The Gulf Stream plays a significant role in maintaining the climate of the US East Coast and Western Europe. “We conclude with a high degree of confidence that Gulf Stream transport has indeed slowed by about 4% in the past 40 years.” The full study is Here
The consequences are unpredictable. More extreme weather is about the only certainty.
The energy of the heat transfer will not just be missing in Europe. It’ll also be in excess in the Caribbeans, perhaps creating stronger winds worldwide.
Imagine a house with water radiators, where you turn off the circulation pump while keeping the furnace on full blast. It’s gotta go somewhere.
Exactly this, and those two are actually connected: The more impulse you inject into a chaotic system its attractor changes to to switch more frequently between its basins. That was rather egg-headed.
To provide a bit of intuition: Imagine a pendulum with a magnet at the bottom, hanging over a plate with magnets embedded in it, individually attracting the pendulum. Start the pendulum with a very light swing and it’s going to visit one magnet, probably circle a bit around it, switch to another, then probably back to the first, then maybe to a third, then back again. Now start the pendulum with a larger swing and it’s going to switch between pairs of states way more often as there’s plenty of energy to escape each magnet’s attraction, switching to another, it’s also going to visit more magnets.
Why? Well, consider the extreme cases: Practically zero impulse means that the pendulum will visit the magnets on its path towards hanging straight down, then get stuck on one (becoming non-chaotic and that, in our analogy, would be the heat-death of the universe, don’t worry about it). The other extreme case would be to start the pendulum at a 90 degree angle or so, it will move right through all magnets on its way to the other side, be deflected a bit, then come back and take a slightly different path.
Now, to make this more accurate: Imagine the pendulum with a little rocket motor on it, that is, it doesn’t just stop moving on its own, each magnet is a weather pattern, “rain there, wind from the north there, sunny elsewhere”. Now imagine that we’re increasing and increasing the output of that rocket. That’s climate change: Previously rare patterns become more likely and the majority of them aren’t nice.