When scientists talk about the impact of climate change, it’s often expressed in terms of degrees. But whether the number is 2 degrees or 4, it seems rather abstract. And not that bad… after all, who wouldn’t like to have a couple of degrees on a shivery winter night? But those numbers are averages. It doesn’t mean that the temperatures slide up 2 degrees everywhere all the time. The numbers also tend to be expressed in Centigrade so … for U.S. folks, that’s 3.6 to 7.2 degrees F.
To make things easier to understand, a recent article in the journal PLOS One looked at the existing climate in cities around the world, and compared that to what they can expect by 2050 — barely thirty years away. The study restricts itself to looking at a set of large cities, and focuses primarily on what they will experience in their warmest months. The authors then looked through their database to see what city in 2019 best represents what another city will be like in 2050. For example, 2050 Baltimore can expect a climate most like 2019 Atlanta.
That study shows something of how uneven the heating is expected to be. Tokyo gets off easy, with a rise of almost exactly 2 degrees (3.6F) in its warmest month, while London jumps an astounding 5.9 degrees (10.6F). Even with London’s expected much hotter summers, both those cities fall in the “current climate regime.” That is, while 2050 London will have a climate more similar to Madrid than anywhere in the U.K., it at least has a climate that is similar to somewhere in the study. That’s not true for every city.
Within 30 years, 22% of the major cities in the study will “disappear from this current climatic domain.” In just 30 years, one city in five will find themselves “in a climatic regime that does not currently exist on the planet today.” As might be expected, that’s especially true of the tropics, where 30% of cities will experience “novel climate conditions.” Meaning simply that they will be hotter, and in some cases drier or wetter, than any city in the current study.
But the tropics aren’t alone in making this trip to a whole new world. Other areas of the planet are going to see changes that are just as extreme. Including the Eastern United States.
If you take a look at the earlier map of today’s heat wave, the area covered by that blanket of heat is going to be … covered by a blanket of heat. New York City can expect to see an average increase of 4 degrees (7.2F) and will also experience such a shift in weather patterns that it will be, environmentally, a completely different place. The temperatures in the area won’t be hotter than anywhere now on earth, but they will be hotter than anywhere now in the temperate latitudes. The extremity of those conditions can be expected to create an enormous environmental stress on plants and wildlife, as well as requiring significant changes in agricultural practices.
The West Coast shouldn’t expect to escape these massive changes. Relatively cool, wet Seattle is going to become much drier and much warmer, with an increased summer temperature of 6.1 degrees (11F). In fact, Seattle can expect to be more like San Francisco in overall climate — minus the cool breeze off the Bay. The climate in Portland, OR becomes like that of San Antonio, TX.
Around the world, the changes are severe. Europe gets not just warmer summers, but warmer winters. The result is the equivalent of taking every city on the continent and moving them 1,000 kilometers to the south. In other words, every year of the climate crisis is the equivalent of drifting 20K closer to the equator. By 2050, London is like Madrid. Madrid is like Marrakech. And Marrakech is like … nowhere on Earth today.
Those 30% of cities in the tropics might also be thought of as cities that could be well on their way to simply being unlivable. And that’s without considering sea level rise, or the effect of climate on the food supply. Those people, those billions of people, might well be expected to go elsewhere. And those places they move to will also be experiencing huge changes in their own environment.
The study might not seem very hopeful, but it is interesting, and it certainly has more impact than simply looking at the numbers.
Credit to Daily Kos & d