You may be surprised to know I get Scientific American and this issue
has a very comprehensive article on GW that I cannot ignore.
it is not online at this time at sciam.com. Maybe in a few days.
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Listen the vast majority, and I mean the vast majority , of climatologists
accept that the unprecedented global warming we are seeing is due largely to
Human activity. What the flat earth crowd does is take some true fact and
then draw erroneous conclusions from it. Their goal seems to be to create the
illusion of some real controversy in the science community when none exist.
Sure there are no doubt some scientists who don't agree with the consensus, but
this happens all the time in science. If you wait for the last “skeptic” to
be convinced the state of Florida will be submerged. The skeptics are a very
small percentage. And a lot of nonsense is being used also. Some examples
1) Water is the main greenhouse gas so it's silly to worry about CO2.
It's true that water is the main green house gas , but so what. In terms
of earth temperatures and the greenhouse effect we have an energy balance
system. So the build up of CO2 (which no one can refute) is
likely causing the obviously warmer temperatures we are seeing world wide.
Think of steering your car. Does it matter or not if while you are driving
that you only turned the steering wheel just a little? Also more CO2 means more
H2O because of higher temperatures. H2O enhances the CO2 effect by about 50
percent.
2) It’s solar activity.
It’s true that the output from the Sun varies as well the orbital parameters
which effect the amount of energy we get from the sun. Again the fact that
solar variability is a factor is true. However, we have climatic records that
go back 20 million years. We can see the solar cycles and track their climate
effect. The climate models we have reproduce the observed climate cycles
very accurately until you get to the last few decades or so where the temperate
changes we are seeing diverge from the model. However, when the effects of
the increase of CO2 from 280PPM to 390 PPM are added into the models they
predict pretty much we are seeing. BTW the point of no return is expected to be
on the order of 560 PPM. Also if the bulk of heating were from solar energy
increases than we should see the warming in the upper atmosphere relative to
the lower atmosphere but instead our best data indicates just the opposite,
which is predicted for an enhanced green house effect.
3) CO2 has increased before the burning of fossil fuels
Again true. Every historical warming event is accompanied by large increases
in CO2. But this is no surprise. Any natural warming trend will increase CO2
levels because for one thing the ocean is a CO2 sink. Warmer temperatures
decrease the ability of the Oceans to hold CO2 so we see increased CO2.
However, based on historical records (ice sample, biological markers etc.) the rate
of change of CO2 we are seeing now is unprecedented over the last 20 million
years. Also we understand something about the CO2 cycle. The current cycle
looks like
Plants are taking 110 GT/yr of Carbon out of the atmosphere. (GT equals
Giga-tons)
Animal respiration is putting 55 GT/yr into the atmosphere.
Plant and animal decay are putting 51 GT/yr of Carbon into the atmosphere.
The Oceans (right now) are releasing 88 GT/yr into the atmosphere but in
parallel processes they are absorbing 90 GT/yr of Carbon . (Right now) This
gives us a Net of 2GT/yr out of the atmosphere. (Right now)
Fossil fuel burning is putting 7GT/yr of Carbon into the atmosphere and
deforestation is effectively putting about 2GT/yr of Carbon per year due to
reduced photosynthesis and plant decay.
Based on this we are increasing the Carbon content of the atmosphere by
3GT/yr.
Some of these values are more uncertain than others and this doesn't include
volcanic activity but it’s a pretty good snapshot.
I could go on but you get the picture.
Bob Zannelli