Stronger Pacific winds could in part help explain the slowdown in the rate of global warming since the turn of the century, according to new research.
A joint Australian and US study examined why the rise in the Earth’s global average surface temperature has slowed since 2001, after rapidly increasing from the 1970s.
The research shows that sharply accelerating trade winds in central and eastern areas of the Pacific have been forcing warmer seas deeper and bringing cooler water to the surface – reducing the amount of heat that flows into the atmosphere.
The researchers say the powerful winds could have cooled the average global temperature by as much as 0.2°C since 2001.
In turn, the lowering of sea surface temperatures in the Pacific has triggered further cooling in other regions.
The latest research is another piece in the puzzle on the global warming slowdown – and the role Pacific trade winds play.
While the rate of surface temperature warming has slowed in recent years, several studies have shown that the warming of the planet as a whole has not.
This suggests that the slowed surface warming is not due as much to external factors like decreased solar activity or more pollutants in the atmosphere blocking sunlight, but more due to internal factor shifting the heat into the oceans.
The latest research follows a host of other studies that show that much of the missing heat can be found in the deep oceans. The latest study elaborates on this theory by explaining how the heat could be getting there.
While the slowdown could continue for much of the present decade if the trade winds continue, according to the latest research, rapid warming will resume when the winds return to their long-term average speeds.
Even if the winds accelerate even further, sooner or later the impact of greenhouse gases will overwhelm the effect. And if the winds relax, the heat will come out quickly. As we go through the 21st century, we are less and less likely to have a cooler decade. Greenhouse gases will certainly win out in the end.
This reiterates warnings from other scientists that the slowdown will only be temporary. Global warming has not stopped, it has just gone under water.