LAYING TEN GLOBAL WARMING MYTHS


Professor R.M. Carter
Hon. FRSNZ

Marine Geophysical Laboratory (Node C)
Sporing Road South, James Cook University
Townsville, Qld. 4811, AUSTRALIAContact RMC

Original article (in .doc format) at:  http://members.iinet.net.au/~glrmc/new_page_1.htm

 

Myth 1     Average global temperature (AGT) has increased over the last few years.

Fact 1       AGT has remained steady, or slightly declined, since 1998.

 

Myth 2     During the late 20th Century, AGT increased at a dangerously fast rate and reached a high point of unprecedented magnitude.

Facts 2     The recent rate of AGT rise has been between 1 and 2 deg. C/century, which falls squarely within natural rates of climate change for the last 10,000
 years. AGT has been several degrees warmer than today many times in the recent geological past.

 

Myth 3     AGT was relatively unchanging in pre-industrial times, has sky-rocketed since 1900, and will increase by several degrees more over the next 100

                years (the Mann, Bradley & Hughes "hockey stick" curve).

Facts 3     The Mann et al. curve has been exposed as a statistical contrivance. There is no convincing empirical evidence that past climate was unchanging, nor that 20th century changes in AGT were unusual or unnatural.

 

Myth 4     Computer models predict AGT will increase by 6 deg. C or more over the next 100 yr.

Facts 4     Deterministic computer models do. Other equally valid (empirical) computer models predict cooling.

 

Myth 5     Warming of 1-2 deg. C will have catastrophic effects on ecosystems and mankind alike.

Facts 5     Ecosystems have been adapting to climate change since time immemorial. The result is the process that we call evolution. Mankind can adapt to all
    climate extremes.

 

Myth 6     Human addition of carbon dioxide to the atmosphere is causing dangerous warming, and is generally harmful.

Facts 6     No human-caused warming can yet be detected that is distinct from natural system variation and noise. Any additional human-caused warming which
occurs will probably amount to less than 1 deg. C. Atmospheric carbon dioxide is a beneficial fertilizer for plants, including cereal crops, and also aids efficient evapo-transpiration.

 

Myth 7     Changes in solar radiation cannot explain recent changes in AGT.

Facts 7     The sun's output varies on many time scales (including that of the 11-year sunspot cycle), with concomitant effects on Earth's climate. More than 50% of the 0.8 deg. C rise in AGT observed during the 20th century can be attributed to solar change.

 

Myth 8     Unprecedented melting of ice is taking place in both the north and south polar regions.

Facts 8     Both the Greenland and Antarctic ice sheets are growing in thickness. Sea ice around Antarctica is growing. Temperature is falling at the South Pole.
Temperature in the Arctic Ocean region is just now achieving the levels of warmth experienced during the early 1940s, and the region was warmer still (sea-ice free) during earlier times.

 

Myth 9     Human-caused global warming is causing dangerous global sea-level (SL) rise.

Facts 9     SL change differs from time to time and place to place; between 1955 and 1996, for example, SL at Tuvalu fell by 105 mm (2.5 mm/yr). Global average
SL is a statistical measure of no value for planning purposes. The global average SL rise of 1-2 mm/yr that has occurred over the last 200 years shows little sign of increasing.

 

Myth 10   An increase in AGT during the late 20th century has led to an increase in the number of severe storms (cyclones) or in storm intensity.

Facts 10   Meteorological experts are agreed that no increase in storms has occurred beyond that associated with natural variation of the climate system. The
argument that storms have increased in their intensity as a result of warming remains the subject of strong dispute.