"IS INCREASING CO2 A DANGER OR A BENEFIT?"

Excerpt from this link:

An email from Prof. Bob Carter [bob.carter@jcu.edu.au], Marine Geophysical Laboratory, James Cook University, Townsville, Australia

David Whitehouse has contributed another insightful essay [See immediately below], and I am confident that most of your readers will agree with the thoughts that he expresses. However, I must take exception to one sentence, which is:

"Clearly the Earth’s natural state is not to have so much CO2 in its atmosphere and it would be prudent to reduce it".

The Earth has no "natural" level of CO2 for Earth's atmosphere. It is estimated that past CO2 levels have varied up to 20 times the present level, and there is no evidence that higher levels (and especially moderately higher levels such as doubling) have been ecologically "damaging".

Quite the contrary, in fact. As you and David will be well aware, atmospheric CO2 is a stimulant to plant growth and to more efficient plant use of water. Additionally, extra CO2 probably has a mild (NOT dangerous) warming effect, which on the precautionary principle is a definite benefit at this stage of the natural climate cycle.

In summary, (i) there is no such a thing as a "natural" level of CO2 in the atmosphere, and (ii) while no one can predict exactly all the consequences of increasing atmospheric CO2, the odds strongly favour it being beneficial. From which it follows that claims that reducing human CO2 emissions would be "prudent" are false.

Finally, anyone with doubts as to the benefit of mild warming might like to consult the views of the people in the southern hemisphere who have just experienced an extremely harsh winter, or those persons in the northern hemisphere who appear to be about to receive the same.