RDD_1210
Forms his own opinions
- May 13, 2010
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No, it has not been answered. Not at all. And, it is absolutely relevant to your post. A claim is not in a position to be refuted if there is no evidence for that claim in the first place.What evidence do we have that man made CO2 has significantly contributed to warming?
Old question, long since answered, irrelevant to the thread topic.
Actually, there is plenty of evidence and data to support man made global warming. If you truly want to read up on the topic and see the data for yourself you can start here
Human and Natural Drivers of Climate Change - AR4 WGI Summary for Policymakers
"Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years (see Figure SPM.1). The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land use change, while those of methane and nitrous oxide are primarily due to agriculture. {2.3, 6.4, 7.3} "
"The understanding of anthropogenic warming and cooling influences on climate has improved since the TAR, leading to very high confidence[7] that the global average net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W m–2 (see Figure SPM.2). {2.3, 6.5, 2.9} "
That site has a wealth of info that you can use to educate yourself if you actually want to form your own opinion.