claim: it later emerged that its creator Dr Michael Mann had spliced too [sic] datasets together – tree-rings showing temperatures going back hundreds of years, then recent thermometer readings for the more recent decades.
evidence: In these modern designs, pollution from coal-fired power plants comes from the emission of gases such as carbon dioxide, nitrogen oxides, and sulfur dioxide into the air, as well a significant volume of wastewater which may contain lead, mercury, cadmium and chromium, as well as arsenic, selenium and nitrogen compounds (nitrates and nitrites).