"A Guide to Understanding Global Temperature Data" Includes: Whether we use thermometers, weather balloons, or Earth-orbiting satellites, the measurements must be adjusted for known sources of error. This is diffcult if not impossible to do accurately. As a result, different scientists come up with different global warming trends—or no warming trend at all.
So, it should come as no surprise that the science of global warming is not quite as certain as the media and politicians make it out to be.