Europe’s mild climate is not caused by the Gulf Stream alone. The warm water that reaches Europe is carried mainly by the North Atlantic Current, the northeast extension of the Gulf Stream and part of the Atlantic Meridional Overturning Circulation. Atmospheric westerly winds explain most of Europe’s winter warmth relative to the same latitudes in eastern North America, with ocean heat transport providing an important but secondary contribution.
What is the Gulf Stream?
The Gulf Stream is a fast, warm western boundary current that flows north along the U.S. East Coast, then turns east near roughly 35 to 40 degrees North into the open Atlantic. It is primarily driven by winds that power the North Atlantic subtropical gyre, and it is well known to navigators and oceanographers for its speed and temperature contrast with surrounding waters. Benjamin Franklin helped chart its path in the 18th century, and it remains one of the best observed currents today.
The Gulf Stream does not flow across the Atlantic to Europe; it turns east near 40°N, where its waters and momentum feed currents farther downstream (NOAA).
What is the North Atlantic Current?
The North Atlantic Current (often called the North Atlantic Drift) is the broad northeastward flow that continues from the Gulf Stream across the North Atlantic toward Europe. It splits into several branches that carry heat toward the British Isles, the Norwegian Sea, and the Barents Sea. This current directly bathes Western Europe in relatively warm surface waters, tempering coastal climates compared with continental interiors.
What is the AMOC and how is it related?
The Atlantic Meridional Overturning Circulation (AMOC) is a large-scale system in which warm, salty surface waters flow northward, cool and sink in the subpolar North Atlantic, and return southward at depth. The Gulf Stream and North Atlantic Current are part of the surface limb of this system, but the Gulf Stream itself is largely wind-driven and not the same as the AMOC. Observations at 26.5°N show that overturning strength varies substantially from year to year and contributes a portion of the total northward heat transport (RAPID AMOC).
AMOC describes the basin-scale conveyor of heat and salt, while the Gulf Stream is the fast western boundary current; they are related but not interchangeable (WHOI).
Does the Gulf Stream keep Europe warm, or is it the atmosphere?
Both the ocean and atmosphere matter, but they play different roles. Studies comparing Western Europe to eastern North America at the same latitude show that prevailing westerly winds and atmospheric circulation patterns explain most of Europe’s milder winters, by transporting maritime air and shaping storm tracks. Ocean heat transport, delivered to Europe by the North Atlantic Current and the surface limb of the AMOC, further moderates nearby coastal regions and the Nordic seas.
In other words, it is inaccurate to say the Gulf Stream alone keeps Europe warm, and it is also inaccurate to ignore the ocean entirely. The Gulf Stream feeds the downstream currents that carry heat toward Europe, while the atmosphere spreads that warmth over land. For a detailed synthesis, see analyses by NOAA Climate.gov and peer-reviewed work such as Seager et al. (2002) in the Quarterly Journal of the Royal Meteorological Society (DOI).
NOAA concludes that westerly winds and atmospheric circulation account for most of Europe’s winter warmth relative to eastern North America, with ocean currents providing an important additional boost (NOAA Climate.gov).
Could changes in the AMOC or Gulf Stream cool Europe?
Climate models and observations indicate the AMOC will likely weaken as greenhouse gas concentrations rise, due to warming and freshening of North Atlantic surface waters that reduce deep-water formation. The latest assessment finds a weakening this century is very likely, while a full collapse before 2100 is considered unlikely, though not ruled out, given remaining uncertainties (IPCC AR6). Multiple studies also suggest the AMOC today may be weaker than in the early 20th century, but estimates differ on magnitude and causes.
If the AMOC weakens, the North Atlantic region would likely see cooling relative to the global average, changes in storm tracks, and sea level rise along parts of the North American east coast. This would not trigger a sudden ice age, but it could offset some regional warming and alter weather patterns. The Gulf Stream, being largely wind-driven, would continue to flow, though its downstream heat delivery and the structure of the North Atlantic Current could change with the AMOC.
Key takeaways for Europe’s climate
- The Gulf Stream proper runs north along North America then turns east near 40°N; it does not flow along Europe’s coasts.
- The North Atlantic Current carries warm water toward Europe and is the oceanic pathway most directly moderating Western Europe’s coastal climate.
- Atmospheric westerlies explain most of Europe’s winter warmth versus eastern North America at the same latitude, with ocean heat transport adding an important boost.
- The AMOC links these flows in a basin-wide overturning; it is projected to weaken, which would shift regional climate but not cause an abrupt ice age.