As ocean surface temperatures rise to record highs, the World Meteorological Organization said Wednesday it expects a shift toward El Niño this fall, which could alter weather patterns and trigger more extreme weather events in the US. USA and other parts of the world.
Forecasters expect the El Niño weather pattern to alter rainfall patterns, raise average air temperatures, and contribute to more intense storm systems. The El Niño pattern, which is a temporary and natural climate anomaly, will be superimposed on warming attributable to human-caused climate change. Both trends raise average air and sea temperatures.
Daily sea surface temperatures last month reached highs not seen in at least four decades of records, according to a data visualization from the University of Maine Climate Reanalyzer.
“As surface temperatures rise, more fuel is added to the atmosphere, and that fuel is heat and moisture,” said John Abraham, a professor and program director at the University of St. Thomas’ school of engineering who studies ocean temperatures. “It intensifies weather patterns. It means the weather gets more extreme.”
The combination of El Niño and the long-term trend of global warming could produce new record global temperatures and exacerbate the impacts of climate change.
For the past three years, the world has been stuck in a La Niña trend, which has offered something of a respite. He WMO forecasters say trend is now neutralbut forecasts there is an 80% chance that El Niño will take hold in September.
“We have just had the eight warmest years on record, even though we had a cooling La Niña for the last three years and this acted as a temporary brake on global temperature rise,” said WMO Secretary General, Petteri Taalas, in a statement.
The National Oceanic and Atmospheric Administration’s Climate Prediction Center last month issued an El Niño alert and a prediction similar to the WMO.
El Niño is associated with cool, wet weather in the southern US and warm conditions in the northern states. Parts of the US, such as the Ohio River Valley, could experience a prolonged dry stretch as El Niño takes hold.
Ocean temperatures are determined by analyzing data from a network of monitoring buoys and robotic devices that track temperatures as they travel up and down within the ocean. These devices send data to researchers and help forecasters predict the weather.
Rising sea surface temperatures are an indication of the transition to El Niño.
“They are blowing the doors off the previous record,” Abraham said of those measures. “The warming of the ocean is the most important thing that determines the climate. So this is not a problem for seals and polar bears; it is a problem for us, our societies and agriculture.”
The oceans absorb most of the energy from human-caused warming. Over 90% of the heat imbalance in Earth’s energy inventory ends up in the oceans, according to the United Nations Intergovernmental Panel on Climate Change.
Ocean surface temperatures tend to fluctuate and are subject to shorter-term trends and natural climate variability such as El Niño. But much of the added heat is contained below the sea surface, said Sarah Purkey, an assistant professor of physical oceanography at the Scripps Institution of Oceanography at the University of California, San Diego.
«Ocean heat content is the most important metric to look at when we think about climate change because it’s really at the core of this global imbalance,» Purkey said. Beneath the surface, «we’ve had this signal of really consistent warming.»