Global warming has changed the Pacific Ocean - what scientists discovered

Researchers at the University of California, San Diego have modeled the impact of global warming on Pacific Ocean water circulation 100 years into the future. They found that in the subtropics of the northern part of the ocean, water will "age" due to reduced inflow of young water from the surface, while in the tropics it will "grow younger" due to reduced inflow of old deep water. This will affect oxygen levels and living conditions for marine organisms.

Researchers from the University of California, San Diego have modeled how global warming will change the circulation of Pacific Ocean waters over the next 100 years. The focus is on the Pacific thermocline, a layer at a depth of 200–1000 meters between warm surface and cold deep waters. Warming makes the upper layers warmer and lighter, strengthening their separation from deep waters and slowing vertical mixing. The consequences turned out to be uneven: in the subtropics of the northern Pacific Ocean, less young water will flow from the surface, so it will become "older." In the tropics, conversely, the inflow of old deep water will decrease, causing water masses to be younger on average. Some changes are linked to warming of the Southern Ocean around Antarctica. Water age affects oxygen content, so the most noticeable consequences may appear in the northern Pacific Ocean and affect living conditions for marine organisms. The conclusions are still based on a simplified model; for more accurate forecasts, researchers plan to account for wind and other factors.