Posted on 18 April 2023 by John Mason, BaerbelW

On February 14, 2023 we announced our Rebuttal Update Project. This included an ask for feedback about the added "At a glance" section in the updated basic rebuttal versions. This weekly blog post series highlights this new section of one of the updated basic rebuttal versions and serves as a "bump" for our ask. This week features "Are surface temperature records reliable?". More will follow in the upcoming weeks. Please follow the Further Reading link at the bottom to read the full rebuttal and to join the discussion in the comment thread there.

At a glance

It's important to understand one thing above all: the vast majority of climate change denialism / skepticism / call-it-what-you-likeism does not occur in the world of science, but on the internet. Specifically in the blog-world: anyone can blog or have a social media account and say whatever they want to say. And they do. We all saw plenty of that during the Covid-19 pandemic, seemingly offering an open invitation to step up and proclaim, I KNOW BETTER THAN ALL THOSE SCIENTISTS!

So anyway, at one time in the recent past, certain dubious individuals from the blogosphere had a go at discrediting temperature records. They thought that if temperature records could be discredited, then it followed that global warming could be declared a hoax. Never mind all the other indicators pointing firmly at warming, such as huge reductions in sea ice, poleward migrations of all sorts of species, retreating glaciers and rising seas.

But they forgot one thing. Professional climate scientists already knew a great deal about things that can cause positive outliers in temperature datasets. One example will suffice. When compiling temperature records, NASA's Goddard Institute for Space Studies goes to great pains to remove any possible influence from things like the urban heat island effect. That effect describes the fact that densely built-up parts of cities are likely to be a bit warmer due to all of that human activity.

How they do this is to take the urban temperature trends and compare them to the rural trends of the surrounding countryside. They then adjust the urban trend so it matches the rural trend – thereby removing that urban effect. This is not 'tampering' with data: it's a tried and tested method of removing local outliers from regional trends to get more realistic results.

As this methodology was being developed, some findings were surprising at first glance. Often, excess urban warming was small in magnitude. Even more surprisingly, a significant percentage of city trends were cooler relative to their country surroundings. But that's because weather stations are often sited in relatively cool areas within a city, such as parks.

Finally, there have been independent analyses of global temperature datasets that have reached the same conclusions as NASA, such as the University of California, Berkeley's BEST study. The physicist who initiated that study was formerly a climate change skeptic. Not so much now!

Please use this form to provide feedback about this new "at a glance" section. Read a more technical version via the link below!

Click for Further details

In case you'd like to explore more of our recently updated rebuttals, here are the links to all of them: