Oreskes , Conway : 255 scientists wrote letter to reiterate global warming findings . Authors : Letter came after attack on scientist whose work shows human impact on climate . They say attacks similar to those aimed at science on DDT , second-hand smoke , acid rain . The immediate trigger for the letter Virginia State Attorney General Kenneth T. Cuccinelli 's recent demand that climate scientist Michael Mann , director of the Earth System Science Center at Penn State University , produce a large volume of paperwork related to his scientific research and communications with fellow scientists during his years at University of Virginia from 1999 to 2005 . Comment:
Oreskes , Conway : 255 scientists wrote letter to reiterate global warming findings . Authors : Letter came after attack on scientist whose work shows human impact on climate . They say attacks similar to those aimed at science on DDT , second-hand smoke , acid rain . Comment: