Why are some scientists skeptical of the scientists results and conclusions

Earth's surface temperature has warmed 1.5 degrees Celsius over the past 250 years and "humans are almost entirely the cause," concludes a scientific study designed to address skeptical concerns that the causes of climate change are even induced. for the man. Professor Richard Muller, a climate change physicist and founder of the Berkeley Earth Surface Temperature Project, said he was surprised by the findings. "We did not expect this result, but as scientists it is our duty to let the evidence change our minds." He added that he now considers himself a "converted skeptic" and his views have been subjected to a "total turnaround" in a short time. "Our results show that the average land surface temperature has increased by 1.5 degrees Celsius over the last 250 years, including an increase of 0.9 degrees Celsius over the last 50 years. In addition, it seems likely that essentially all of this increase results from human emissions of greenhouse gases, ”Muller wrote in an article in the New York Times. The University of California, Berkeley-based team of scientists has assembled and consolidated a set of 14.4 million surface temperature observations, collected from 44,455 sites worldwide, dating back to 1753. Previous datasets created by NASA and the National Oceanic and Atmospheric Administration (NOAA) in the US, and by the Met Office and the Department of Climate Research at the University of East Anglia in the United Kingdom only arrived until the mid-19th century and used only a fifth of the number. of weather station records

does anyone know or what?