Friends of Science | The Myths and Facts of Global Warming

Providing Insight Into Climate Change Myths / Facts COMMON MISCONCEPTIONS ABOUT GLOBAL WARMING

MYTH 1: Global temperatures are rising at a rapid, unprecedented rate.

FACT: The HadCRUT3 surface temperature index, produced by the Hadley Centre of the UK Met Office and the Climate Research Unit of the University of East Anglia, shows warming to 1878, cooling to 1911, warming to 1941, cooling to 1964, warming to 1998 and cooling through 2011.

The warming rate from 1964 to 1998 was the same as the previous warming from 1911 to 1941. Satellites, weather balloons and ground stations all show cooling since 2001. The mild warming of 0.6 to 0.8 C over the 20th century is well within the natural variations recorded in the last millennium. The ground station network suffers from an uneven distribution across the globe; the stations are preferentially located in growing urban and industrial areas (“heat islands”), which show substantially higher readings than adjacent rural areas (“land use effects”). Two science teams have shown that correcting the surface temperature record for the effects of urban development would reduce the reported warming trend over land from 1980 by half. There has been no catastrophic warming recorded.

MYTH 2: The “hockey stick” graph proves that the earth has experienced a steady, very gradual temperature decrease for 1000 years, then recently began a sudden increase.

FACT: Significant changes in climate have continually occurred throughout geologic time. For instance, the Medieval Warm Period, from around 1000 to1200 AD (when the Vikings farmed on Greenland) was followed by a period known as the Little Ice Age. Since the end of the 17th Century the “average global temperature” has been rising at the low steady rate mentioned above; although from 1940 – 1970 temperatures actually dropped, leading to a Global Cooling scare.The “hockey stick”, a poster boy of both the UN’s IPCC and Canada’s Environment Department, ignores historical recorded climatic swings, and has now also been proven to be flawed and statistically unreliable as well. It is a computer construct and a faulty one at that. See here for more information.

MYTH 3: Human produced carbon dioxide has increased over the last 100 years, adding to the Greenhouse effect, thus causing most of the earth’s warming of the last 100 years.

FACT: Carbon dioxide levels have indeed changed for various reasons, human and otherwise, just as they have throughout geologic time. Since the beginning of the industrial revolution, the CO2 content of the atmosphere has increased by about 120 part per million (ppm), most of which is likely due to human-caused CO2 emissions. The RATE of growth during this century has been about 0.55%/year. However, there is no proof that CO2 is the main driver of global warming. As measured in ice cores dated over many thousands of years, CO2 levels move up and down AFTER the temperature has done so, and thus are the RESULT OF, NOT THE CAUSE of warming. Geological field work in recent sediments confirms this causal relationship. There is solid evidence that, as temperatures move up and down naturally and cyclically through solar radiation, orbital and galactic influences, the warming surface layers of the earth’s oceans expel more CO2 as a result.

MYTH 4: CO2 is the most common greenhouse gas.

FACT: Greenhouse gases form about 3% of the atmosphere by volume. They consist of varying amounts, (about 97%) of water vapour and clouds, with the remainder being gases like CO2, CH4, Ozone and N2O, of which carbon dioxide is the largest amount. Hence, CO2 constitutes about 0.04% of the atmosphere. While the minor gases are more effective as “greenhouse agents” than water vapor and clouds, the latter are overwhelming the effect by their sheer volume and – in the end – are thought to be responsible for 75% of the “Greenhouse effect”. (See here) At current concentrations, a 3% change of water vapor in the atmosphere would have the same effect as a 100% change in CO2.Those attributing climate change to CO2 rarely mention these important facts.

MYTH 5: Computer models verify that CO2 increases will cause significant global warming.

FACT: The computer models assume that CO2 is the primary climate driver, and that the Sun has an insignificant effect on climate. Using the output of a model to verify its initial assumption is committing the logical fallacy of circular reasoning. Computer models can be made to roughly match the 20th century temperature rise by adjusting many input parameters and using strong positive feedbacks. They do not “prove” anything. Also, computer models predicting global warming are incapable of properly including the effects of the sun, cosmic rays and the clouds. The sun is a major cause of temperature variation on the earth surface as its received radiation changes all the time, This happens largely in cyclical fashion. The number and the lengths in time of sunspots can be correlated very closely with aver

Source: Friends of Science | The Myths and Facts of Global Warming


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