evidence: It is important to note, first off, that no data have been "altered" or destroyed in this process – all the raw data remain available for investigation by anyone who has the inclination (as I’ll show below). But this process can lead to large adjustments to the raw data, and in at least some instances the adjusted data can suggest long-term warming even when the raw data indicate cooling. This appears to have happened at the Paraguay stations mentioned in the article – the raw temperature recordings suggest cooling over decades, whereas warming appears after the raw data have been adjusted by NASA and NOAA.