Geoscience Reference
In-Depth Information
myths, misinterpretations, and
misunderstandings of the Deniers
been the hottest on record. The warmest
years on record, since accurate measure-
ments began in the late 1800s, were 1934,
1998, and 2005.
myth : In the 1970s scientists were worried
that the Earth was cooling, and now they've
reversed their thinking. Global warming is
just the new fashion. A review of the scien-
tific literature by Thomas Peterson and as-
sociates in 2008 showed not only that there
was no rush by scientists in the 1970s to
claim that the Earth was cooling, but in
fact at that time human-caused warming
dominated the peer-reviewed literature.
The concern about a cooling Earth seems to
have come from the media: “a major cooling
widely considered to be inevitable” ( New
York Times , 21 May 1975); meteorologists
are “almost unanimous” in belief in global
cooling ( Newsweek , 28 April 1975); “Telltale
signs [of global cooling] are everywhere”
( Time , 24 June 1974).
myth : It was hotter in the “Medieval Warm
Period” than at present, so the current warm-
ing trend is just another blip in atmospheric
temperatures. It is true that between ad
800 and 1300 Europe and Eastern North
America warmed up, but this warming,
like the cooling of the Little Ice Age (1550
to 1850), may have been a regional climate
change without global implications. An
overwhelming number of climate scientists
believe that the current warming is not just
another blip. We are causing this one, and
we are here to suffer the consequences. In
the past there were probably many thou-
sands of equivalents to the Medieval Warm
Period and the Little Ice Age. Apparently
neither the Medieval Warm Period nor
the Little Ice Age affected sea level in any
substantial way. If the cooling or warming
had been global, the sea level should have
dropped or risen in response to changes in
ice accumulation in Greenland and the Ant-
arctic, just as is happening today. In fact,
the evidence (from ice cores) indicates that
current temperatures may already be higher
than those in the Medieval Warm Period.
myth : Since 1998 the Earth's atmosphere
has begun to cool. So global warming is over.
The origin of this claim is that the global
average temperature in 1998 was the high-
est recorded to date. Starting from this
high point in a curve with large ups and
downs, some deniers have determined that
the Earth is cooling. Determining trends
by starting with high points (or low points)
of a “noisy” curve is poor science. Noisy
trends must be evaluated over a long pe-
riod, not year by year. In November 2009
the Natural Environment Research Council
and the Royal Society in London issued a
statement that the previous ten years had
myth : Variations in solar activity are re-
sponsible for global warming. Stop worry-
ing about greenhouse gas emissions and stop
picking on coal and oil companies. Var ia-
tions in the Earth's orbit around the sun,
Search WWH ::




Custom Search