Global warming changing old ideas of climate understanding: experts

Despite fears that India will experience a ‘below normal’ monsoon in an El Nino year, rainfall in July was 15% ‘above normal’. According to global scientists, this anomaly is due to global warming changing old ideas about climate and the need to adopt new mechanisms that drive climate.

In a recent observation, climatologist Emily Becker of the University of Miami/CIMAS said that, in general, the stronger the sea surface temperature (SST) anomaly, the stronger the atmospheric response, and the more consistent the pattern of El Niño’s remote influence on precipitation and temperature patterns. However, a warming global ocean may complicate this relationship.

Vineet Kumar, a former scientist at the Indian Institute of Tropical Meteorology (IITM), said, “Due to record warm global SSTs, ocean temperature gradients are not the same as they were during classical El Niño conditions. As a result, despite ocean conditions under El Niño conditions, the atmospheric response to El Niño is weak, resulting in very little influence of El Niño on the monsoon.

Swapna Panickal, scientist at IITM, said the IPCC (Intergovernmental Panel on Climate Change) report shows that as the global surface temperature rises, the availability of moisture will increase and hence rainfall will increase in the summer monsoon, albeit with greater variability. Extreme El Niños are predicted to increase with warming. Therefore, summer monsoon rainfall will be more variable in the coming decades.

The seasonal monsoon forecast issued by the India Meteorological Department (IMD) indicates normal (96-104% of long-term average/LPA) monsoon conditions over the Indian region. El Niño is one of the dominant external drivers of the monsoon, causing below-normal rainfall in India. However, other factors such as the positive Indian Ocean Dipole (IOD) and snow cover in the Eurasian region also influence the summer monsoon rainfall. A positive IOD can lead to more than normal rainfall in the Indian region, Panickal said, adding that the Eurasian ice sheet has an inverse relationship with Indian summer monsoon rainfall. A weak El Niño condition developed in June with above-average SSTs across the equatorial Pacific Ocean. The El Niño forecast suggests continued growth of El Niño through the fall, with moderate-to-strong intensity this winter, Panickal said.