On the first question, it seems that none of us have enough personal scientific knowledge to be able to come to our own independent scientific conclusions or to debate with each other on a scientific level. This means that all any of us can do is quote reports that support one side of the debate or another. That seems fruitless to me.
I will freely admit that I don't have the science but that, on a common sense basis, it seems illogical to me to put pollutants into the atmosphere that needn't be there. I also believe that, since we are charged with stewardship of God's creation, it also seems logical to me that it is good to keep atmospheric pollutants down to a minimum.
On the second question, is it the case that that those who believe in human-caused climate change are righteous and that those who do not believe in human-caused climate change are sinners? As Paul would say 'By no means!' If this is 'sinful' activity, then we are ALL sinning in this way - every one of us. And if it's genuinely not sinful activity, then none of us are sinning in this way so there is no reason to be outraged. This is not an attempt at polarizing people into sinners and non-sinners according to their beliefs about a single issue.
The report Hope in God's Future published by the Joint Public Issues Team of The Methodist Church, the Baptist Union and the URC, never even gives the impression that those who believe in climate change are 'righteous'. The report consistently speaks of 'our' sin and 'our' need for repentance - clearly including the authors of the report in the indictment of sin.
The section of the report calling for repentance begins with the poem:
Thus knowing holiness and grace,Consistently, the report speaks of 'we sinners' 'our sin' 'our need for repentance'.
in humble honesty confess
we all our sins before your face,
and turn our lives to righteousness.
Those who sincerely disagree on the issue of human-created climate-change should not be scape-goatted by those who do believe. But I honestly can't see any evidence that this report is engaging in that kind of scape-goatting. If someone does see scape-goatting, maybe they can point it out?