So, we have seen that the
planet is currently warming, but that it has been gradually warming for thousands of years,
in cycles, with cooler intervals in between. Then, around 8 to 10,000 years
ago the cycle stabilised, approximately
around the current temperature levels. The big question is, why did it happen - or put another way, why does our temperature fluctuate in the
way that it does?
Let's first investigate
whether the culprit could indeed be CO2 - man made or
otherwise. Well, as you can see from the chart below, CO2
levels have definitely varied through history, and from the temperature
chart you can also see that temperature has varied more or less in a
Dioxide Chart Sources:
2001-1958: South Pole Air Flask Data
1958-1220 B.P.: Law Dome, Antarctica
1220 B.P.- 2302 B.P.: Taylor Dome, Antarctica
2302 B.P.- 414k B.P.: Vostok Ice Core Data
2000-1979: Satellite stratospheric data
1979-1871: S. Hemisphere ground temp. data
1871- 422k B.P.: Vostok Ice Core Data
During the last 400,000
years the CO2
levels have gone up and down, between about 180 and 300ppm
(parts per million), and the only deviation in that cycle does seem to
be that in CY2000 the level stood at 370ppm. How significant is
Well, the first thing you can see
from the chart is that CO2
in our atmosphere has been increasing steadily for the last 18,000 years,
long before humans invented motor cars or chimneys. So, unless you
count campfires and intestinal gas, man played no role in the
pre-industrial increases. There's another very significant fact
from these two charts, and that is that, although temperature does go up and down
in tune with CO2
levels, temperature rise always precedes CO2
rise. In other words it's quite probable that the increasing temperature
and not the other way around - or at the very least the two parameters
are both being affected by the same driver, just on a slightly different
timescale. On the scale of this chart it is
difficult to see the effect, but it is definitely there, and so CO2
level changes cannot be causing the temperature
Worryingly, Earth's temperature and
levels today have reached levels similar to those in a previous
interglacial cycle of 120,000 - 140,000 years ago. From beginning
to end this cycle lasted about 20,000 years and this is known as the Eemian
Interglacial Period. The earth returned to a
full-fledged ice age immediately afterward!
But it is clear that
human activities do seem to have caused a "spike" in CO2
levels in the last 50 years and we are currently standing at what we are
told is a "disastrously
high" level, with catastrophic results likely for the planet. Really? No, really not.
Even if CO2 was affecting temperature, total
human contributions to greenhouse gases account for only about 0.28%
of the "greenhouse effect" (see chart below).
Anthropogenic (man-made) carbon dioxide (CO2)
comprises about 0.117% of this total, and man-made sources of other
gases (methane, nitrous oxide (NOX), other miscellaneous gases) contributes
another 0.163%. A fact which the warmists don't want you to hear
is that there is another "gas" which is equally effective as a
greenhouse gas, and it is present in vastly greater
quantities. That gas is water vapour!
of the "greenhouse effect" is due to natural causes mostly
water vapour and traces of other gases, which we can do nothing at all
about. The simple fact is that eliminating human activity
altogether would have little impact on climate change. There are a
number of other factors which we are increasingly becoming aware have an influence on global
climate. They include solar cycles (short and long term), volcanic
currents, clouds, the eccentricity of the Earth's orbit around the sun,
and the galactic environment in which the sun and planets find
themselves as the sun orbits the centre of the Milky Way galaxy.
Yes, lots of things - and we are going to examine them in more detail in
the following pages.
"Human additions" represent such a small percentage of
the total Greenhouse Effect (0.28%) that they are barely visible
in this "pie chart" at the scale represented.
Comparing greenhouse gases by strict concentration only,
the total human component is somewhere between 0.1% and 0.2%,
depending on whose numbers you use. Adjusted for GWP, the total
human contribution to Earth's overall greenhouse effect
is about 0.28%.
Chart compiled using data provided
by the US Department of Energy.