Posted on 3 July 2017 by John Abraham

A new paper just published in the Journal of Climate is a stunning setback for the darling of cherry-picking for contrarian scientists and elected officials. Let’s walk though this so we appreciate the impact. 

The vast majority of scientists know that the climate is changing, humans are the main reason, and there are going to be severe consequences. We have decades of measurements that prove our understanding of this process. There is simply no debate or dispute. 

Despite this, there are a shrinking number of contrarian scientists, elected officials, and industry representatives that have spent endless time trying to downplay the impact. They have variously argued that the climate isn’t changing, that the changes won’t be very much, or that there are no viable solutions to the problem. Much of their position relies upon finding evidence that the current observations of warming are not great. That is, the Earth is not warming as fast as predictions. 

To support this incorrect (and intellectually dishonest) position, contrarians have scoured the data for any evidence at all that suggests the Earth is not warming. They have skipped oceans (which account for 93% of the warming). They skip the Earth’s surface temperature, ignore ice loss, ignore sea level rise, and in fact ignore everything except some select regions of the atmosphere. Their fallback position is that since a part of the atmosphere seems not to be warming very fast, this means the Earth isn’t warming or that climate models cannot be trusted. I know I know, this sounds dumb, and it is. But it is their current argument. 

But let’s pretend we are contrarians and let’s ignore the entirety of the Earth system except for this very small part. Do they have a point? There has been a lot of dispute about exactly how fast these atmospheric temperatures have been rising. Measurements are best made by weather balloons or by satellites. The satellites are convenient because they orbit the Earth quickly and can gather lots of information that is quite uniform across the globe. But satellites have their problems. 

First, they are not stable. They drift in altitude and their orbits drift horizontally. As a consequence, satellite users have to correct their data to make sure these drifts don’t give a false impression of heating or cooling. The satellites also have other issues. For instance, they have to be calibrated and they have to be stable in time. You want to ensure the temperature sensors don’t change during the satellite’s lifetime. You want to make sure that you know the location where the measurements are taken. 

In reality, the satellites make smeared measurements over a vertical column in the atmosphere. Part of that column is the lower level (called the troposphere). Another part is higher in altitude (called the stratosphere). The area of concern for this study is the troposphere (in fact the lower troposphere). But, if your smearing isn’t processed correctly, you may be measuring the stratosphere and think it is the troposphere (or vice versa). We call that potential “contamination.”

In short, you have to be really careful about satellite measurements, there is a lot of uncertainty. Despite this, contrarians have tried to tell us that satellites are better than thermometers, better than models, better than anything at measuring climate change. 

One of the groups that has promoted satellite measurements, and downplayed climate change is from the University of Alabama at Huntsville (UAH). In the past, they have falsely claimed that the atmosphere was cooling (it wasn’t, they had made a mistake). Over the years, people have found