Distinctive Pattern of Global Warming in Ocean Heat Content

What is it about?

In spite of what Donald Trump thinks, the climate is changing, driven by human activities, mainly from changing the atmospheric composition. So these produce global heating. About 90% of the extra heating is accumulating in the oceans, while melting glaciers and land ice accounts for a lot of the rest. But the consequences are far from uniform. In a new paper, published in the American Meteorological Society’s Journal of Climate, Kevin Trenberth plus colleagues, have shown some remarkably distinctive patterns of climate change are occurring in where the greatest heating is and the consequences. As the climate changes, it has been difficult to discern meaningful patterns. The new study shows that distinctive patterns of change have occurred in the ocean when examined as zonal averages around latitude bands. “The main way the ocean continues to influence the climate is through accompanying increases in water vapor in the atmosphere that leads to the damaging increases in extremes in the hydrological cycle. Water vapor is also a powerful greenhouse gas and increased heating leads to drying and risk of drought and wildfire. But it also fuels storms of all sorts and leads to risk of flooding. That includes hurricanes and typhoons.” said Dr. Kevin Trenberth.

Featured Image

Why is it important?

Why does this matter? The changes are not uniform; regional variations can be substantial. The Atlantic is warming along with the Mediterranean Sea, and across the mid-latitude Southern Ocean. While parts of the Northern Pacific Ocean have warmed very rapidly, other areas (the sub-tropical regions) have not. The strongest warming is in the Southern Hemisphere, although sea surface temperatures have increased more in the Northern Hemisphere (where there is much less ocean). Changes in the atmospheric circulation through a poleward shift in the jet stream and storm tracks are primarily responsible along with corresponding changes in ocean currents. These changes are linked through surface exchanges of energy via heat and moisture, and wind stress. Hence the atmosphere and ocean currents are systematically redistributing heat from global warming, profoundly affecting local climates.