Independent Confirmation of Global Land Warming without the Use of Station Temperatures

Confidence in estimates of anthropogenic climate change is limited by known issues with air temperature observations from land stations. We test those observations using a completely different approach to investigate global land warming over the 20th century. We have ignored all land temperature observations and instead inferred the temperature from global observations of barometric pressure, sea surface temperature, and sea-ice concentration using a physically-based data assimilation system called the 20th Century Reanalysis. This independent dataset reproduces both annual variations and centennial trends in the observation-based land surface temperature datasets, demonstrating the robustness of previous conclusions regarding global warming.