Attribution of Northern Hemisphere Land Surface Warming (1850-2018)

The Center for Environmental Research and Earth Sciences (CERES) research group published a paper as described in their blog post that shows current estimates of global warming are contaminated by urban warming biases. The study also suggests that the solar activity estimates considered in the most recent reports by the UN’s Intergovernmental Panel on Climate Change (IPCC) likely underestimated the role of the Sun in global warming since the 19th century. The blog post states “In their latest report, the IPCC estimated that urban warming accounted for less than 10% of global warming. However, this new study suggests that urban warming might account for up to 40% of the warming since 1850. The authors compared an estimate of solar activity often used by the scientific community to the rural temperature data and they found that most of the warming and cooling trends can be explained by changing solar activity. Willie Soon and his 36 colleagues found that when using only rural data, the temperature changes shows a more cyclical behavior and less overall warming than datasets that included urban data. The abstract says “The rural and urban blend indicates a long-term warming of 0.89 °C/century since 1850, while the rural-only indicates 0.55 °C/century.”