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Chinese scientists from Sun Yat-sen University, in collaboration with their colleagues in the USA, have identified that the climate in the Northern Hemisphere is changing alarmingly. It has been found that heatwaves have intensified and are being observed more frequently in this part of the planet over the last decade, leading to significant economic losses. The research findings were published in the scientific journal Nature Communications.
The team of scientists has determined that since the late 1970s, the relationship between the El Niño/Southern Oscillation natural phenomenon and the summer circumglobal teleconnection has changed in the Northern Hemisphere. The phases of warming and cooling of the ocean surface, associated with El Niño and La Niña, have a significant impact on climate changes worldwide.
Until the 1980s, the El Niño/Southern Oscillation had a direct influence on the summer Indian monsoons, but afterward, the connection weakened, resulting in shifts in climate centers in these regions, intensified heatwaves, and the emergence of drought.
The scientists utilized reanalysis, including data on sea surface temperature, precipitation, wind, and geopotential height, and conducted digital experiments using the Community Earth System model.
They found that the Rossby waves, which shape the circumglobal teleconnection, have shifted to half-wavelength since the late 1970s. This change is related not to anthropogenic influences but to the natural variability of the climate.
The study also identified that the sea surface temperature in the equatorial part of the Pacific Ocean has shifted westward, which has affected the wildfire activity and atmospheric circulation in the tropical western part of the ocean. This, in turn, has led to the mixing of climate centers and the intensification of extreme weather events in the mid-latitudes of the Northern Hemisphere.
The scientists estimate that their research will help improve seasonal forecasts of heatwaves and droughts related to the El Niño/Southern Oscillation, as well as enhance the accuracy of models predicting future climate changes
