evidence: These adjustments have long been a heated point of debate. Many climate sceptics like to argue that scientists "exaggerate" warming by lowering past temperatures and raising present ones. Christopher Booker, a climate sceptic writing in the Sunday Telegraph in 2015, called them "the greatest scientific scandal in history". A new report from the rightwing US thinktank, the Cato Institute, even claims that adjustments account for "nearly all the warming" in the historical record. [...] The figure below shows the net effect of all the adjustments to land stations to the global land temperature record. Adjustments increase the overall land temperature warming by 16% between 1880 and 2016. Most of this is concentrated in the earlier part of the temperature record. Since 1970, adjustments only increase warming by 3%.