambora in Indonesia in 1815 - caused something like a global winter that year.
My example of course suggests a negative answer. We serve ourselves and our planetary home best if we tread lightly; if we take our shoes off at the front door, so to speak. By basing our actions on universal moral principles, our historians and scientists become free to make good history and good science. There should be no pressure to oblige the scientific community to reach politically correct conclusions.
Climate change is a reality. It has always been a reality. The scientific debate is meaningless if scientists are under pressure to attribute natural climate change to artificial causes.
If the sea level rises 1 metre in the next 100 years (as it is forecast to do), that will make a difference to our lives. But not as big a difference as that faced circa BC9700 when the sea rose 50 metres in about 40 years. The world continued then. Humankind survived. We need (indeed we have) better reasons than a possible threat to our shorelines to make us behave well towards our planetary home.