A new analysis (Scafetta, 2021) suggests:
• Urban Heat Island (UHI) effects can raise city temperatures 6-9°C above the temperatures in surrounding rural areas. These significant biases are not sufficiently removed from instrumental records.
• Sea surface temperatures and land temperatures showed matching variations and amplitudes from 1900 to 1980. After 1980, the land surface temperatures rose substantially more, suggesting nearly half of the land temperature increase is non-climatic.
• Tree ring temperature reconstructions showed a strikingly similar pattern of amplitude and oscillation prior to the 1980s. After the 1980s, the instrumental record claims more than twice as much warming as the proxy records.
• Between 25-45% of the warming from 1940-’60 to 2000-’20 appears to be artificial, or non-climatic.
• Climate models overestimate the 1940-’60 to 2000-’20 climatic warming by about 40% in hindcasts.