Lest I be too concerned as a native Illinoisian that while I am living in Phoenix in Arizona, climate change will increase the number of 115 plus days during June, July, August, and September in the urban heat-island that is expanding nonetheless, today that city is comfortably 90 degrees (F) warmer than it is in Northern Illinois. The respective highs today are 73 and -15 degrees (windchill at -35, so there is a 110 degree difference in how the temperatures feel). I have experienced -40 degree wind-chill (combining the effects of the temperature and wind speed) early on two mornings in Northern Illinois; today that wind-chill will be for at least 24 hours. Minnesota has been experiencing -60 wind-chill (and Montana, -70!). Records, all.
Why? differential climate warming (more at the arctic than at the equator) reduces the Arctic jet stream's energy. Like a tired rubber-band, the circle of air becomes wobbly, and this in turn allows the frigid air at the North Pole to escape southward. So both more 115 and 120F days during the summer in Phoenix and more belching of Arctic air in the northern Midwest of the U.S. (and in the northern E.U. too!) are henceforth more likely.
So in reading about Arizona and Illinois, you would naturally conclude that the extreme temperatures in BOTH directions are among the most notable ways we can tell that climate change is underway. The extremes already before 2020 should be understood as taking place while the oceans are continuing to absorb 93% of the increased warming of the atmosphere due to carbon and methane increases. Just think what the volatility may be like once the oceans have sufficiently heated that they will no longer absorb the excess heat!
Related Essay: "Hidden Warnings of Climate Change."
