Those looking for the culprit
responsible for global warming have missed the obvious choice
- the sun. While it may come as a newsflash to some, scientific
evidence conclusively shows that the sun plays a far more important
role in causing global warming and global cooling than any other
factor, natural or man-made. In fact, what may very well be the
ultimate ironic twist in the global warming controversy is that
the same solar forces that caused 150 years of warming are on
the verge of producing a prolonged period of cooling.
The evidence for future cooling
is supported by considerable scientific research that has only
recently begun to come to light. It wasn't until 1980, with the
aid of NASA satellites, that scientists definitively proved that
the sun's brightness - or radiance - varies in intensity, and
that these variations occur in predictable cyclical patterns.
This was a crucial discovery because the climate models used
by greenhouse theory proponents always assumed that the sun's
radiance was constant. With that assumption in hand, they could
ignore solar influences and focus on other influences, including
That turned out to be a reckless
assumption. Further investigation revealed that there is a strong
correlation between the variations in solar irradiance and fluctuations
in the Earth's temperature. When the sun gets dimmer, the Earth
gets cooler; when the sun gets brighter, the Earth gets hotter.
So important is the sun in climate change that half of the 1.5°
F temperature increase since 1850 is directly attributable to
changes in the sun. According to NASA scientists David Lind and
Judith Lean, only one-quarter of a degree can be ascribed to
other causes, such as greenhouse gases, through which human activities
can theoretically exert some influence.
The correlation between major
changes in the Earth's temperature and changes in solar radiance
is quite compelling. A perfect example is the Little Ice Age
that lasted from 1650 to 1850. Temperatures in this era fell
to as much as 2° F below today's temperature, causing the
glaciers to advance, the canals in Venice to freeze and major
crop failures. Interestingly, this dramatic cooling happened
in a period when the sun's radiance had fallen to exceptionally
low levels. Between 1645 and 1715, the sun was in a stage that
scientists refer to as the Maunder Minimum. In this minimum,
the sun has few sunspots and low magnetism which automatically
indicates a lower radiance level. When the sun began to emerge
from the minimum, radiance increased and by 1850 the temperature
had warmed up enough for the Little Ice Age to end.
The Maunder Minimum is not
an isolated event: it is a cyclical phenomenon that typically
appears for 70 years following 200-300 years of warming. With
only a few exceptions, whenever there is a solar minimum, the
Earth gets colder. For example, Europe in the 13th and 15th Centuries
experienced significantly lower temperatures and in both cases
the cold spells coincided with a minimum. Similar correlations
were found in the 9th Century and again in the 7th Century. Since
8700 B.C., there have been at least ten major cold periods similar
to the Little Ice Age. Nine of those ten cold spells coincided
with Maunder Minima.
There is no reason to believe
that this 10,000-year-old cycle of solar-induced warming and
cooling will change. Dr. Sallie Baliunas, an astrophysicist with
the Harvard-Smithsonian Center for Astrophysics and one of the
nation's leading experts on global climate change, believes that
we may be nearing the end of a solar warming cycle. Since the
last minimum ended in 1715, Baliunas says there is a strong possibility
that the Earth will start cooling off in the early part of the
Indeed, it could already be
happening. Of the 1.5° F in warming the planet experienced
over the last 150 years, two-thirds of that increase, or one
degree, occurred between 1850 and 1940. In the last 50 years,
the planetary temperature increased at a significantly slower
rate of 0.5° F - precisely when dramatically increasing amounts
of man-made carbon dioxide emissions should have been accelerating
warming. Further buttressing the arguments for future cooling
is the evidence from NASA satellites that the global temperature
has actually fallen 0.04° F since 1979.
Of course, it is impossible
to precisely predict when solar radiance will drop and global
temperatures will begin falling. But one thing is certain: There
is little evidence that mankind is responsible for global warming.
There is considerable evidence that the sun causes warming and
will most likely stimulate cooling in the not so distant future.
# # #
John K. Carlisle is the Director
of The National Center for Public Policy Research's Environmental
Policy Task Force. Comments may be sent to JCarlisle@nationalcenter.org.