If one excludes data from ground-based weather recording stations that are located in the middle of large urban areas. North America has been cooling for at least the past 20 years. The same is true in many other locations such as China and Russia.
https://wattsupwiththat.com/2019/05/17/our-urban-climate-crisis/
Yeah. It’s a good analysis: heat islands have clearly biased past data. Now they say that it’s accounted for. How? A cheap scale factor on aggregated urban data?
There ARE local effects due to urban heat islands. But do they change things globally and permanently? Doesn’t make sense to think so.
Salt Lake sits next to the Wasatch range and for decades there has been a pollution problem due to a persistent inversion layer.
But the mountains keep getting heavy snow. In fact, as of yesterday morning, Snowbird had 444” so far. On February 5!!! There’s alotta years wheen thats the yearly total and everyone’s happy.
So what is the net effect? hard to say. Temperatures in the valley are actually colder due to the inversion. Some snowfall may even be facilitated by the pollution - snow forming around seed particles. So the opposite of what was thought. And the inversion layer? It’s actually a natural valley effect, been there since the Mormons got into the valley in 1847.