Study Sheds New Insights Into Global Warming Hiatus

According to the paper, “arguably, ocean heat content—from the surface to the seafloor—might be a more appropriate measure of how much our planet is warming.”

Charting future research

In the near term, the researchers hope this paper will lay the foundation for future research in the global change field. To begin, they suggest the climate community replace the term “global warming hiatus” with “global surface warming slowdown” to eliminate confusion.

“This terminology more accurately describes the slowdown in global mean surface temperature rise in the late 20th century,” Yan said.

The scientists also called for continued support of current and future technologies for ocean monitoring to reduce observation errors in sea surface temperature and ocean heat content. This includes maintaining Argo, the main system for monitoring ocean heat content, and the development of Deep Argo to monitor the lower half of the ocean; the use of ship-based subsurface ocean temperature monitoring programs; advancements in robotic technologies such as autonomous underwater vehicles to monitor waters adjacent to land (like islands or coastal regions); and further development of real- or near-real-time deep ocean remote sensing methods.

Yan’s research group reported in a 2015 paper that some coastal oceans (e.g., U.S. East Coast, China Coast) responded faster to the recent global surface warming rate change than the global ocean.

“Although these regions represent only a fraction of the ocean volume, the changing rate of ocean heat content is faster here, and real-time data and more research are needed to quantify and understand what is happening,” Yan said.

Variability and heat sequestration over specific regions (e.g., Pacific, Atlantic, Indian, Southern Oceans, etc.) require further investigation, the authors conclude. However, there is broad agreement among the scientists and in the literature that the slowdown in the global mean surface temperature increase from 1998 to 2013 was due to increased uptake of heat energy by the global ocean.