Using the SSP5 filter on koppen.earth for the forecasted climate based on perceived weather from 2070 to 2099, we can see that London would theoretically shift from an Oceanic climate (Cfb) to a Humid Subtropical climate (Cfa), the latter of which is normally more commonly associated with South-Eastern US states such as Georgia. This implies an increase of 3.0 celsius (5.4 fahrenheit) mean temperature compared to 1991-2020 average, as the one of the parameters required for a Subtropical climate is a mean temperature no less than 22.0 C (71.6 F) in the warmest month, currently sitting at 19.0 C. However, this would also imply that the rainfall would decrease no less than -34%, as that would otherwise shift London away from a Subtropical climate to a form of a Mediterranean or even a Semi-Arid Climate (Csa, Csb, Bsk, etc.) I personally disagree with this, especially with just how hot and dry the past several summers have been in London. London already has a surprisingly low ET (evapotranspiration/evaporation) rate because of the lack of heavy downpours that can penetrate soil, light rain lasting for hours at a time is more common there, which is simply not enough in keeping soil saturated. Just for comparison: London currently averages 600mm of annual rain with 111 wet days compared to New Yorks' 1250mm with 125 wet days. This corresponds to London having 48% the rain of New York despite only 12% less wet days. In recent years, many Mediterranean plants have been outperforming native UK plants because of drought!

Cambridge and Southend-On-Sea are forecasted to have a Semi-arid (Bsk) climate, more on par similar to my previous expectations with London. This actually makes sense, because Southend and Cambridge are somewhat drier the London, at 530mm and 560mm of annual precipitation vs 600. Perhaps that tiny margin is all it takes so change the climate from Cfa to Bsk. Now here is where things get interesting.... a sliver of Southampton and Lydd will be classified as (drumroll, please..............................) Hot-Summer Mediterranean!!! (Csa). This is indicated by yellow in the image shown below. Similar to the Humid-Subtropical classification, one of the parameters it requires is a mean temp in the warmest month above 22 C. The surrounding southern areas are more largely Warm-Summer Mediterranean (Csb). The exact parameters required to define a mediterranean climate is bit more complicated so I will just drop the Wiki link here for further reading. Lastly, the Sub-polar Oceanic climate will be completely pushed out of Scotland, only existing at the highest peaks above 1000m ASL in place of tundra. Scotland will become the new England!

Thoughts on this? I find it crazy to believe, even if it is in the far-distant future. What should I look at next?

10 hours ago, Slifer00 said:

Scotland will become the new England!

 

The name new england is already taken by a place much colder zone 3 thru 7 with tundra mountains and even some zone 4 lowlands that have had radiative lows near -50, so cold F vs C barely matters. 

London is oddly dry for nw europe but maybe it would switch with different land and sea settings. 

As we can see, these are scenarios that could happen. The example with London is difficult to understand, as many parameters would have to be right for this climate to occur.
What could happen here near Lake Constance, however, is understandable, from a cfb oceanic climate to a csa Mediterranean climate.
Looking at the plants here and the average temperatures, which are constantly rising slightly, it is very likely that this will happen. Nevertheless, we still do not know things like how much the Gulf Stream will weaken, how the jet stream will develop, how the tectonic plates will shift and at what speed -

https://www.welt.de/wissenschaft/ article184597842/Wanderung-der-Erdplatten-So-soll-der-naechste-Superkontinent-aussehen.html,

how climate phenomena such as El Niño, La Niña, foehn winds, glaciation, and permafrost will affect us or occur, and with what intensity...

 

Most doomsday predictions I've read speak to a shutdown of the North Atlantic conveyor. This would leave Britain's climate on-par with British Columbia's. (If we are to believe the most unreliable profession in society)