In light of this post, I wish to draw attention to some helpful tools.
I already linked to phpSyntaxTree, which allows you to easily draw diagrams using a syntax like this:
[S [NP This graphic][VP [V summarizes][NP [N data][that-clause [Subord that] [VP [V refutes] [NP a related myth[that-clause [Subord that] [NP publications now supporting the scientific consensus [that-clause [Subord that] [NP the world][VP is warming due to increased carbon dioxide]]] [VP were predicting in the 1970s [that-clause that the world would cool.]]]]]]]]]

You might be able to jump start your trees using the <a href="http://nlp.stanford.edu:8080/parser/">Stanford parser[/url] or the <a href="http://tomato.banatao.berkeley.edu:8080/parser/parser.html">Berkeley parser[/url]. However, you'll have to perform a quick conversion of parentheses to square brackets first.
I haven't looked at it in much detail, but the Stanford parser's parse of the sentence above appears to be essentially correct:
[ROOT
[S
[NP [DT This] [NN graphic]]
[VP [VBZ summarizes]
[NP
[NP [NNS data]]
[SBAR
[WHNP [WDT that]]
[S
[VP [VBZ refutes]
[NP [DT a] [JJ related] [NN myth]]
[SBAR [IN that]
[S
[NP
[NP [NNS publications]]
[VP
[ADVP [RB now]]
[VBG supporting]
[NP
[NP [DT the] [JJ scientific] [NN consensus]]
[SBAR [IN that]
[S
[NP [DT the] [NN world]]
[VP [VBZ is]
[VP [VBG warming]
[ADJP [JJ due]
[PP [TO to]
[NP [VBN increased] [NN carbon] [NN dioxide]]]]]]]]]]]
[VP [VBD were]
[VP [VBG predicting]
[PP [IN in]
[NP [DT the] [NNS 1970s]]]
[SBAR [IN that]
[S
[NP [DT the] [NN world]]
[VP [MD would]
[VP [VB cool]]]]]]]]]]]]]]
[. .]]]
.